Spray Foam Attic Roof Deck

If the intent of installing spf to the roof deck was to create a conditioned attic non vented then the recommendation would be to first remove any insulation and vapor retarder from the attic floor then to install spf on the roof deck and gable walls.

Spray foam attic roof deck.

But a common reason to put spray foam on the roofline is to avoid having to air seal the attic floor. If you leave the insulation in the attic floor after insulating the roofline the attic will be cooler in winter than if you remove the insulation. And vented or unvented attics that are insulated above the roof deck with rigid foam. 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.

It is important to note that icynene is a brand name similar to how a tissue is referred to as kleenex. Thus the air in the attic is connected with the air in the house. The most common spray foam product used to insulate attic roof decks is open cell spray foam insulation sometimes referred to as half pound foam or icynene seen in the images on this page. Unvented attic assemblies unvented attics rely on an air impermeable insulation installed to the roof deck s underside i e.

The insulation reduces wildly high temperature spikes and so the attic becomes a conditioned part of the home like any other room. Most people do not realize the requirements for proper venting of an attic. In a normal household where the occupants take a few showers and do some cooking some of the water vapor may well find its way into the attic. Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly.

High efficiency attic insulation helps provide added thermal protection lessens wasted energy and increases enhanced comfort and quiet. If you do not have proper ventilation you are in essence cooking your shingles. Unvented attics that are insulated on the underside of the roof deck with blown spray foam. 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.

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. An attic that is properly vented has 50 intake of fresh air and 50 exhaust of the hot air. 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.