Do Attics Require Ventilation With Spray Foam Insulation

Do attics with spray foam insulation need ventilation.

Do attics require ventilation with spray foam insulation.

Nope you absolutely do not need to ventilate a spray foam house and here s why. Attic ceiling to stop airborne moisture from reaching a cold surface and condensing inside the building envelope in this design insulation effectively separates the interior and exterior spaces while slowing down moisture flow so the dewpoint is not achieved within. However in a traditionally insulated attic insulation on the ceiling the attic is vented. Unvented attic assemblies unvented attics rely on an air impermeable insulation installed to the roof deck s underside i e.

Here s the answer to the question posed in my article title. Because basically now that attic is a conditioned space. The ventilation helps to keep the air fresh in the home the insulation stops warm air from escaping and cold air from leaking in. This spray foam is applied as a low or high pressure two component polyurethane spray foam that can be applied onto walls in unvented attics to ducts and ceilings and in vented attics and crawl spaces.

When we seal the attic with spray foam it s as tight as a butter tub. It is also known to act as an air barrier however unfortunately it will not protect against vapor and moisture intrusions. It s terrific because it s pretty much the same temperature as the rest of the house all the time. Oh and when you put it in your attic spray foam insulates the attic itself.

Compared to traditional insulation whether fiberglass or cellulose spray foam has the potential to provide better performance via its air sealing properties high r values per inch of thickness and in the case of closed cell spray foam ability to repel moisture.