Closed-Cell Spray Polyurethane Foam (SPF) is a much more dense, hard and rigid foam with an R-value of 6.8 per inch. It is often used in attics with metal roofs, attic floors, exterior walls, crawl space sub-floors and metal sheds. As with all foams, the airtight barrier that is created is what prevents dust, pollen, mold and mildew from penetrating the envelope. The tiny cells in this type of foam are literally “closed off” making it impervious to air and water.
Once applied this foam expands to 20 times it’s liquid volume. Its performance is superior to commonly used fiberglass insulation because of it’s ability to adhere to nearly any building material and it’s ability to provide a continuos barrier against air and moisture infiltration.
The results of using closed-cell SPF are a cleaner environment, greater noise reduction, and substantial energy savings. Additionally, Closed-cell foam has been shown to increase building strength and wind resistance up to 300%.
Open-Cell Spray Polyurethane Foam (SPF) is an extremely lightweight soft foam with an R-value of 3.8 per inch. It is often used in attic roof-lines, exterior walls and basement ceilings. It can also be used as a sound barrier for theater rooms, bathroom and plumbing pipes.
In attics, open cell is highly recommended for it’s performance due to the thickness, air sealing and insulating properties of the foam. At an average of 5.5 inches (R-value of 21), open cell foam applied to the underside of the roof decking will eliminate radiant heat from affecting the indoor temperature and HVAC unit performance. Basically, it keeps conditioned air inside the home/business while preventing un-conditioned air from entering the structure.
On average your attic temperature should not see more than a 10-13 degree difference from the living space below it.