What is spray foam insulation?
Spray foam insulation is created by using special equipment to mix two chemical ingredients together. The resulting mixture is applied with a spray gun to a building structure, such as the interior surface of drywall or the underside of plywood roof sheathing. The liquid spray mixture expands from 30 to 100 times its original volume—depending upon the specific foam product—and hardens into a solid plastic barrier within less than 10 seconds. Spray foam bonds chemically to the surface it is applied to. With closed-cell spray foam, this bonding action adds strength to a wall or roof structure.
Spray foam’s behavior of expanding when applied allows the foam to fill even the smallest cracks and openings, sealing walls and roof structures against air infiltration. This ability to block almost all air infiltration gives spray foam insulation a big part of its dramatic insulating performance advantage over fiberglass and other fiber insulations.
Is spray foam insulation a new technology?
No. Spray foam insulation appeared during the 1960s. The first applications were for commercial cold storage facilities and industrial projects. Insulation contractors later applied spray foam to roofing systems. An interesting historical note: Energy costs were not really a concern during the 1960s. Spray foam insulation was actually first tested in roof structures because of its water resistance.
If spray foam insulation is so much better than fiberglass and cellulose, why isn’t everyone using it?
This is a fair question. There are three reasons. First, the earliest spray foam insulation products contained large amounts of formaldehyde. As safety concerns about toxic building materials emerged during the 1970s, spray foam insulation fell out of favor. Today’s spray foam insulation products do not contain formaldehyde.
Second, fiber insulation products are less expensive than spray foam insulation. This gave a decided advantage to fiberglass insulation products during the era of cheap energy. Today, with spiraling energy costs, spray foam insulation is a much better long-term value than fiberglass or cellulose insulation.
Third, we now know from modern building science research that about 40 percent of indoor air conditioning and heating costs are attributable to air infiltration through walls, ceilings and attic spaces. Fiber insulations are completely porous and don’t do a very good job of blocking heat transfer related to air infiltration. Spray foam insulation, on the other hand, virtually eliminates air infiltration through insulated structures.
Is spray foam insulation code-approved?
Yes. Building codes provide for the use of spray foam insulation in the Foam Plastic section. This section of the code also describes requirements for thermal barriers.
Is it true that no contractor’s license is required to install insulation?
Unfortunately, this is true. And it’s too bad because incorrectly installed insulation can rob you of valuable energy savings and, in the case of fiberglass and cellulose, create conditions for mold, mildew and unhealthy air quality. We’ve installed more spray foam insulation than most other insulation companies in Austin.
What if we want to add or move an electrical outlet after spray foam insulation is installed?
Your electrical contractor can pull wire through the insulation. If you have a situation where wiring may require periodic access, such as a home theater room, we recommend that you place ENT conduit within the wall structure before the spray foam insulation is applied.
I’ve seen pictures that show big uneven bumps of spray foam insulation bulging out of an unfinished frame wall during renovation or new home construction. Does this create a problem when installing the drywall sheathing?
No. After the foam has set and hardened, the technician uses either a straight edge scraping tool or a hand saw that is wider than the space between the framing studs to remove any spray foam insulation that has expanded out past the width of the frame wall. The finished foam insulation surface is smooth and level with the faces of the exposed framing studs.