It used to be that building “insulating” evoked images of rolls of fiberglass batting material in either pink or white / yellowish color. Since the late 1930s, long strips of fiberglass batting have been cut to fit between walls studs and sandwiched between the exterior wall and the sheetrock interior.
Fiberglass provided far superior (and safer) building insulation than had been used in construction for centuries. But it was, and is not without a significant health risk caused from inhaling the small fiberglass particles that can break free from the batting during handling. Protective mask, gloves, goggles, and clothing were standard safety equipment when installing fiberglass insulation.
And since its insulating effectiveness, fiberglass does not provide a truly good vapor and air barrier if not properly installed.
Many of today's commercial construction projects are being insulated with foam products that are providing greater insulation and other intrusion resistance than fiberglass batting. Let's explore some of the history and uses of foam insulation.
The short story
Spray foam insulation is polyurethane product that was developed in 1937 by the German industrial chemist, Otto Bayer. It was brought to the United States where it was used in military and aviation projects in the mid-1940s.
After the war, the auto industry began using polyurethane polymers in car bodies and the housing industry began using it on a limited basis for insulating homes. By the 1970s, technology had improved the application and affordability of spray insulation for use in the construction industry.
Today's spray foam insulation products provide greater energy efficiency and are achieving increasingly improved “green ratings.” This insulation is utilized in many housing and commercial construction projects around the world.
R-value ratings, Open Cell and Closed Cell foam insulation
Insulation has an R-value rating, “a measure of resistance to heat flow through a given thickness.” Generally, the higher the R-value, the greater the heat flow resistance will be.Spray foam insulation has higher R-value ratings than does fiberglass insulation.
Modern spray insulation used in construction is usually one of two types: “Open Cell” or “Closed Cell” foam.
- Open Cell foam is comprised of tiny foam cells that are not fully closed. Air fills the “open” space inside the material. Open Cell foam has an R-value of 3.4 to 4.5 per inch.
Open Cell insulation is a very effective sound barrier (nearly twice the sound resistance as Closed Cell foam).
- Closed Cell foam is comprised of fully closed cells densely packed together and filled with gas, enabling the foam to rise and expand. Closed Cell foam has an R-value of 5.4 to 7.2 per inch.
Closed Cell provides superior insulation and because of its greater cellular density it provides structural reinforcement to insulated surfaces.
Benefits of spray insulation
This insulation offers a number of unique benefits when used in commercial and residential construction:
- This insulation has no food value meaning that the foam is of no food interest to destructive insects and rodents.
- Bacteria and fungal growth can not develop on spray foam insulation because it is an inert substance.
- Applied in liquid form, spray foam insulation expands and conforms to all open spaces creating a “continued thermal envelope” that effectively seals off leaks and gaps and results insects and vermin from entering.
- Spray foam insulation adheres to any clean and dry surface, will not shrink, settle, or disintegrate.
Value in commercial construction
Spray foam insulation is more expensive to install than traditional fiberglass insulation. However, spray foam offers considerable sound and weather insulation benefits to nearly any imaginable construction application.
Its initial expense will be offset by its durability (80+ years), its ability to fill even the smallest areas that fiberglass can not even reach, and provide higher energy efficiency thus reducing energy expenses.
With the increasing focus on energy efficiency, it is highly likely that spray foam insulation will continue to gain in use in both the housing and commercial construction industries.