Open Cell Vs Closed Cell Foam Under Roof

I started all this spf stuff under roof decks in the early 1980s.

Open cell vs closed cell foam under roof.

Closed cell or high density foam is a better insulator and will not take on water. When it comes to insulating a home whether that s a roof insulation or floor insulation it is ideal to use icynene open cell spray foam. Closed cell foams use enovate also known as 245fa which is. Open cell foams most commonly range from 5 lb to 7lb densities.

However open cell and closed cell have their different uses. The open cell material is more affordable compared to closed cell and expands more which makes it an excellent material for tight spaces and areas with nooks and crannies. Spray foam is categorized into two types open cell or closed cell. Closed celled foams will perform better in terms of deflecting water away from interior elements but may allow leaks to go undetected longer.

Open cell is lightweight foam that is flexible and an excellent air barrier. Closed cell foam has a higher r value than open cell foam usually about 6 0 per inch. Most open cell foam has a density of about 5 pounds per cubic foot. As with all construction products installation is critical to the performance of the product.

It is often used for roofing on commercial buildings. Chemical manufacturer s claim if a roof leaks water will migrate through the foam structure therefore not trapping the water. Common sense tell s me if this is valid marketing then what stops water vapor from moving through the foam under pressure. Open cell foams use water as a blowing agent.

I m afraid i must digress from hoebeke builders opinion open cell foam will take on and hold water it is open. Closed cell foam can be over three times that with a density of 1 75 pounds per cubic foot or more. Benefits of open cell spray foam. A foams r value is its resistance to heat flow or in other words how well they insulate.

Closed cell foam is much denser than open cell foam. Stop with the stupid comments about open cell being better under a roof deck than closed cell because if there is a leak the leak either dries faster or you can see it sooner. Both icynene open cell and closed cell spray insulation are effective insulators with both working as barriers for air leakage. Let s not confuse open cell vs closed cell foam.

Open cell foam is just that open cell. Open and closed cell foam insulation use a blowing agent to forms the cells within it. There is no compelling evidence one way or the other.