Spray foam is very popular these days. But what is it? Spray foam is a very effective material for sealing, insulating and adding thermal value to your home. It’s made from two components that are mixed together and sprayed into place with a special gun. The first component is an open-cell spray foam insulation, which provides an air-sealing barrier. The second component is closed-cell spray foam, which adds strength and durability to the structure.
What Is Open-cell Spray Foam?
Open-cell spray foam is a versatile building material that can be used in a wide range of applications. It’s made by mixing water with air and expanding it into a foam. The resulting substance is very dense and highly insulating. Open-cell spray foam is often used as insulation in walls, roofs, attics and crawl spaces because it fills all the nooks and crannies of your home, providing a thermal barrier that prevents heat from escaping through cracks or other openings around windows, doors and other openings.
Open-cell spray foam typically has an R-value ranging from R-6 to R-7 per inch depending on how much is used in one application. This means that one inch of open-cell spray foam will keep 6 to 7 BTU of heat from escaping through the surface it covers — making it an effective insulator against cold air drafts coming through your walls or windows on winter nights.
Closed-cell spray foam consists of small bubbles that are closed on one side and open on the other side. This means that there is no passage of air through the material during curing; rather, it remains a solid piece until it has completely set up. Closed-cell foam cures at a slower rate than open-cell, but once completed, it creates an airtight seal between the outside of your home and its interior walls — making it ideal for sealing air leaks in attics or basements.
Closed-cell foam is made by mixing together water, borate and an organic blowing agent. Closed-cell spray foam has a much higher R-value than open cell because of its “closed” or solid cells that do not allow water vapor to pass through the material (which increases its insulating properties). Closed cell foam can be used in areas where there are no fire hazards but where there is a need for insulation such as attics or walls.
Closed-cell spray foam contains only one ingredient — polyol — which makes up about 80 percent of its composition. Due to this fact, closed-cell spray foam has no cell structure like open-cell does; instead, it’s rigid, solid foam that doesn’t compress when pressed down on or cut with a knife. Closed-cell spray foam comes in two main types: open-cell and low density.