Spray Foam Insulation Attic Ventilation

What you re looking at there is the place where a power attic ventilator had been.

Spray foam insulation attic ventilation.

If a blower door test reveals that your spray foam insulation reduced ventilation beyond an acceptable level you may need to install one of these units in your home. High attic humidity often results from spray foam insulation. Becoming more affordable significant long term energy savings sealing restricts air movement through the building envelope. Earlier this year i got a question about a home that had spray foam insulation in the attic.

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. Ventilation and moisture control in spray foam homes spray foam insulation has been increasing in popularity over the last several years due to. Unvented attic assemblies unvented attics rely on an air impermeable insulation installed to the roof deck s underside i e. This alternative to traditional building insulation fiberglass can be applied into wall cavities holes concrete slabs and even onto roof tiles and.

Attic ventilation and spray foam don t mix that photo above is from an existing home that had spray foam insulation installed in the attic over the master bedroom. Nothing unusual about that. Sometimes humidity levels spike in an attic after a spray foam job. 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.

Unvented attics sometimes called sealed enclosed or encapsulated attics feature insulation on the underside of the roof decking rather than on the attic floor. Both low density open cell and medium density closed cell spray foam can be used in an unvented attic to provide the needed thermal resistance and airtightness. 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. The unvented attic space is considered the most effective and up to date building practice particularly by the spray foam industry.