Insulation Contractors Near Me

Looking for Insulation contractors in your area? Learn what to take into consideration before you hire a contractor, so you never overpay or get scammed.

The main purpose of insulation is to control the interior climate of the house at minimal cost. Keeping the house warm or cool requires use of electricity, gas, or other forms of energy which add a significant cost to your energy bills. Insulation helps to reduce the need for energy to control the climate and you will be able to save upward of $400 per year. A well-insulated house will be warmer than the outside during winter and cooler than the outside during summer. Insulation prevents unnecessary loss of energy and keeps out excessive heat and draughts from outside.

Areas for Insulation

Some of the areas that require attention for insulation include the;

  • roof and loft
  • floor
  • walls and wall cavities
  • plumbing including tanks, pipes, and radiators
  • entryways and windows
  • moisture/condensation in the house
  • draught-prone areas

Insulation can also be done to create sound and light ambience in the home. It can also be done for fire and impact insulation.

To DIY or to Use the Pro

While the task of insulation a house is simple enough, it is messy and undesirable for many home owners according to The project may involve adding on, retrofitting, finishing a remodel, or repair of existing insulation. Many house remodeling projects include insulation, since retrofitting would cost a lot more to implement and may not be worth the while to invest in. An insulation project involves opening up the wall, ceiling, window panel, floor, or plumbing.

Reasons to Insulate

Meeting Homeowner Needs

New home owners are looking for houses that have all the amenities, which include energy-efficient appliances, and effective house insulation.

Lower Energy Bills and Greater Energy Efficiency

An energy efficient house is in higher demand than an uninsulated house that guzzles energy. Environmentally-friendly homes are preferred for their lower CO2 emission or carbon footprint. When less electricity is used you save fuel burning at the power plant or water in the dam. Energy costs alone represent at least 5 percent or $2,200 of the average home’s total income.

Sound Insulating Adds to Living Comfort

A quiet home is a haven for the family, and a good insulation, especially with ICF, adds to the acoustic barrier from street noise and from adjacent rooms in the house.

Insulation for a Healthier Home

A warm living room with good ventilation, and less humidity creates a healthy indoor environment. Good insulation, moisture retarder, mold retarder, and air seal reduce air-borne and moisture-borne pathogens, pollens, and dust that cause pulmonary complications. The structural and insulation materials have to be equally safe for health. .

Home Improvement (Insulation) Tax Credits

When you carry out a home improvement project such as insulation, air sealing, weather stripping, caulking, energy-efficient AC or HVAC system, or house wrapping in your home you become eligible for a government tax credit of up to $500 or 10 percent of the cost of materials, a rebate of up to 30 percent, or both. This is only available to the home owner who lives in the residence.

The credit is used also for replacement of a previous insulation with an improved insulation. You must provide paper evidence of the insulation work. You submit the Residential Energy Credits when file your tax returns. You should check what insulation tax credits are available to you from

State and Utility Company Insulation Rebates

Rebates are incentives offered by the utility companies for energy efficiency. According to the, home owners can claim utility company rebates Some of the equipment and fixtures affecting insulation that qualify for rebate include; dehumidifier, AC, HVAC, fans for ceiling, ventilation, and cooling, furnace, roof, window, and door insulation and weather stripping, and heat pumps.

Choosing an Insulation Contractor

The job of insulation is not as technically demanding as some of the other types of projects. However, it is cumbersome to DIY, is considered too menial by others, and it involves hazardous chemicals. It is therefore better to leave the job to an insulation expert.

Before selecting the right local insulation contractor, get two or three quotes showing a breakdown of materials and labor. Do a research on the costs and availability of materials that are suited to your house and location. Since most insulation materials are fairly standard, the quotes should be more or less similar on pricing (you need to factor in the cost of transport).

Ensure that you hire an insulation contractor who is affiliated to the National Insulation Association and a local chapter of the Insulation Contractors Association of America, whose members adhere to certain standards and codes of ethics. The associations also arbitrate between insulation contractors and their customers.

The internal solid wall insulation should only be done by a certified insulation contractor for it to qualify for energy and insulation rebates and tax credits. When seeking for the rebates or tax credit you need to provide evidence of costs of materials and labor (although labor does not qualify for the rebate or tax credit). You also need to keep photographic evidence of “before” and “after” in case of a dispute over the contract work done. It is easier and cheaper to implement the insulation alongside a new construction or remodeling. If the insulation task is a stand-alone project and in a specific area, for example internal wall insulation, then it is best to engage a specialist insulation contractor, even though they come at a premium price to give you the comfort you deserve, which is worth more than all the rebates, tax credits, and energy savings.

Many insulations are installed to last and therefore the insulation contractor’s warranty should be an extended one too. Do note however that a long guarantee is difficult to implement as you will likely remodel the house in future and interfere with the insulation, upgrade the insulation to meet future standards, sell the house, and so forth.

Find the right insulation pro near you by searching the internet, searching through insulation member association like Insulation Contractor Association of America, and the National Association of Homebuilders.

Insulation Effectiveness Indicators

When it comes to selecting the residential insulation, you need to compare the various types of insulation available to you. According to the Building Sciences Corporation, all insulations perform equally well when installed correctly and air sealed, and all products have their strengths and weaknesses. You still want to consider a number of factors. Heat is lost from the house in the following areas;

Areas/Cause of Heat LossPercentage of Total Heat Loss
Exterior Walls23.00%

1. R-value

The R-value measures the resistance to heat penetration through an object. It is a crucial factor in insulation as the materials used have to form a strong barrier to loss of heat or entry of cold air. The US Energy Star agency has a map of recommended insulation by R-value and cost effectiveness. Aim to maximize your R-value per dollar. The R-values to add to the attic/floor are shown in the following table;

ZoneUninsulatedExisting 3-4” InsulationFloor
1R30 to R49R25 to R30R13
2R30 to R60R25 to R38R13 to R19
3R30 to R60R25 to R38R19 to R25
4R38 to R60R38R25 to R30
5R49 to R60R38 to R49R25 to R30

2. Moisture

Other factors of heat transfer that determine the effectiveness of insulation are convection, conduction, radiation of heat by air and moisture, accumulation of moisture, air infiltration, and air intrusion. Moisture absorbs heat energy and releases it slowly, therefore is poor at radiation but good at conduction and convection. Air is a resistant to radiation and conduction of heat, but is excellent at convection. Spray polyurethane foam prevents all types of heat loos by water and air.

3. U-value

The U-value is the rate of losing heat energy through a barrier such as wall. Ideally the U-value should be less than 0.3 watts per square meter-Kelvin. ICF has a low U-value, making it an excellent choice for insulation. The thinner an insulation block is the higher its (undesirable) U-factor is.

4. Air Infiltration

According to the National Association of Home Builders Research Center, when fiberglass and mineral wool are paired with air sealing materials like caulk and taped house wrap, they achieve a near 100 percent air lock. Spray forms are by nature air sealants.

5. UV Resistance

Products that are unaffected by exposure to UV radiation, such as mineral wool, give uniform insulation without degrading, but insulations that react to UV exposure, for example spray foams shrink on over-exposure, lose their R-value over time.

6. Material Settling

Materials like fiberglass and mineral wools do not settle or compact, giving a uniform service throughout their life cycle. Cotton batts will gradually settle over the years as they absorb some moisture, thus lose their efficiency.

7. Acoustic Efficiency

A quiet environment is more livable than a noisy one. Most noise comes from the street, adjacent TV and play rooms, and the neighbor’s dog, and penetrates through the roof, attic, walls, doors and windows. Dense and heavy mass materials such as ICF and mineral wool have a good noise reduction coefficient or NRC of 1.00 compared to lightweight and air-filled materials like spray foam or polyethylene with an NRC of 0.75.

8. Fire Rating

A good insulation incorporates fire retardation. Unless the material is naturally non-combustible, for example mineral wool and fiberglass, you need to add a fire retarder such as gypsum board. Spray foam ignites at 700 degrees Fahrenheit. Cellulose is quite flammable on its own, and requires a fire retarder component of at least 20 percent. Rigid insulation is normally made fire resistant using gypsum board.

9. Moisture and Mold

Some insulations are moisture resistant, for example fiberglass, cellulose absorbs up to 20 percent of moisture by its weight, and rock wool batts hold 2 percent of moisture by weight. Moisture encourages mold formation, which is a health hazard.

10. Health Impact

Choose an insulation that has fewer chemical components or less loose dust particles. Some people are skeptical about the safety of such insulation as spray foam containing isocyanates, which does cause skin irritation during installation. Fiberglass, mineral wool, concrete board, and other insulations have no ill-effect on the house occupants.

House Insulation Cost

You should start the insulation project by conducting an energy audit which will reveal how energy is used in the house and give recommendations on how to cut back on the use. Since most energy goes into heating and cooling, the recommendations will dwell a lot on insulation, ventilation, and weatherizing. For insulation, the audit report will likely highlight the attic as the biggest escape route for house heat, the walls, the entryways and windows which let in cold draughts, and the floor which is damp.

According to, the average cost of insulation of the attic is between $1.00 and $1.50 for standard materials.

Insulating the ventilation at a cost of between $30 and $40 per venting unit and air sealing around knee walls and chimneys will cost a total of $1,200 in materials and $2,500 in labor.

Insulating the walls to the Building Code standard and energy recommendations, you need an R-5 value wall sheathing and R-15 cavity insulation.

The sheathing costs about $1.00 per square foot, while the cavity insulation cost around $0.75, therefore the total cost of materials for the wall insulation is $1.75 per square foot. The insulation expert or carpenter will spend 30 man-hours on the job and charge $50 per hour for a total of $1,500.

Spray foam insulation costs range from $0.45 to $0.65 per square foot of board, while closed cell spray foam will cost $1.00 to $1.50 per square foot the average cost of the project is $2,200 (

Blow-in insulation uses a special blowing machine that can be rented for $100. The materials cost about $500 to $1,000, and labor charges. Other estimates put the cost at $1,360 or as high as $1,900. The project should take some 5 hourly or so.

Energy and Cost Saving With Insulation

Energy Saving

Insulation contains heat energy within the house, and especially in the living room. You should take other measures to help make the insulation work for you. For example you can install an intelligent or programmable thermostat that is controlled from a smart phone to switch on heating appliances at the right time, set the temperature of water and air according to the preset ambience, switch off appliances when not in use or everyone is out of the house, and direct heat to where the occupants are, for example to the bedroom at night, living room in the evening, dining room at meal time, and so forth. This way the insulation will be optimized and energy bills lowered. Switching from boiler heating to instant shower can save up to $30 in energy costs and $40 in water bills per person annually.

If you have a large home or an extension, you will need to improve the general insulation. Add extra insulation to the air vents, ducts, and hot water plumbing so they can conduct more volume further from the source without a significant heat loss. Position the heating units (boiler and HVAC) centrally in the house so as to reduce the distance to any part of the house. Create a two- door entryway and exit so that when the outer door is open only a small amount of the interior is affected by the exposure to the elements.

Prioritize the external moisture control and insulation of the house including the external walls, door and window weather stripping, and attic, before moving in to the interior walls, heating systems, and HVAC system.

Cost Saving

Caulk and air leak seals around the plumbing lines, recessed lighting, crawlspace, attic, windows, doors, and electric wiring will save you up to $230 a year in energy bills. If you spend $300 on weatherproofing the doors and windows, you will cut energy expenses by $40 per year. For best energy saving outcomes, combine insulation with energy-efficient appliances and equipment.

Replace aged boilers, worn out radiators, piping, vents, and air ducts. Duct wrapping with R-15 or R-19 to stop leaks in the HVAC system will save up to $420 per year and reduce condensation. Reducing the water temperature by 10 degrees will save $12 to $30 per person per year, and allow the insulation to work more efficiently at lower temperature. Insulating the attic will cut down the energy bill by up to $350 per year.

Note that all the measures are interdependent and therefore do not result in a cumulative total saving on individual measures. Some utility companies have an energy improvement fund to help meet the cost of insulation. States also have energy saving rebates as detailed in the federal database DSIRE ( and Energy Star discount and rebate finder at

Energy savings accrued from insulation in the U.K. in 2017 according to, and which compare well with energy savings in the U.S., are as follows;

DetachedSemi detachedMid terraceBungalowFlat
Energy Bill per Year$330$220$140$150$110
Typical installation cost$1,300$850$750$800$700
Payback timeLess than 5 years
CO2 Emission savings2,250 lbs.1,400 lbs.800 lbs.910 lbs.600 lbs.
Financing Options

If you are short on funds, you can seek assistance to finance your insulation project. Many states offer rebates on energy efficiency upgrades, including insulation measures taken. If you are putting up a new house you can incorporate insulation in the whole-house-design and seek rebates for the energy and insulation components.

Insulation for different Climates

Cold Climate

The cold regions need the crawl space to be sealed off from the external elements and air leaks by using a high R-value insulation along the walls. This ensures the HVAC and plumbing pipes are protected from freezing. A thick and rigid material is used. The professional will install the material at $2.50 for materials and $2.50 for labor per square foot.

The existing vents are removed and the holes sealed. The rims of the joists are insulated with closed-cell spray foam. The foundation is then insulated by a rigid, glued foam board on the inside of the foundation walls. A 2” thick sheet of XPS with R-value of 7.7 per inch is used and costs $26 per square foot. A double layer will serve even better. Add a vapor barrier, such as a 6-mil polyethylene plastic to keep ground moisture at bay. It is recommended to control moisture in the crawlspace for example by adding a dehumidifier or linking the space to the HVAC system through vents.

Warm Climate

For warmer winter areas, the insulation thickness is 6” or R-19 fiberglass batts between joists. Mold prevention and moisture control are needed too. The cost of such an installation is about $1 per square foot. The batts are unfolded onto the subfloor and supported with wood lath placed at 18” intervals. A crisscrossing of the web wire can be used, but avoid stay rods or tension rods which can compress the batt and reduce its R-value.

The contractor then calculates the required amount of ventilation and cuts new vents. A spray foam is then used to seal the holes and gaps created by electrical and plumbing installations. The plumbing and HVAC ducts are then insulated. The webbing between truss types needs to be sealed with a closed-cell spray foam which cost $5 per square foot. The open-cell spray foam is unsuitable because it absorbs moisture.

Protective Gear for Insulation Work

Whether you decide on DIY or settle for an insulation pro near you, the person working on the job must wear protective clothing, as many materials contain hazardous chemicals and dust particles. The attic should be done on a cool day as it tends to get very warm on a hot day. The gear to wear should be disposable gloves, overall, work boots, double elastic mask or a half-face mask, goggles, and a helmet. A head-mounted light or droplight and a pair of long and strong planks to support the worker between joists are essential. Move all the materials up the attic before starting the insulation work.

Classification of Insulation Materials

The choice of insulation depends on the area to be insulated and your budget. Insulation materials can be categorized in several groups; batt and blanket, loose-fill, spray foam, SIPs, and insulation concrete forms or ICF insulation. There are different types of insulation in each category.

Batt and blanket insulation

This is a common insulation material in form of batts or rolls. The material is affordable, easy to transport, light, and easy enough for a DIY to do. Batts consist of flexible fibers, mineral rock wool, slag wool, plastic fibers, cotton or “blue jeans”, wool from sheep, and other natural fibers. Batts can be either unfaced (no outer moisture barrier covering) or faced. Batt facing is done with Kraft paper, vinyl, or foil Kraft and it acts as a fire retarder. It also helps with the fastening of the batts to the wall during installation. Batts are cut to size to fit standard spacing of wall studs, attic trusses, floor joists, and roof rafter. It however creates waste when it is cut to fit the shape and size of the surface, around plumbing, wiring, and other fittings. The R-values for most batts are as follows;

DepthR-ValueCost per Sq. ft.
3.5”11$0.12 - $0.16
3.6”13$0.15- $0.20
3.5” HD15$0.35 - $0.40
6.25”19$0.27 - $0.35
5.25”21$0.33 - $0.40
8.5” HD25$0.37 - $0.45
8.0” HD30$0.45 - $0.50
9.5”30$0.40 - $0.45
12”38$0.55 - $0.60

Because a DIY is likely to do a clumsy insulation with batt and blanket, leading to big loss in effectiveness, it is best to leave installation to an insulation expert near you.

Fiberglass Batt and Blanket

The fiberglass batt and blanket is used in insulating walls, floors, and ceiling. It is easy to apply by a DIY at a . It has an R-value of 3 to 4 per inch. It is widely available with different standard sizes available. It has a uniform and standard thickness and width, which allow for fitting between studs, joists, and rafters. The material has flanges for stapling or gluing it to the next roll. The fiberglass materials is however itchy to work with and you therefore need protective clothing. It has to be cut by hand and it easily compresses and loses its insulation properties. Phenol Formaldehyde used as a binder is linked to cancer. When inhaled, the fibers quickly break down in the lungs and permeates the body. Fiberglass batt and blanket is 60 percent recyclable. The cost of fiberglass batt varies according to the density and thickness of the material.

Size (Depth)R-ValueCost
3 ½” 15$0.35-$0.40
5 ¼”21$0.35-$0.40
6” – 6 ¼” LD19$0.25-$0.35
8 – 8 ½”25$0.35-$0.45

Mineral Wool Batt and Blanket

Mineral wool is a man-made, fire rated insulation material made from either rocks (minerals) or slag, and contains 75 to 90 percent recycled material. It is made from basalt, diabase, and other natural rocks. Slag wool is the “ash” from blast furnaces. The rock wool is mainly used for insulating walls, floors, and ceiling, and costs about $0.60 per square foot of material. It has a major fire rating advantage over fiberglass. The R-value of the rock wool batt and blanket is between 4 and 5 per inch. The material is environment friendly because it is 90 percent recyclable, but with traces of a carcinogen called crystalline silica. Since rock wool can easily spring back to shape against studs, it does not require staples to join with the next material. The material is however not widely available, more expensive, moisture absorbent, and encourages molding and mildewing.

Cotton Batt and Blanket or “Blue Jean”

This is a material derived from cotton with an R-value of between 3.5 and 4.0 per inch. It is best used for insulating walls and hot and cold areas like tank and pipe systems. It is easy to cut and fit in small spaces. It has 85 percent recyclable content and needs little energy to manufacture. It contains borate fire retardant, which incidentally also repels insects. The cost of the material is $0.90 per square foot.

Loose-fill or Blown-in Insulation

This is a lightweight insulation material that is made from foam beads, loose fiberglass, loose pellets, cellulose, and mineral wool, which is blown into cavities using a special machine. Other less common materials include polystyrene beads, perlite, and vermiculite. It is advised that you hire a professional insulation installer because they have the correct blow-in machine for installing the insulation, know how to achieve the correct density and R-value, and can identify areas of energy loss that you may not recognize. The blown-in insulation can fit in any space no matter the shape and size, including wall cavities, and attic drywalls, although cellulose and rock wool are not suited to a half drywall with 24” width on center. A vertical frame holds the pieces together at every linear foot interval.

Manufacturers are required to give all the information regarding the R-value and density of settled insulation, weight per square foot, coverage according to thickness, and so forth. The settled density of loose-fill material on walls increases under its own weight, leading to a disproportionate distribution of its R-value. Being fluffy, a significant amount of the fiber is lost during winter, therefore it has to be augmented by a cellulose or blanket insulation. It is best used for ceiling and wall insulation. The recommended mixture ratios are compared as follows;

CelluloseFiberglassRock Wool
Density1.52 – 2.2 lbs/ft30.5 – 1.0 lbs/ft31.5 – 2.0 lbs/ft3
Weight 1.25 – 2.0 lbs/ft30.5 – 1.2 lbs/ft31.6 – 1.8 lbs/ft3

Loose fill has an R-value of 3.2 to 3.8 per inch and costs the same as fiberglass at $0.30 per cubic foot. The cellulose insulation is 85 percent recycled paper and 15 percent fire retardant, and has traces of borate compound to deter insects. You can recycle up to 60 percent of the material.

Loose-fill insulation is effective at all temperature ranges, especially in cooler temperatures, but it is too heavy for attic installation. The ceiling has to have at least a 5/8 inch thick drywall or a framing at 16 inch intervals. Its effectiveness diminishes by as much as 20 percent over time. The fibers are large and will not be absorbed by the lungs.

Spray Foam Insulation

Spray foam insulation forms a barrier to air flow and, in the case of closed cell foams, a moisture barrier. Foam insulation is mixture of two compounds – a foam and a foaming agent – that react, expand, foam, harden, and eventually cure when the compounds mix. It is lightweight, non-structural, airtight, and quick to apply. Some spray foams have a higher R-value per inch than batts and can squeeze into small spaces to form a tight air barrier.

Materials used in the spray foam insulation include cementitious, polyurethane, polyisocyanurate (polyiso), and phenolic. Icynene foam is a good air and vapor retarder, and tri-polymer foam is fire-rated and air sealant which are less commonly used. The spray foam is particularly recommended for the basement and crawlspace, plumbing, air ducts or piping, HVAC system, and hard to reach areas of the attic or roof. It is also recommended for the joints between foundation and siding, gas and electrical penetration, wall joints, water tank, stone wall repair, garage ceiling, wall cavities, pool covers, and faucets and vents. Choose a closed cell spray foam for areas that experience moisture leaks or humidity, noting that this foam costs twice as much as the open cell spray foam. There are two types of spray foam insulation; open-cell or half-pound and closed-cell or two-pound foam insulation.

  • Open-cell Spray Foam Insulation

The open-cell spray foam insulation is made in part from biological matter, carbon dioxide, and water, and from polyurethane derived from petroleum or plants. Since the polyurethane is porous, it absorbs moisture and therefore has to be used with a moisture barrier such as gypsum board, which also acts as a fire retardant. The insulation has an R-value of between 3.5 and 3.6 per inch, and a density of 0.5 pounds per cubic foot. It is not recommended for roof sheathing or below grade where it can absorb moisture.

  • Closed-cell Spray Foam Insulation

The closed-cell spray foam is made of the same materials as the open-cell version, but it has an added special gas to slow down the curing, form an air-tight barrier, and resist moisture infiltration. It contains hydrofluorocarbon or HFC which harms the ozone layer and some home owners prefer to use a fiberglass batts in place of the HFC-laden spray foam insulation. Since the slow process forms smaller foams, it is denser at 2 pounds per cubic foot, and a high R-value of 6.0 to 6.5 per inch. It is suited to roofs, ceiling, wall, and floor. It is a professional job.

Installation of Spray Foam Insulation

Any significant insulation task should be left to the insulation professional near you, especially because you need a specialized foam spraying equipment, all-body protective clothing, and approval from the building code.

The foam and the foaming agent are sprayed, injected, or poured in simultaneously from different canisters into the wall cavity, attic, ceiling, crack, or gap. The mixture then bonds, foams, expands, hardens, and cures. Slow-curing foams are designed for awkward spaces when it taken longer to flow. Small pressurized cans of spray foam insulation can be used to repair small gaps, fill spaces left by SIP cuttings, seal air leaks around door frames and window sills, and other small DIY jobs. Once you have applied the spray foam, you do not have to caulk or weatherize the window sills and door frames. A vapor retarder and a thermal barrier with a resistance equivalent to a ½” gypsum board are required by the building code to cover the insulation. The insulation agents remain toxic until they are cured.

DIY Foam Insulation Kits

If you prefer to do your own insulation with spray foam then you can select from such brands as Foam It Green, FOAM IT, Tiger Foam, Touch ‘n Foam, Handi-Foam, Touch N Seal, FomoFoam, among others. A kit costs between $150 and $300 and you need 2½ kits to do a 200 square foot area. When the icynene is released from the can, heated, and exposed to air it expands 100-fold. The user has to wear protective clothing including a face or gas mask and to have the skill to spread it evenly. In general, it is ill-advised for you to undertake this task, especially if it a large-scale one like attic, garage, house, or basement, leave it to the insulation expert near you. You can DIY small scale insulation such as sealing the plumbing, repairing a crack, crawl space, or some small scale project.

Advantages and Disadvantages of Spray Foam

Using spray foam as advantages to both you and the insulation expert. It has the highest R-value, of up to 6.6, compared to other insulation materials. It is twice as efficient as traditional insulation methods. Since 40 percent of house energy is lost to poor insulation, a properly done spray foam insulation can reduce the loss to just 10 or so percent (U.S. Department of Energy). Spray foam is applicable in virtually all areas of the house. In its fluid form, it fits snugly and smoothly around awkward spaces, crevices, bends, and curves.

The closed cell spray foam is further enhanced by its moisture leak prevention. It has the added advantage of acting as an acoustic barrier, mold inhibitor, and bug repellant. However, application of the material causes skin and eye irritation, chemical inhalation, chest tightness, different aches, and when burnt, it releases toxic fumes that destroy the ozone layer. The insulation contractor should look for a brand that has fewer of these side effects, especially spray foams that have little or no isocyanates.

Cost of Spray Foam Insulation

Generally, spray foam insulation is more expensive than the more common batt insulation. The open-cell spray foam insulation of R-value 3 per inch costs between $0.40 and $0.70 per square foot, while the closed-cell spray foam insulation costs between $1.00 and $1.50 per square foot, according to Since closed-cell spray foam insulation has a high R-value per inch and tight air leak sealing, it does not require additional costs of weathering like caulking, joint taping, house-wrap, or vapor barrier. Styrofoam is an XPS material with an R-value 5 per inch and costs $0.42 per square foot. It is sold in panels of 4’ by 8’.

The national average for a 1,300 square footprint is $2,200, with the low end costing just $500 and the high end costing $6,000.
Elderly and sickly people need good insulation using natural materials, which do not worsen their health situation, but natural materials are more expensive and bulkier than chemical-based materials. Soybean-based closed-cell spray achieves R-value 4.5 to 5.2 per inch, but it costs $1.8 to $2.3 per square foot. The average cost of using a spray foam in a standard house is $1,482 – $3,290 and takes about 12 hours, according to

Comparing Insulation of New Construction and a Retrofit Insulation Project

A new house will be built in accordance with the building code which incorporates a minimum of insulation measures. The new house design will integrate insulation as part of the construction and will therefore not require a new project to complete it. A new house insulation is much cheaper than starting a separate insulation project that will involve some demolition, wiggling through tight spaces, and hiring an insulation contractor. Insulation spray foam is not recommended for older homes as there are many spaces that are hard to reach.

Structured Insulation Panel (SIP)

A SIP is a prefabricated, rigid board that is used for insulation. It is made of an inner core of polystyrene or polyisocyanate foam, an outer shell of oriented strand board or OSB, and then sheathed on the outside. The facing is glued to the foam core, pressed until it bonds, and allowed to cure. It is resistant to delamination and it edges are smooth to allow for a tight fit. It has structural strength to support weight, and a uniform insulation. Its R-value is high, resulting in a 12- to 14 percent saving on heating energy costs. It is usable in all areas; such as the basement, crawl space, walls, and ceiling. Its thickness and tight fitting create a soundproofed and comfortable space.

  • EPS and XPS

There are two types of SIP; extended polystyrene SIP or XPS and extruded polystyrene SIP or XPS. The EPS is inexpensive at $0.20 per square foot, lightweight, and has an R-value of 3.8 per inch. The XPS costs $0.45 per square foot, is lightweight, stronger, moisture-resistant, and has an R-value of 5 per inch. A polyisocyanarate SIP has a high R-value of between 5.6 and 7.7 per inch, and is covered with a moisture barrier foil.

Installation of SIP

The SIP is factory made and the builder simply connects them together and cuts spaces for windows, doors, and fixtures. Your insulation expert should check the quality and warranty on the panels. It measures between 1” and 12” thick, and sizes from 4’x 8’ to 4’x24’, but it can be cut into a suitable size and shape. It is quick to install in a new home or rebuild, resulting in savings on time and labor. Cuttings around pipes and fixtures are sealed with a spray foam seal. Building code stipulates that the SIP be covered with a layer of drywall. Although easy to fit, the SIP is not suitable for a repair or upgrade job, but it is best installed with a new construction, remodel, and retrofit, and can be used for the roof, ceiling, walls, floor, and wall cavities. A moisture barrier foil should only be used when there is no other moisture barrier in the wall.

Safety and Health Concerns

There are a number of concerns over the safety and health of SIP. A burning SIP produces toxic fumes and the SIP has a questionable fire rating. Manufacturers address the concern by integrating a gypsum board in the SIP core. Another concern is rodents and bugs that burrow through the panel. The insulation contractor and home owner occasionally treat the panels with an insecticide like boric acid and rodenticide. Humidity must be kept at below 50 percent, overhanging trees trimmed, and planting must be at least three feet away from the wall. Since SIP panels are tightly-knit, the insulation contractor creates ventilation through mechanical ventilators and ducts. Finally, used SIPs have little reusable and recyclable value, and they are toxic when burnt.

Insulating Concrete Forms (ICF)

Insulating concrete forms (ICFs) are poured concrete structures that sandwich a batt, spray foam, or other insulation material, much like the batt insulation. The ICF creates a concrete thermal barrier with a high R-value of 20. The ICF is the main structural material for the house as well. Form boards reinforced with steel rods or rebar are interconnected, interlocked, and tied together with plastic ties, leaving hollow cores for insulation materials. The foam blocks are treated with insecticide and rodenticide, and add a waterproofing compound. Installation of the ICF requires a specially-skilled builder working with an insulation expert. The plastic materials used in the core of the ICF are polyurethane, ESP, and XPS composites. The materials can be compared as follows;

Poly-urethaneEPSXPSEPS Composite
Density (lbs./cu. Ft.)21.3-1.81.6-1.821
R-value per inch5.94.2-4.453
Water Absorption2.00%2.90%0.30%-
Compressive Strength30psi15-33psi25-40psi72psi
Tensile Strength30psi18-27psi45-75psi42psi
Cost/ sq. ft.$0.70$0.17$0.35-
Concrete Block Insulation

The concrete foundation and wall can be insulated by adding an insulating material at the core of the foundation or in the cavities between concrete wall surfaces. The floor has little effect on energy saving if the foundation walls are not insulated too. Exterior insulation has an advantage over interior insulation of containing the heat within the thermal mass. Some concrete blocks have polystyrene beads in them and others have rigid foam inserts.

Autoclaved concrete is ten times more insulation effective than standard concrete. It is also light and easy to shape, nail, or saw through with standard tools. However it easily absorbs moisture and therefore needs to be moisture-proofed. There are two types of precast, solid, and autoclaved concrete block insulation; the autoclaved aerated concrete or AAC and autoclaved cellular concrete or ACC. ACC contains 80 air by volume. Precast ACC contains fly ash, a waste product from burning coal, while AAC contains high-silica sand. A hollow filled wool chippings is also available, but it is not protected from the elements, especially absorption of moisture. Concrete blocks are installed with a new home construction, but an existing home can be insulated from the inside with the concrete block.

Foam Board or Rigid Foam

Foam board is a rigid insulation panel that can be used anywhere in the house. It is suitable for exterior and interior wall sheathing, floor, basement, roof, ceiling, or attic. The common foam board material is the foam bead made from polystyrene, polyurethane, or polyioscyanurate.

Rigid Fiber Board Insulation

The rigid fiber board insulation is made up of fiberglass or mineral wool and mostly suited for insulating high temperature air ducts and pipes. Many HVAC manufactures insulate their equipment with this material. The unfaced board can be finished with reinforced canvas, cement, or weatherproofed mastic. The Faced board can be finished with reinforced material the unfaced board, and their joints taped together to prevent an air leak.

Insulating Concrete Forms or ICFs

An ICF is an insulation option that uses concrete and EPS (expanded polystyrene) materials. It help retain the structural and aesthetic value of the house while giving excellent insulation properties. Moreover, ICF costs just a little more than standard insulation options. ICF are not harmful to the person doing the insulation. Concrete is solid, durable, and dependable. It is fireproof, largely moisture proof, and resistant to wind and other elements. A built-in layer of EPS foam insulation is encased in concrete to improve thermo-insulation properties. Because it is rigid it has a good acoustic quality too. The ICF improves the homes net value by at least 3 percent.

ICF and Building Green

Saving energy in the house is a priority, and ICF is a great alternative and a green insulation type. Concrete has a good R-value and U-value, and a tight fitting joining. It allows for a slower temperature transition because of their thermo-mass, better insulation, and tighter construction than a wood-frame wall. You therefore lower your energy bills and can have smaller heating and HVAC systems. The ICF insulation has a saving of 44 percent for heating and 32 percent for cooling compared to wood frame houses. Generally, you save about $200 in heating costs and $65 in AC costs per year. The heating savings are greater in the cooler climates and bigger houses, while the cooling savings are greater in the warmer climates and smaller houses. In general there are more savings in heating than in cooling. Compared to an insulated wood frame’s R-value of 9 to 15, the ICF has an R-value ranging between 17 and 26. It also has more air sealing, a firmer and stronger structure that is more resistant to earthquakes.

Benefits of ICF

Most home owners who use ICF rank the benefits of ICF as comfort, acoustic comfort, structural strength, and energy saving.

It is easy to insulate with ICF since it integrates the house construction with insulation. Because of greater energy conservation, better temperature regulation, and more energy bill savings of 25 to 50 percent, you get more comfort in the home. The ICF has a high R-value, high thermal mass, no convectional currents, and better air sealing. Energy-efficient construction is booming because of global warming, rising fuel prices, and strict energy codes, and ICF surpasses all the standards. The ICF insulation integrity lasts as long as the wall structure itself.

Apart from a high R-value, ICF also exhibits a low U-factor, superior thermal mass moderation, and reduced air infiltration. This is called the ICF effect. ICF has a constant R-value unlike other types of insulation that perform below their rated R-value. There are many points through which air infiltration into a house occurs, such as sheathing, wall insulation gaps in the cavity, penetration at the balcony, cantilever floor, humidity, drying of wood frame that reduced the wood’s volume, and so forth. The infiltration can reach 0.5 ACH (air changes per hour) or exchange of ½ the house’s air with the external climate every hour. Only ICF has a tight barrier against infiltration. The windows and doors in the ICF home are easy to weather strip.

A heavier mass such as ICF absorbs more heat (heat capacity) and releases it more slowly (thermal lag) than a lightweight mass such as wood frame. With the heat transfer lag, the house is relatively warmer long into the off-peak hours, which incidentally are also the peak demand for heating (night time). With ICF in place you need a small HVAC system, which is not energy-hungry. The regulated temperature allows the home to remain comfortable and livable. There is no cold spot as the insulation is continuous and airtight. ICF homes surpass the Energy Star requirements.

The USDOE lists ICF as a “best practice” in buildings. The ICF construction is stronger than a wooden structure and can withstand a hurricane, earthquake, and fire. Insurance companies offer a discount on ICF-built houses. ICF is a dense wall that creates an efficient sound barrier that is eight times more efficient than the standard wood frame house. ICF houses require less repair and maintenance, and the insulation lasts the lifetime of the ICF wall – which is many decades. Reinforced concrete is durable for centuries since the imbedded steel reinforcement is protected from corrosion. Building and insulating with ICF generates less debris and waste on the construction site. The ICF walls and floor are cleaner and easier to maintain. The plastic foams in the ICF are mostly non-toxic and are sealed tight in the concrete.

Summary of Insulation Materials and Applications

TypeMaterialWhere ApplicableInstallation Methods
Batt and BlanketFiberglass
Slag wool
Natural fibers
Rock wool
Plastic fibers
Unfinished wall
Foundation wall
Between studs, joists, and beams.
Foam board
Foam beads
Unfinished walls
Foundation walls
Specialized skills
Foam Board Polystyrene
Unfinished walls
Foundation walls
Unvented low-slope roof Ceiling
Interior use - ½” fire rated gypsum board
weatherproofed exterior facing
ICFFoam boards/blocksUnfinished walls
Foundation walls
Installed as part of the building structure.
Rock wool
Slag Wool
Open cavities
Enclosed cavities
Unfinished attic floors
Hard-to-reach places
Blown into space using blow-in machine
Reflective systemFoil-faced Kraft paper
Plastic film
Polyethylene bubbles
Unfinished walls
Foils, films, or papers fitted between studs, joists, rafters, and beams.
Rigid fiber insulationFiberglass
Rock wool
Slag wool
Hot pipes
High temperature areas
Fabricated HVAC duct insulation
Sprayed Foam,
Enclosed cavities
Open cavities
Hard-to-reach places
Unfinished attic floors
Pressurized spray can
Foamed-in-place pressure spray
SIPFoam board
Straw core insulation
Unfinished walls
Fitting the SIP boards together

Major House Insulation Projects

There are a number of house insulation projects you can carry out both in the whole house or in individual areas of the house. A whole house insulation project is ideal because it unifies all aspects of residential insulation, but budgetary considerations may compel you to carry out smaller projects in order of priority. The goal is to eventually insulate the entire house and reap the benefits it brings. Individual projects can be the attic or roof, the exterior and interior walls, the floor, the crawlspace or basement, heating ducts and plumbing, and weatherizing the doors and windows. Insulation incorporates moisture or vapor barriers and air sealing.

1. Removing Old Insulation

According to, when upgrading to cellulose, you should remove all the old fiberglass material, since cellulose insulation offers a cleaner environment, and old material may be harboring rodents, mildew, and bugs. Cellulose is mostly made from recycled materials, traps air better, and is treated for molding, bug infestation, and fire. However, removing foam insulation is an expensive undertaking, costing between $1 and $2 per square foot. Installing the cellulose will cost between $0.9 and $1.3 per square foot of materials and $1 per square foot of labor. A project to replace fiberglass with cellulose insulation will therefore cost between $2.9 and $4.2 per square foot.

2. Moisture Control

It is important to include moisture control in the insulation project. Moisture makes the structure less thermal-efficient, moldy, humid, and uncomfortable. It also improves air sealing. The strategy for moisture control depends on the climate you live in. in all cases, you need a proper ventilation that reduced condensation while maintaining thermal insulation. Moisture enters the structure in three ways; diffusion, air-borne, and through heat transfer.

Air currents or movements account for 98 percent of water vapor movement, which quickly infiltrates into the house through cracks, gaps, and any openings. A warmer air carries more moisture –high relative humidity – and releases it as it cools. Diffusion and heat transfers act more slowly, especially through the building materials. Insulation helps to stem heat transfer, and air movement should only be through ventilation.

Apart from air-borne moisture, infiltration can occur through the foundation and below-grade walls of the basement, crawlspace, and slab-on-grade foundation. For measures to control basement moisture, refer to our article on “Basement Remodeling Costs”. The cracks, crevices, joints, and porous materials have to be moisture insulated from the exterior and from the interior, and the work is best done by a building contractor rather than the insulation contractor.

Wall moisture is cause to a large extent by capillary action and air-borne moisture, and only a small amount is through diffusion. Vapor retarders should include vapor barriers at grade level using polyethylene ground cover and a sill gasket against capillary action up the wall. A termite shield will protect the polyethylene sheet from termite burrowing. The wall surface should be insulated with a vapor retarder and weather stripping, and proper flashing against rain and air-borne moisture.

3. Vapor Diffusion Retardation

Prolonged exposure of the house structures to moisture leads to dampening, reduction in thermal insulation, wood rot, and molding. For insulation to be effective, the surfaces have to be vapor-proofed. A vapor diffusion retarder is installed on the warmer side of the house, that is; the interior side in cold climates or exterior side in warm climates. It is used to control moisture in the basement, crawlspace, on floors, walls, ceiling, and the slab on the grade foundation.

The ability for materials to resist moisture diffusion is measured in Perms. Vapor diffusion retarders are classified as Class I, Class II, and Class III. Class I retarders, which include glass, rubber, sheet metal, and polyethylene sheet, are the most vapor retardant with a diffusion of 0 to 0.1 perms. Class II retarders have a diffusion retardation of between 0.1 and 1.0 perms and include asphalt-coated paper, bitumen-coated Kraft paper, plywood, and unfaced EPS or XPS. Class III retarders have a poor diffusion retardation of between 1.0 and 10 perms. They include gypsum board, lumber, concrete block, house wrap, cellulose insulation, unfaced fiberglass insulation, and bricks.

Vapor diffusion retarders can be either membrane or coating types. Membrane retarders are usually thin and flexible materials, although some are rigid. Examples of vapor diffusion retarders are polyethylene, fiberglass roll insulation, stainless steel, foil-backed wallboard, reinforced plastic, aluminum foil, and rigid foam insulation. They are fastened and sealed at the joints.

Coating vapor diffusion retarders are paints with moisture resistance properties. Glossy and acrylic paints are better vapor barriers than flat and latex paints. For tough areas, apply an extra coat of vapor diffusion retardant paint. Application should be even and continuous over the cracks, tears, punctures, openings, and uneven surfaces. Gypsum board is highly absorbent of moisture, and it is usually painted with a waterproof paint. Over time, paint cracks, peels, and breaks down because of exposure to the elements like UV, moisture, and heat. Coating vapor diffusion retarders are not suitable for repair work, but can be used in new construction and remodeling projects.

4. Sealing Air Leaks

Air leaks contribute significantly to heat loss in the house. The air flow in and out of the house adds about $350 to the annual energy budget. It is possible to plug all air leaks with less than that amount. The attic is exposed to a lot of air flow and empty space. The basement allows cold air to flow up the stairs to the main house. The main house has several air leak points including; the window and door frames, recessed lights, stud cavities, flue and chimney, skinny gaps, basement gaps, and attic access door, and medium-sized gaps.

Draughts occur around door and window openings. Caulking and weather-stripping go a long way in insulating these gaps. Some of the common weather-stripping materials include bronze at a cost of $1 to $5 per linear foot, adhesive EPDM rubber at $0.8 per linear foot, pulley seals at $9 a pair, and a door sweep at $9. Small skinny gaps of less than 1/4” wide, for example around electrical boxes, can be filled with caulk which costs $8 for a silicone tube. It is ideal where the flashing is metallic or temperatures are extreme, for example in the attic.

A cheaper and cleaner to install alternative is the acrylic latex caulk at $2 per tube. Medium-sized gaps of up to 3” in the plumbing pipes and vents can be plugged with a low-expansion polyurethane foam. A 12oz can cost $5 and can cover 250 feet bead at ½” thickness. When the attic access door has gaps of 1/4” around it, they leak in as much cold air as the bedroom heater duct. Add caulking or do weather-stripping to seal the gaps around the perimeter frame of the hatch opening. You can still install a pre-assembled attic hatch cover for between $150 and $350.

Most houses have stud cavities of drywall or plaster between the living room and unheated areas. Seal such cavities with unfaced fiberglass insulation stuffed in plastic garbage bags at a cost of $0.75 per square foot. Large gaps can be filled scrap drywall and reflective foil insulation at a cost of just $2 per square foot. The metal flue is separated from the chimney by a 2” gap and from the wood framing by a 1” gap. The gaps can be covered with aluminum flashing at $12 and high-temperature silicone caulk at $14. Wrap the flue pipe with a flashing foil supported by inch deep spacers or tabs.

Recessed lights have vents that open into the attic and an ordinary house will have between 30 and 40 such recessed lights. Install airtight baffles, which cost between $5 and $30 apiece and take a few seconds to fix as a DIY. You just have to remove the bulb, push the baffle firmly into the housing, and replace the bulb.

Plug the gaps found in the basement. The gaps above the ground level can be sealed with high temperature caulk and spray foam. Seal the vent and plumbing pipes with a high temperature spray foam. In the older house, apply a bead of caulk between the foundation and the sill plates, and along the bottom and top edges of the rim joist.

5. Creating Air Barriers

Air in the warm climates is more humid and when it leaks it increases heat loss and molding. The insulation contractor needs to repair and seal small air leaks using caulk, foil tape, or polyethylene. Air barriers/vapor retarders are applied around the building under the exterior finish or they may be used as the exterior finish itself. The materials used as air and vapor barriers are foam board insulation, builder’s foil, polyethylene plastic sheet, and other exterior sheathing. You can look up information about insulation material that are also moisture and vapor barriers from such websites as;

6. Weather Stripping explains that weather stripping helps to keep out cold draughts through the door and window. Inspect the doors and windows for worn out weather stripping. The stripping is worn out by friction, pests, rodents, pets, ageing, and the elements. Rubber and vinyl become brittle and cracked over time. Spring-loaded weather stripping bends out of shape and tears at some spot. And the self-adhesive foam tape loses its stickiness because of dust and ageing. Foam also loses its elasticity and bends out of shape because of the elements.

Before installation, the surface to be weather stripped is smoothed with fine-grit sandpaper, cleaned, dried and vacuumed. Old nail or screw holes are filled and sanded.

To remove the old weather strip, the insulation contractor will peel off stripping by hand. If fastened, he will unfasten or use a claw nail to remove the nails. Decide on the best weather stripping option, bearing in mind that the cheapest or easiest installation are often the least effective and have a short lifespan.

Adhesive-backed foam tape costs less than a dollar per foot and the installation is just as easy as cleaning and drying the surface, close the window sash against the sill or door against the frame, peeling off the seal from a new weather stripping, and sticking it on the surface. The weather stripping has a 3 to 4 year lifespan.

A peel-and-stick V-shaped vinyl, which costs just over $0.50 per foot, is installed by simply peeling and sticking. It has 3 year lifespan at best. Bronze and copper stripping will cost $2 per foot, have to be nailed down, and will last much longer.

The V-shaped weather stripping or tension-seal weather stripping is suited to the side channels of a tight door or a double-hung window.

Vinyl gaskets or tubular rubber are good weather stripping materials, especially for irregularly-shaped surfaces. The hollow is elastic enough to cover a big gap or to be compressed into a small gap. The vinyl and rubber weather stripping are nailed or fastened in place and they cost between $0.90 and $1.25 per foot.

Some peel-and-stick stripping can only be applied when the temperature is above 50 degrees Fahrenheit. Ensure the stripping is correctly placed to allow the door or window to close properly. Measure accurately before cutting because too short a strip is discarded and too long a strip is cut away and wasted. Use the correct cutting tools; snips for metal strips and utility knife for rubber and vinyl. The opening of the V-shape faces towards the elements in order to stop moisture getting into the house.

When installing the adhesive type of weather stripping, peel the backing off bit by bit and press against the surface until the whole strip is done. When installing the fastened type of weather stripping, pre-punch holes through which you will drive the nails or screws. For double hung windows, install the lower half weather stripping, then drop the sash, and finally install the upper weather stripping.

Attic and Roof Insulation

The attic is a major areas for heat loss in the house and therefore needs to be looked at keenly. It has a large space between the roof and the ceiling that allows free flow of air. An uninsulated attic and roof can cause as much as 25 percent of the total heat loss in the house. Insulation of the roof and attic is a massive but simple task and an installed insulation can last many years. You have to control moisture and air leakage first.

DIY or Pro

The decision to DIY or engage a pro for attic insulation depends on a number of factors besides budget. For an attic with a simple design, no hard-to-reach spaces, and an uncomplicated roofing, or has no moisture problems, such as leaks, dampness, mold, and vapor, then you can DIY using blanket and batt, laid out in layers between joists. The first layer is placed between joists, while the second layer is laid at right angle to the first layer and covers the joists as well to make the required depth of insulation.

Where it is not easy to identify all the areas of heat loss and the relationship between roofing materials, heat loss, and ideal insulation material to curb it, it is better to leave the task to an insulation contractor near you. If you choose to use spray foam and blown-in insulation or if you have to work around crooked spaces, install ventilation, control moisture, or insulate a flat roof, then must use an insulation pro.

Methods of Attic Insulation

There are four main ways of insulating the attic, namely; roll-on blanket, loose fill or blown in insulation, sprayed foam, and radiant barrier/reflective insulation.

1. The roll-on or blanket insulation comes in large rolls of batts made from fiberglass measuring between 15” and 23” wide to fit between framing. It should not be compressed as this would reduce its effectiveness. If repairing an existing insulation, then place the insulation over the existing insulation and framing at right angle.

2. The loose-fill or blown-in insulation is an insulation that is made of loose fiberglass or cellulose fibers that are blown into the attic floor framing. The material can easily fill crevices and hard-to-reach areas. A machine is required to carry out this job.

3. The sprayed foam polyurethane insulation is suitable if the attic is going to be converted into a full-time use room such as a bedroom, in which case you need to insulate the roof rather than the floor. The spray foam is able to fill and level the space to the rafters, can block the water vapor, and has a high R-value per inch. The spray foam costs about twice as much as the blown-in and roll-on insulation.

4. A radiant barrier reflects summer heat back into space and keeps the house cool, while reflective or thermal insulation

absorbs internal heat and reflects or radiates it back into the house, and keeps the house warm. The reflective material of choice is aluminum foil with a backing such as Kraft paper, polyethylene bubbles, plastic film, or cardboard, and thermal insulation. Radiant barriers can lower the summer cooling costs by between 5 and 10 percent. Most insulations are designed to resist moisture and heat transfer by conduction and convection.

Moisture Control

Moisture control in attic insulation is strictly a professional insulator’s domain. While insulation traps warm air in the living space, which keeps the attic cooler, it makes the attic and roof susceptible to condensation. The insulation pro therefore will curb the dampness by creating adequate ventilation away from air draughts.

Choosing Attic and Roof Insulation

A properly done attic and roof insulation will bring such benefits as;

  • Create a comfy living space at minimal energy cost
  • An efficient energy retention and distribution in the house, leading to lower energy bills
  • Improve the efficiency of the HVAC and water heating systems
  • Create an acoustic barrier from both external and internal noise
  • Help create a healthier environment free from dust, mold, and cold
  • Choosing the right insulation will depend on the use of the attic space

1. Insulating for a storage space

If the attic is used for storage, then you need to insulate between the joists with blanket and batt, and then cover with insulation boards over the joists. In order to achieve the correct R-value, make sure the boards are not pressed against the inner insulation. The insulation will not be as effective as a non-storage attic, but you can increase the depth of the floor by a few inches using battens across the joists or plastic legs that support the floating floor. Leave a ventilation gap below the boards to prevent condensation on the underside.

2. Insulating for a living space

If you want to upgrade or convert the attic into a living space such as bedroom, study, or children’s play room, then you should insulate the roof instead. Use rigid insulating boards that are cut to size to fit snugly between roof rafters, and cover the insulation and rafters with plasterboard. Since the roof and rafters are not deep, you should insulate between the rafters and roofing itself using high performance plasterboard or spray foam insulation. The attic walls and gaps are also insulated using plasterboard or spray foam insulation.

3. Insulating in awkward space

If the attic is hard to reach in places, then you should opt for blown-in insulation or spray foam insulation, done with special equipment and by an insulation contractor near you. The blown-in material is loose and made of cellulose fiber, mineral wool, or fiberglass, and should include a fire retarder. The spray foam insulation is more expensive to install than the blanket and batt insulation, but faster to carry out by a professional. Provide for ventilation that will prevent condensation under the roof. The windows should be weatherized and any significant gaps caulked or spray foamed.

4. Insulating the flat roof

If the roof is flat, then you should insulate from the rooftop using rigid insulating boards either on top of or below the weatherproofing layer in order to avoid condensation underneath the roof. You need to remove the roof finishing first. However, if you choose to replace the roof itself, then do the insulation from inside, between the rafters and the roofing material. Insulating from below the roof however raises the risk of condensation under the roof. Insulating the flat roof can be as beneficial in energy saving as insulating the attic itself.

5. Attic hatch, tank, pipes, and ducts

The attic hatch needs to be weather stripped in order to reduce air leaks. Ducts, pipes, and water tanks in the attic need an insulating jacket in order to prevent dampness in the surrounding joists.

Cost of Insulating the Attic

You need to find out how much insulation you require in your house by subtracting the installed amount from the recommended amount of insulation in your area. You can also check out the Home Energy Saver at You can lower your heating costs by as much as $600 per year when you boost the attic insulation from R-11 to R-49, according to The standard labor cost for insulation is between $1.00 and $1.80 per linear foot. The insulation contractor will charge you about $1,500 for an 800 square foot attic. According to, the cost of insulating the attic can be broken down as follows;

Type of InsulationDetached houseSemi-detached houseMid-terrace houseDetached bungalow
New Attic (12” deep)
Energy Saving per Year$300$190$170$270
Installation cost$550$400$400$520
CO2 Saving per Year2180– 2,690 kg1300– 1,590 kg1,170– 1,410 kg1,870– 2,310 kg
Additional (6” to 12”)
Energy Saving per Year$30$140$140$200
Installation cost$290$340$320$400
CO2 Saving per Year200– 240 kg110– 155 kg110– 130 kg180– 200 kg

7. Solid Wall Insulation

The solid wall can be insulated internally or externally. The internal insulation is done using either rigid insulating boards or stud wall. The stud wall is thicker and strong enough to hold heavy fittings like racks, kitchen units, wash basins, and so forth, unlike the insulating board that needs fixing to the wall behind it. The insulating plasterboard is made of a 4” thick, foamed plastic. It is attached to the wall by an adhesive. The joints at joists are sealed to stop air leaks. Whichever method is used, the wall surface must be even and smooth and if not, it is leveled with a layer of insulating plaster.

The stud wall is a wooden or metallic frame fixed to the wall and filled with fiberglass. It is then plastered over and redecorated. Fiberglass insulation is less effective than insulation board. For a more effectiveness, the stud frame can be cover with insulating boards instead of plaster.

Preparing for Internal Insulation

Internal insulation disrupts the lives of the house occupant for the duration of the project. The external wall’s heating, plumbing, cornices, coving, and radiators have to be repositioned in a flush manner. Skirting boards and door frames will be removed for later reinstallation on the “new wall”. The windows have to be weather proofed with weather stripping. The installers will ensure the house conforms to the building code.

When insulating solid walls, use materials that have breathing spaces or vapor permeable materials, which helps to reduce moisture build-up, otherwise the insulation contractor can recommend measures to take to avoid the build-up when using vapor impermeable materials.

Insulating the Wall Cavity

A third of household heat is lost through the walls. Insulating the walls can save up $220 per year in energy bills. During winter, heat quickly dissipates into the atmosphere through the walls. There are two types of wall; solid wall and cavity walls, and cavity walls have the most effective saving when insulated because trapped air is a good insulator. The cost of insulation is around $350 and foam and fiberglass are the materials of choice. Old houses have solid walls unlike modern houses that have cavity walls. There non-standard wall types like prefabricated iron and solid wood.

The wall cavity insulation includes spray foam or blown in and it can be done from the outer side or inner side of the wall. The insulation of the wall cavity is recommended if the wall cavity is at least 2” thick; external walls do not have cavity filling; the brickwork and masonry are still new; the existing insulation is more than 20 years old; the walls do not experience stormy weather; and all piping, ducts and vents pass through the crawl space. You should control moisture leaks before doing the insulation. Materials used for the cavity insulation include mineral wool, polystyrene beads, and sprayed foams.

Solid Wall vs. Cavity Wall Insulation

A cavity wall is already twice as efficient as a solid wall in conserving heat. The solid wall does more heat conduction, while the cavity is filled with air pockets which act as insulators. The solid wall is insulated from either the interior or the exterior side of the wall. Cavity walls are insulated along the cavities. External insulation is cheaper than internal insulation and does not eat into the house’s footprint. The cost of insulating a solid wall is lowered if you do it alongside a new construction, remodeling the house, or retrofitting. External wall insulation is less disruptive to the house occupants, and can be reinforced by a project such as solar panel installation.

Internal vs. External Insulation

In internal insulation, the wall is fitted with a rigid insulation board or by building a stud wall and filling it with fiberglass insulation. The external insulation involves applying layers of insulating material and rendering it with a special plasterwork or cladding. The finishing can be textured, smooth, brick, pebble-dash, paneling, tiled, and so forth.

Internal wall insulation
Cheaper to installReduces floor area by about 4” from wall
Can be done room by roomLess efficient
Good acoustic barrierDisrupts the house occupants
Requires moisture problems solved first
Difficult to fix heavy items to the inside wall
Detach and reattach skirting boards, door frames, window sills, fittings
External wall insulation
Does not disrupt house occupantsRequires building permit
Does not reduce floor areaMust be done all at once
Refreshes the looks of the houseRequires access to the outer wall
Installed with remodeling, cost saving
Reduces condensation on internal wall
Enhances weatherproofing
Extends lifespan of the external wall
Prevents air leaks through gaps and cracks

8. Crawlspace Insulating

The crawl space is underneath the house and can easily be the culprit when you experience cold feet in the house even after insulating it. The choice of insulation depends on whether the crawl space is ventilated or not. Building code requires that you have vents for removing moisture from the crawlspace, but when the moisture is dried out, it is best to close the vents and instead use moisture-control measures and exterior drainage to keep the crawlspace dry and insulated. Where they exist, vents are closed during winter to keep the crawlspace warm, and during summer to keep out warm, humid air.

You will then air seal and insulate the foundation walls rather than the floor. This measure helps to avoid having to insulate both the walls and the ducts/pipes since the ducts/pipes will be at par condition with the crawlspace. Create an access door to the crawlspace inside the house, through the subfloor, rather than the exterior foundation wall.

Unconditioned Crawlspace/Basement “Roof”

The house floor is conditioned and finished on the topside but unconditioned on the underside. Install the insulation in the cavities and gaps between the joists above the crawlspace (“roof” of the crawlspace). Ensure the installation is not misaligned between conditioned and unconditioned space. Do not compress the insulation as this would cause it to result in unfilled spaces and affect its R-value. If you leave in a cold region, then seal the entire crawlspace and insulate around the foundation walls or supports.

Air sealing will reduce moisture, humidity, and cold air circulation, and void the need for stringent in-crawlspace insulation. When you use Kraft-faced batts, then the paper has to face the warmer side of the cavity; that is, in-facing for cold places, and out-facing for hot places. You will finally control termites, rodents, bugs, and pests, which damage the insulation and foundation structure, especially wood, polyethylene, rubber, and any other soft material.

Crawlspace Wall

The foundation walls of the crawlspace are susceptible to moisture from underground, rainwater, and moisture in the air, and attacks from rodents and bugs. Place a 6-mil vapor diffusion retarder on the crawlspace floor. Then install a sill gasket between the foundation wall and band joists, followed by a vapor retarder membrane down the interior foundation wall. Finally, seal all band joists, crawl access, and leak holes or spaces with R-11 to R-19 batt insulation or rigid foam board. If you have a combustion furnace, HVAC, or heater in the crawlspace, be sure to install a powered, sealed combustion unit. Install a perforated and filtered drain pipe out and below the floor level of the crawlspace and cover it with gravel. Treat the crawlspace with a termite shield between the masonry foundation and band joist. Install a supply outlet for return air passage.

Ventilated Crawlspace

When insulating a ventilated crawlspace, you need to first seal all holes or gaps in the floor above to prevent any air draughts from entering the main house from underneath. Use rolled tightly packed fiberglass batt and fasten it between joists. Seal all seams and use either a house wrap or a faced vapor barrier to cover the insulation and retard any vapor from below. Install a covering of polyethylene vapor retarder on the crawl floor, tape, and seal its seams. Optionally, you can spread a thin layer of sand to hold the covering down.


For any obstructions like ductwork, connectors, HVAC boots, vents, water pipes, gas lines, wiring and support bracing, wrap the obstructions with some cut insulation. Insulation at electrical fixtures and outlets or hot places such as furnace, hot water pipes, and heaters must be insulated with fire-rated materials as required by the National Fire Protection Association or NFPA and the International Code Council or ICC for building code.

The clearance between insulation and heated appliances, chimneys, recessed lights and other hot surfaces must meet the most stringent requirement by the manufacturer, National Fire Protection Association or NFPA, International Code Council or ICC, or the building code.

9. Duct/Pipe Insulation

Pipes, ducts, and vents are made of different materials, which require different types of insulation, therefore, a comparison of insulation types can only be based on general characteristics of the piping and the insulation such as heat characteristics, structural strength, pH tolerance range, corrosion, fire rating, and moisture permeability. For example, PVC pipes have a lower temperature tolerance but are non-corrosive steel is corrosive but structurally strong. Rubber is flexible and air tight, but it is easily damaged by heat, corrosion, and acidity. The purpose of insulating the pipes is multi-fold;

  • Managing the rate of heat loss
  • Keeping the pipes stable and safe when moderating the temperature.
  • Reducing the surface temperature of pipes to a safer level
  • Retaining as much heat as possible within the heating system
  • Preventing condensation and corrosion on metallic pipes
  • Retarding fire, especially by using fiberglass and mineral wool insulation
  • Controlling the vibration and noise level from pressurized water, gas, and steam
  • And reducing the cost of heating

When choosing the insulation it is important to match the characteristics of the pipe material with characteristics of the insulation material. Rigid insulation is suited to sturdy pipes like steel; fiberglass and mineral batts are suitable for most types of piping; and loose-fill insulation is not suitable for pipe insulation. Since the pipes are located in tight spaces, it is good to choose a high R-value insulating material, such as mineral wool and fiberglass insulation.

Fiberglass duct insulation comes in three main varieties to suit the heating system and optimize the house energy savings. The fiberglass duct liner comes in form of a blanket or board in different thicknesses and densities coated with a fiber mat. It is used for thermal and acoustic insulation, fastened around the metallic duct. The fiberglass duct board system is one that is assembled

into a complete air duct using a rigid insulation board of Kraft paper or aluminum laminate. It is both as an air barrier that prevents condensation and insulation that prevents heat conduction through the duct wall. And the fiberglass duct wrap is a flexible and laminated blanket that covers irregularly-shaped duct sections. It is a vapor retarder and thermal insulation.
When the duct/plumbing passes through the subfloor, the joists should be deep enough to allow routing and space for underside insulation. The ducts should be insulated with a continuous insulation and then laid on a rigid board insulation, which is also covers the joist bay.

10. Floor Insulation

If you find the floor a tad bit too cold despite the house being insulated, then it may be that the floor is either not properly insulated or its insulation needs repairing. 15 percent of house heat is actually lost through the floor. Air may pass through gaps or cracks between floor boards and joists. Most floor structures are made of wooden type although some are made of concrete. There are several floor insulation materials to choose from and your insulation contractor can advise you according to the kind of floor you have.

Benefits of Floor Insulation

Floor insulation reduces air flow through the floor and into the house. When properly done, floor insulation forms an air and vapor-tight seal against infiltration from the grade. The savings on annual heating costs for the average home can reach $150. It also helps to preserve the structural integrity of the house and keep its ROI high. Proper floor insulation and pest control is covered by insurance and qualifies for rebates and tax credits. Floor insulation helps to reduce carbon emission by about 350 lbs. per year because there is less demand for heating fuel, electricity, and dam water for electricity generation.

Thermal-Efficient Floor states that fiberglass is not highly rated for floor insulation, especially because of the difficulty of air sealing awkward regions of the floor. Spray foam insulation in the subfloor performs better.

Air sealing is part of the floor insulation, especially when the floor is raised from the grade or is between floors. A continuous layer of rigid foam on the underside with caulking or 3M all-weather house taping around its rims ensures a uniform air seal, hence better insulation, especially when used with cellulose or fiberglass batt. According to, you should ensure that the R-value for your floor meets the local recommendations of the International Residential Building Code and that air sealing, moisture control, and insulation comply with the Thermal Bypass Checklist of an Energy Star house. In the US, the recommended floor R-values for the different zones are; R-13 for zones 1 and 2, R-19 for zones 3 and 4, and R-30 for zones 5 and 6 and the marine zone 4. The U-value should be below 0.25 in most zones.

Subfloor Insulation

The main problem with subfloor insulation is accessibility and lack of space for the insulation itself. With limited floor depth, you have to opt for a high R-value, densely-packed, and more expensive insulation material. Pipes and ducts make floor insulation more complicated. Fiberglass is the material of choice in such floors because it is stable, long-lasting, and fire resistant. You have to install a moisture barrier beneath the subfloor insulation.

Foundation Wall Insulation

Where the house has a basement or below-grade crawl space, you need to insulate the foundation wall as well. You also have to control moisture leaks, rodents, termites, and bugs, which can damage the floor.

Basement Insulation

The basement needs special care to insulate. Most basement heat loss occurs due to moisture infiltration on the walls and floor, and cold air drafts from the staircase above. Proper insulation aims to keep the basement permanently dry and well ventilated. Drainage is particularly challenging because the space is below grade (for a clearer picture of the problem, read our article on basement remodeling costs). The properly insulated basement can save up to 10 percent on heating costs, and any type of insulation is considered practical. ICB and ICF are suitable only for new construction insulation, but other types of insulation are fine for repair and insulation projects, for example batt and roll, foam board, loose-fill, and spray foam insulation.

The most effective basement insulation is the one installed on the exterior walls and basement floor in either a new construction or a major basement remodeling. The insulation acts as a barrier to thermal bridging. Use a moisture barrier, such as polyethylene sheet on the exterior and damp-control paint on the interior drywalls after back filling. In order to reduce temperature swings, make the foundation floor part of the thermal mass of the conditioned space. Use radiation foils to reflect heat back into the basement. Install dehumidifiers to minimize condensation in the basement. Again, since the basement is below grade, install a fire rated covering in case of a fire emergency.

Underfloor Insulation

The insulation of the underfloor can be done from underneath the floor where there is a basement or crawlspace, garage ceiling, or a cantilevered bay. You should install the underfloor insulation when constructing a new house or doing a major remodel. Ask the building, electrical, and plumbing sub-contractors to leave room in the joists for insulation work. You should run the plumbing and ductwork beneath the insulation in order to have a continuous insulation installed, but if the region gets very cold winters then consider wrapping the pipes, drainage, and ducts with insulation. Ensure a complete air barrier and air leak are properly sealed, and pay special attention to duct boot, bath tab drains, ductwork plenums, electrical outlets, between the band joist and floor, and other gaps.

The main floor insulation should run the full length of the joists and the second layer should be flushed to the joists for a more efficient insulation and air seal. Where need be, you can cut slits in the insulation roll to make room for obstacles. Use insulation hangers or wire staves at 12” to 18” intervals, but make sure it does not compress the insulation. Vapor retarders should be installed on the warmer side of the house; either on the exterior in warm climates or interior in cold climates. If the ductwork and plumbing are encapsulated within the crawlspace or garage, then they do not have to be insulated. Keep the crawlspace dry at all times in order to prevent floor condensation, termite infestation, and mold formation. If insulating the truss floor, add a loose net or foam board on the underside to hold the insulation in place without compressing it. You can fill the space left between the insulation packs with a loose-fill insulation.

Underfloor insulation can save up to $90 per year in heating costs. It costs about $1,200 to $1,850 to insulate the underside.

Slab-on-Grade Insulation

The house is supported on slabs, which are therefore a source of heat conduction between the house and the grade. A cold slab can cause discomfort in form of a cold wall base. An insulated slab is easier to heat and retain the heat, and it can save between 10 and 20 percent on heating energy.

It is easier to insulate the slab using foam boards during construction. The foam board insulation encloses the slab exterior and footing. In order to protect the slab, the insulation expert will treat the area around the slab with insecticide and anti-termite chemicals. They will also control moisture with a vapor diffusion barrier.

Wood Floor Insulation

The wood floor is often ignored by home owners when they do insulation, and new owners of old houses may not be aware of the anomaly until the cold winter strikes or they decide to remodel the floor. You may have to add radiant floor heating when insulating such a floor. Creating and maintaining a vapor barrier is important for any floor, but a wood floor is especially susceptible to water damage. Unfaced batts are the best idea because, while you can use faced batts, this type of insulation is harder to keep up and doesn’t have rigid ends. Any loss of integrity will break the vapor barrier and make your wood floor insulation and the floor itself vulnerable to ground moisture. The batting can be held in place with thin metal rods or stave wires. Spacing the rods every 18 inches are the easiest way to hold your insulation in place. You can use plywood or lattice boards, but this will cost more for only slightly better performance. You can also use netting, but this can be a lot of work.

Floating Wooden Floor

Here, the floor sits on top of the joists. They are easy to insulate by fitting rigid insulation boards between the joists. First check to see if ant joists are rotted and need replacement. Hold a sagging net to over the joists to hold the insulation boards from falling through the joist cavities. Cut the larger insulation board into pieces that fit snugly between joists. Working from the beneath the floor, tap them in with a mallet and if they do not fit in well fasten them with battens. Lay another insulation, a blanket roll insulation, at right angles to the joists. Replace the floor boards as before.

The cost of installing a floating floor insulation with fiberglass batt and blanket will cost about $0.90 to $1.45 per square foot of floor. The insulation contractor will charge about $0.80 to $1.20 per square foot. Expect to spend about $2,500 on floor insulation for a standard floor area of 1200 square feet.

Solid Floor Insulation

Concrete floors are mostly insulated at the time of constructing the house as per building regulations. You need to first vapor-proof the floor with damp proof membrane, followed by sheets of a rigid and compact insulation material on the subfloor. Popular materials include gypsum board and polystyrene insulation boards. Ensure that no gaps are left uninsulated. The insulation can be placed either above or below the floorboard. When insulation is installed above the concrete, the room will heat up more quickly during the day, but when installed below it the room will stay warmer for longer during the night. Complete the installation by covering the insulation with the floor finishing, for example the chipboard. Install the rugs and carpets if available, they too have a good insulation capacity. Your room will lose a few inches of floor-to-ceiling height, so you need trim the door shorter and raise the skirting boards. You may also have to move some electrical wiring and sockets. The installation will involve large areas being worked on at a time, which definitely requires professional help from an insulation contractor.

Insulating the solid floor will cost about $1.40 to $1.90 per square foot in materials, and $0.70 to $1.00 in labor. The total cost will come to around $3,500.

Cold Floor Insulation

If a floor is well insulated on the underside, it will stay warm on the inside, but unfortunately many floors are poorly and casually insulated with fiberglass batt on the underside and OSB on top. The badly insulated areas include the post foundation, cantilevered bay, and garage ceiling. If the batts between the joists are not thick enough and fastened to the joists, they have a low R-value and they may fall through the subfloor. Such a floor is very cold during winter and can even result in frozen pipes.

Unconditioned above Garage Floor Insulation

If the garage is below an upper room, aka bonus room, then it is necessary to insulate it from below, in the garage. Seal all air leaks above the garage, and add air barriers especially to prevent carbon monoxide infiltration. If the garage ceiling extends

beyond the floor of the room above then you need to install rigid foam or 2 lumber blocking between the joists in the extended

ceiling. Seal the blocking perimeter with caulk or spray foam. Proceed to insulate the floor as you did in the main house. Insulating the floor above the garage is important because it keeps out cold draughts from an open garage door and unwanted car fumes and solvent from the garage.

Cantilevered floor Insulation

The cantilevered floor is insulated using blocking between joists, above and interior side of the bearing wall. Seal the perimeter of the blocking with an air leak seal such as spray foam or caulk. The insulation is done with rigid foam between joists and secured to the subfloor using an adhesive. Next you will insulate the joist bays with dense-packed cellulose or fiberglass batt insulation. On the underside of the floor, install a continuous rigid foam and fasten it to the joist. Protect the insulation with drywall, OSB, or soffit material.

Insulation Safety and Health

Building materials are expected to be safe and not cause ill-effects on health. Insulation materials are expected to be equally safe and healthy.

Fire Safety

Some materials used in insulation are flammable and require fire retarders. Fiberglass and mineral wool insulation are noncombustible and are even considered to be fire retarders. Kraft paper is combustible but are safe when used with a fire barrier and are not exposed. According to the Consumer Product Safety Commission, cellulose insulation, which is made of paper and wood fibers, is a fire hazard however well-treated it is. Spray foam insulation has a fairly high resistance to flaming, at 700 degrees Fahrenheit. A perimeter fire barrier system should be installed in the space between the exterior curtain wall and edge of the floor.

Indoor Air Quality (IAQ)

The quality of air diminishes as the house is sealed off from the external environment. It is necessary to control the internal pollutants such as household chemicals, preventing external pollutants from getting into the house, and proper use of potentially hazardous products in the house. Controlled ventilation ensures bad air is expunged from the house and clean air drawn in.

Health Impact of Insulating Materials

Among insulating materials, fiberglass is the most rigorously tested for cancer, toxicity, carcinogen, and so forth. Mineral wool is considered safe when properly applied. About 10 percent of fiberglass insulation contains formaldehyde, raising concerns among users. The levels of this substance is however very low to have a serious effect. Cellulose produces the most dust particles or cellulose fibers, although their harm to health is not classified. Spray foam insulation is not fully evaluated, but it does contain toxins like methylene diphenyl di-isocyanate, which affect the lungs and trigger asthma attacks. Most insulation materials stabilize and cure upon application and therefore pose little danger to home occupants. Most danger is found in the installation.


Mold occurs where there is a humid or moist environment with micro organic substances, including the house walls, floor, ceiling, and roof. Fiberglass, mineral wool, and spray foam insulation are inorganic and therefore “resistant” to mold growth. Cellulose insulation is made of organic material and therefore can attract mold when humid. A chemical mold inhibitor can be sprayed on the cellulose insulation.


Corrosion occurs on metallic surfaces like pipes, wires, and fasteners. Most insulation materials except cellulose insulation are non-corrosive. Cellulose insulation contains some metallic materials, fire retarders, and sulfates, which can corrode.

Environmental Considerations

1. Materials

With a good insulation, comes environmental benefits apart from reduced energy use. Insulation helps to curb noise levels and emission of gases. It helps in recycling and reusing, water conservation, among other benefits. The materials used in insulation have a different impact on the environment as outlined below.

Fiberglass is made from recycled glass and sand, which are plentiful, and has a 40 to 60 percent recycled content. Used fiberglass insulation materials can be reused.

Mineral Wool is made from rocks such as basalt, slag from blast furnaces, and diabase. Rock wool has a 10 to 15 percent recycled slag, while slag wool has a 70 to 75 percent recycled blast furnace slag, and they are both reusable.

Spray foam is made from a blend of chemical and mineral compounds like polyols, isocyanates, blast furnace slag, and basalt, among others. Used sprays cannot be recycled.

Cellulose is made from recycled paper and wood fibers which make up 80 percent of the material. It is not reusable, but it easily biodegrades.

2. Embedded Energy in Insulation Products

Embedded or embodied energy refers to the amount of energy that was used in the manufacture of a product. Products that are awarded the coveted “Green Seal” for architectural standards often have little embedded energy. Although some manufacturers advertise their products’ embedded energy, it is not recognized by any standards body because there are many complex factors involved.

3. EPD on Mineral Wool Insulation Products

Environmental Product Declarations or EPDs give information about the environmental impact of loose-fill mineral wool and mineral wool board insulation products throughout their life cycles. The EPDs do not show all certifiable benchmarks.

Residential Insulation Codes and Standards

There are many residential building codes and standards that also affect how you do house insulation, according to NAIMA. NAIMA Energy Code Compliance Guides explain the requirements for 2009 and 2012 International Energy Conservation Codes (IECC), as legislated by each state. So you can easily reference the requirements for energy-efficient residential construction in your area. The International Energy Conservation Code that affect insulation and energy efficiency are contained in their website,, are;

  • Window, door, and skylight SHGCs and U-factors to meet air infiltration standards, must be set forth by the National
  • Fenestration Rating Council or NFRC, and are indicated on all building glass products.
  • Insulation R-values are only minimum acceptable values.
  • The R-value for walls includes the cavity insulation and insulation sheathing, while the second R-value includes the mass wall when at least half the insulation is in the interior of the wall.
  • Floor insulation must maintain contact with the subfloor’s underside decking.
  • Basement insulation should be from the basement roof to the floor or at least 10 feet below grade.
  • All access from conditioned to unconditioned space must be weather stripped and insulated to equal the rest of the house standards.
  • Pipe and duct leakage must not exceed 4cfm per 100 square feet. Supply ducts in the attic must have an R-value of at least 8, other piping R-value 6, and boiler and hot water pipes R-value 3.
  • Air leakage from the building, including recessed lights, must not exceed 3 ACH.
  • Building documents and a permanent certificate of insulation must be provided showing all insulation and HVAC performance.

HERS Rating

HERS raters are industry-savvy experts at gauging the work of a professional insulation contractor. NAIMA helps raters with latest information and trends with which to determine if the insulation contractor has achieved a Grade 1 rating. The insulation contractors are not just keen for good ratings, but they also want to partner with homeowners in several areas. Honest ratings will inspire the contractor to seek lasting solutions for problems and to extend their warranties. The rater rates the performance loss in Effective Cavity Compression since compressed fiberglass has a higher R-value but the overall R-value is lower because the thickness reduces. The formula used by the rater is;

1. Batt Compression Ratio = (Batt thickness -cavity depth) / batt thickness X 100
2. Loss of R-value = ½ of rated R-value X Compression ratio
3. Effective R-value = Rated R-value – Lost R-value

For example, a batt of width 6.25” with an R-value 17, is installed in a cavity of size 2’x6’ and depth of 5.5”;

1. Batt compression ratio = ((6.25 – 5.5) / 6.25) X 100 = 0.75 / 6.25 X 100 = 12%
2. Loss of R-value = (0.5 X 17) X 12% = 1.02
3. Effective R-value = 17 – 1.02 = 15.98 or 16

If the performance loss remains within the recommended R-value, then the rater will retain the Grade 1 award but show the lower performance rating. Other defects in the work can downgrade the job to a Grade 2 or Grade 3. The rater can also be asked to make recommendations for air sealing or insulation packages.

Post-Insulation Inspection

Once an insulation job is completed, you should inspect it for the following;

1. Leaking Cavities

The insulation contractor must not use insulation to cover up dampness, and in fact must address the dampness first as a priority. If you have a problem of moisture leak after insulation work has been done and before the warranty period is over, then you should raise the issue with the contractor to remedy the shoddy work. The contract work should always include moisture control, which any professional insulator will address before carrying out the insulation work.

If the matter is not resolved, then you should check with the manufacturer if the material used was actually moisture resistant as claimed and that the material is still within the warranty period (most insulation materials have a long warranty period). The manufacturer will be obliged to carry out an independent check and determine if the cause of the problem is their material being defective, negligence on your part, or the contractor did not do the job correctly. You can then forward your complaint to the insulation affiliate for arbitration and recommendations.

2. Wall

The R-value of the material used should be clearly shown on the insulation, and it should meet the minimum requirements of the building code. Check that the batt or loose-fills leave no gaps at the top or bottom, but again that they fit snugly in the cavity. The electrical wiring should be properly covered with split or cut insulation. Batts should be cut to fit around and behind electrical boxes. Inset stapled faced batts should not be too compressed.

Pipes should be completely covered in insulation or firmly in contact with Kraft facing. Vapor retarders should be on the inner face of the walls of the living area. Kraft facing should never be exposed. Check the material and integrity of vapor retarder including Kraft facing, polyethylene sheeting, and some paints. The insulation around band joists should be non-flammable facing. Check the caulking or insulation are not overstuffed around the doors and windows. Bay windows, extended floor, ceiling, and outside wall should also be insulated.

3. Ceiling and Floor

The cantilevered floor should be insulated to the recommended floor R-value. The attic opening should be insulated with insulating covers or batt. Blown-in insulation for the attic should have a ruler for every 300 square foot and it should meet the minimum recommended depth. The attic card should be placed near the hatch during blown-in insulation installation. Baffles should be placed on eaves with vent. The knee wall should have the recommended R-value insulation and fire rating on the exterior.

4. Crawlspace

Inspect the “roof” of the crawlspace and the foundation walls for dampness and dangling insulating materials and lack of insulation in the pre-1990 houses. The crawlspace should have an R-value of between 11 and 19. All vents should be sealed and the floor should be vapor diffusion retarded. Check that measures have been taken to deal with rodents, pests, termites, bugs, and mold.

5. Other

Wet insulation is not usually a big problem with fiberglass, but saturated loose-fill insulation should be replaced. Gypsum board should be dry when installing. Unheated rooms adjacent to the living area need extra insulation on the wall, ceiling, and floor. Air sealing with rated air barrier is crucial for all types of insulation. The area between the tub or shower and the outside wall needs to be insulated. All insulation should be placed at least 3” away from a flame, chimney, heated flue pipes, and non-IS fixtures. Unfaced and special-faced insulation such as FSK-25 is acceptable as exposed surfaces.

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