This spray in foam insulation guide describes this product, its applications and its costs.
Spray in insulation is popular for its versatility and high insulating value. Open-cell and closed-cell options are available. Foam spray should not be confused with loose fill cellulose insulation which is often wetted and sprayed into wall cavities and attics. The fact that both are sprayed, though by different methods, is all they have in common in terms of the material. In addition, the type of spray foam we are discussing here is a product applied from a truck using a large tank and pressurized sprayer. We are not discussing the type of spray foam that comes in a small pressurized can and is used for spot insulation. The material is very similar, but the scale is very different.
About Spray In Foam Insulation
As the name implies, this product is a foam. There are two types commonly used. Polyisocyanurate or polyiso is a closed-cell foam that contains a low-conductivity gas in its cells that is free of hydrochlorofluorocarbons. The R-value is an outstanding R-5.5 to R-8 per inch of thickness, depending on the density of the foam. The initial R-value of polyiso may drop by R-1 or R-2 and then become stable. The drop is caused by some of the low-conductivity gas initially escaping before the product stabilizes.
The second type is polyurethane foam spray, another product with a gas inside that resists heat conductivity. Both open-celled and closed-cell products are available. The closed-cell type expands and has a higher R-value of R-6.5 per inch of thickness. Open-celled polyurethane foam has an R-value of R-3.5 to R-5.5 depending on the density of the foam. Some of the gas may escape in the first year or two after these products are installed. This is known as “thermal drift” and will slightly reduce the R-value of the product.
There are a couple of reasons to consider spray in foam insulation. The first is that it offers excellent insulation qualities, especially closed-cell products. You get a higher R-value per inch of thickness than with most other insulation types.
Secondly, because the product is sprayed on as a liquid that cures into a foam, it does a very good job of filling gaps and stopping the flow of air. There are no seams either, as you will have with insulation batts or rigid foam boards.
Both types of foam insulation are applied with a large sprayer, so a large area can be covered in insulation in a relatively short period of time.
All types of spray foam insulation form a moisture barrier, so applying one over the foam is not necessary.
Because of its versatility, this product can be used just about anywhere. Most commonly, it is used on basement foundations, in wall cavities and in hard-to-reach locations. It is an excellent choice for insulating the space where the framing of the home rests on the foundation. Spray foam insulation is also used in attics, though caution needs to be used so that it is not installed in such a way that traps moisture in space where it can cause mold or rot.
The material itself can be more expensive than some other types. The upside is that you receive a product with very high R-value and one that seals drafty areas like attics better than other types of insulation.
Table 1: Prices shown for Spray Foam Insulation, divided down into Material per Sq. Foot and Labor per Sq. Foot:
|Insulation Rating||Material per Sq. Foot||Labor per Sq. Foot|
|R-13||$0.90 to $1.60||$0.57 to $0.90|
|R-19||$1.30 to $2.50||$0.75 to $1.00|
|R-21||$1.40 to $2.70||$0.75 to $1.10|
Additional supplies and materials will come to $40-$60 per 1,000 feet of space covered by the insulation. This is consistent with other types of insulation.
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