Typically water based and very light density, this foam has the consistency of angel food cake. It weighs about .5 pounds per cubic foot. Air bubbles inside foam burst open, hence it is called ‘open cell’. Some types of open and closed cell foam have a soy base, although this soy base is still typically accompanied by strong chemicals.
- Excellent air seal.
- Typically half the cost of closed cell foam, which is part of its popularity.
- Lower expansion pressures when curing, some types can be used in existing walls without breaking drywall.
- Poor R-value only equal to cellulose for 2-3 times the cost of cellulose.
- Tends to absorb moisture.
- Chemicals used while installing it are pretty nasty and often state that no humans should go inside the building for 2-7 days after installation.
- Not particularly “green”.
- Does not prevent radiant heat transfer – the primary source of heat-flow in and out of buildings.