It used to be that the “insulation” of the building conjured up images of rolls of fiberglass batting material in pink or white/yellowish color. Since the late 1930s, long strips of fiberglass batting have been cut to fit between wall studs and sandwiched between the exterior and interior wall of sheetrock.

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 by the inhalation of small fiberglass particles that can be dislodged from the batting during handling. Protective mask, gloves, goggles, and clothing were standard safety equipment when installing fiberglass insulation.

And despite its insulating effectiveness, fiberglass doesn’t provide a really good air and vapor barrier if it’s not installed correctly.

Many of today’s commercial construction projects are insulated with foam products that provide 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 a polyurethane product developed in 1937 by German industrial chemist Otto Bayer. It was brought to the United States where it was used in aviation and military projects in the mid-1940s.

After the war, the automotive industry began using polyurethane polymers in car bodies, and the housing industry began using it on a limited basis to insulate houses. 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 are more energy efficient and are achieving better and better “green ratings.” This insulation is used in many residential 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.” In general, the higher the R value, the greater the resistance to heat flow. Spray foam insulation has higher R-value ratings than fiberglass insulation.

Modern spray insulation used in construction is typically one of two types: “open cell” or “closed cell” foam.

• Open cell foam is made up of small foam cells that are not completely closed. Air fills the “open” space within 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 of closed cell foam).

• Closed cell foam is made up of fully closed cells that are densely packed and filled with gas, which allows 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, due to its higher cell density, provides structural reinforcement to insulated surfaces.

Benefits of spray insulation

This insulation offers a number of unique advantages when used in commercial and residential construction:

• This insulation has no food value, which means that the foam is of no food interest to destructive insects and rodents.

• Bacteria and fungi cannot grow in 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 “continuous thermal wrap” that effectively seals leaks and voids and keeps out insects and vermin.

• Spray foam insulation sticks to any clean, dry surface—it won’t 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 climate insulation benefits for almost any construction application imaginable.

Your initial expense will be more than offset by its durability (over 80 years), its ability to fill even the smallest areas that fiberglass can’t even reach, and provide greater energy efficiency, thereby lowering energy expenses.

With the increasing focus on energy efficiency, it is very likely that spray foam insulation will continue to gain use in both the residential and commercial construction industry.