Insulating and providing airtightness with spray foam at the underside of the roof as part of an unvented attic assembly will elevate such concerns.
Spray foam underside of roof in attic.
Unvented attics rely on an air impermeable insulation installed to the roof deck s underside i e.
In this design insulation effectively separates the interior and exterior spaces while slowing down moisture flow so the dewpoint is not achieved within the building envelope.
Moisture generated indoors or that infiltrates into the home is responsible for the bulk of the moisture in an attic insulated with spray foam on the underside of the roof sheathing.
Polyurethane or polystyrene spray foams can provide thorough coverage to roof rafters and attic walls in much less time than is needed for other materials.
Spray foam insulation in an unvented attic assembly has been one of the most researched and widely implemented innovations of recent years.
The insulation reduces wildly high temperature spikes and so the attic becomes a conditioned part of the home like any other room.
Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls.
When spray foam is installed on the underside of the roof deck the attic space is insulated from heat that otherwise would be entering the attic.
It s not coming from above the roof and it s not some new moisture source resulting from the spray foam.
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