SPF (spray foam) is receiving greater recognition because of its ability to make homes more efficient. Like Cellulose, SPF is injected into the building cavities one bay at a time. SPF is a very effective air-barrier and is available in many different chemical make ups and R-values per inch. SPF also adds to the strength of the building by adhering to the many building surfaces and using it own rigidity. Widely known Icynene is a low density foam at R-3.6.
Several low density foams are offered in eco friendly formulas; soy-based, bio-polyols or even mushroom base. Many Icynene or polyurethane SPF’s are on the market; many have VOC’s (volatile organic compouind), CFS’s (chlorofluorocarbons) or HCFC’s (Hydrochlorofluorocarbons) within their chemical makeup; none is toxic, yet all are ozone depleting.
One of the highest insulation R-values achieved per inch is polyisocyanurate SPF (at R-7.6 its hard not to consider); yet the cost can be substantial. Spray foam offers many uses and options. Choosing the right product, its application, and the proper installer, are key components to a successful SPF investment.
Insulation R-Values Per Inch
|Fiberglass batts or blown
Icynene (low density spray foam)
Expanded Polystyrene (white)
Extruded Polystyrene (blue/pink)
Polyurethane (spray foam or board)
Polyisocyanurate (spray foam or board)
|2.4 – 3.0
3.3 – 4.0
3.6 – 4.2
5.8 – 6.8
5.6 – 7.6