Do You Need Attic Ventilation With Spray Foam Insulation

Earlier this year i got a question about a home that had spray foam insulation in the attic.

Do you need attic ventilation with spray foam insulation.

Becoming more affordable significant long term energy savings sealing restricts air movement through the building envelope. This alternative to traditional building insulation fiberglass can be applied into wall cavities holes concrete slabs and even onto roof tiles and. Oh and when you put it in your attic spray foam. Many homeowners love spray foam insulation and it s easy to understand why.

A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits but then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents. All insulation materials require proper venting. 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. The most important thing to remember is to use the correct type of insulation and to ensure it is installed correctly.

Nothing unusual about that. Unvented attic assemblies unvented attics rely on an air impermeable insulation installed to the roof deck s underside i e. Heat from the house rises up to the attic but when there isn t one the heat rises up to the roof. One huge benefit of the spray foam insulated attic is that conditioned air leakage from the ac furnace duct system is contained and used to condition the attic.

Cathedral roofs especially need a lot more insulation between the ceiling and the rafters because there usually isn t any attic space. Rigid foam and spray foam are two of them. Now we use attic ventilation when we use products like fiberglass because we have to manage the moisture. However in a traditionally insulated attic insulation on the ceiling the attic is vented.

Ventilation and moisture control in spray foam homes spray foam insulation has been increasing in popularity over the last several years due to. That is now a conditioned part of your house just like any room in your house. When we seal the attic with spray foam it s as tight as a butter tub. But with spray foam ventilation is not an issue.

Spray polyurethane foam is a chemical product that is created by two materials isocyanate and polyol resin that will react with each other when they are mixed and will expand up to 30 to 60 times its liquid volume as it is sprayed in place.