Spray Foam

Polyurethane spray foam falls into two categories: "open-cell" or "closed-cell". There are pros and cons of both and AHE can determine which spray foam type would be best depending on the application. Spray foam tends to be more expensive than other spray insulation products, but it has an advantage of being a rated vapor barrier and is commonly the best solution for vaulted ceilings and areas where a high R-value is needed. Spray foam is composed almost entirely from petroleum so we do not consider it a “green material”. Bio-based spray foam insulation has been introduced as a “green” spray foam but the actual bio-content is typically less than 10% with the remaining 90% petroleum. However, foam manufacturers claim that the embodied energy and petroleum it takes to produce is quickly made-up in energy savings when used in the home. Bottom line: we feel that spray foam is a good choice for certain applications and offer it as one of our insulation options.

Open-cell spray foam
Open-cell spray foam is less dense than closed-cell and can expand 120% in 3 seconds. This allows the spray foam to cover a larger area and makes it a more economical solution than closed-cell. The R-value is typically R-3.8 per inch which gives a 2x4 wall R-15. Open-cell foam insulation can be over-sprayed in a wall and then scrubbed to create a completely uniform insulation barrier. In addition to its thermal insulating R-value, spray foam acts as an excellent air barrier. This is very important in homes that are leaky which benefit from the reduced air infiltration provided by spray foam. Open cell foam is also very effective as a sound barrier, in walls it can provide an excellent STC rating of 52.

Closed-cell spray foam
Closed-cell spray foam is very dense which gives it a high R-value of R-6.8 per inch. The obvious advantage is that it can be sprayed in shallow cavities and still provide an overall high R-value. A 2x4 vaulted ceiling sprayed with 3.5” of closed-cell spray foam will yield an overall R-value of R-24. The density of closed-cell foam makes it a very effective air and moisture barrier, however on the flip side it does not make a good sound barrier. Finally, closed-cell foam has shown to increase the rigidity and strength of wall assemblies which adds structural support to the building.

Side by side comparison of Spray Foam Features