You might be asking yourself What Type of Spray Foam Insulation Should I Use ?
There are two main types of spray foam insulation: closed cell and open cell. The type you use will depend on several factors. Closed cell insulation is more rigid than open cell insulation. In addition, the R-value is higher than open cell (R-value is a measure of resistance to heat). Because of its density and rigidity, closed ell expands more slowly than open cell. It has a smaller cell structure and is more compact, which makes it an excellent air or water barrier.
Open cell expands and cures quickly, which gives it a softer, spongier density. In open cell insulation, the cells do not completely close. It uses less chemicals than closed the closed cell type, which usually makes it less expensive. While it is an effective air barrier and provides sound reduction, it is not an effective water barrier because of its lower density.
So when do you use open cell versus closed cell? The biggest consideration is “location, location, location.” For new construction, ceilings and interior walls are often insulated using open cell insulation due to its effective soundproofing. It is also effective to use a slow-curing open cell type when you are retrofitting wall insulation because other types may cause your walls to bulge.
For attics, roofs, or tank insulation, closed cell insulation is the better choice. Its greater density provides a much better water barrier. It also does a better job of keeping a home or building warm in winter and cooler in summer. It also has a greater resistance to air and gas leakages.
While the greatest location consideration when choosing a type of insulation may be the indoor location, the location of the home itself is also important. For example, closed cell foam can be found in three-pound (1.36 kg) spray and two-pound (0.9 kg) spray. Three pound spray is the densest, so it provides the highest R-value. However, if you live in a wet or humid climate, three pound foam can result in trapped moisture, which can cause the roof to rot. Half-pound (0.23 kg) foam is the best value, which makes it very popular. It is about the same density as dormant air. However, it has a lower R-value, so it is not approved for vapor and fume control, so in general, regardless of climate, this type of foam is best kept to interiors and walls.
For an easy to remember “when to use” guide, consider these thoughts:
Open cell foam can be treated similarly to cellulose or fiberglass foam, with the additional benefits of better coverage and fit, which results in a better air barrier and better soundproofing. Closed cell foam, however, provides the best water vapor barrier and has the highest R-value. In general, the interior of your home is the best place for open cell, while closed cell is a better choice for exterior walls and roofs. In all cases, spray foam provides a better seal, fit, and greater protection than traditional foam because it can go where roll-out or blown foam cannot, and it can expand to fill gas more effectively.