Inspect the existing roof shingles or roofing membrane for any deficiencies.
Spray foam insulation on roof deck.
Where wood shingles or shakes.
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This construction approach was first used in the 1970s and it has been implemented much more widely since it was first included in the international code council s icc model building code in 2007 irc section 806 4.
If you ve never heard the phrase hot roof i m sure you ve heard of an unvented attic.
Damage investigations of spray foam insulation wood roof decks have found instances where deterioration of a wood deck has occurred due to water intrusion.
Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls.
This measure will convert a vented attic to a nonvented attic.
In the northwest where foam has been sprayed directly to the underside of roof decks for over a decade the building officials interpret the code to require removal of existing insulation.
The code allows for insulation directly to the underside of the structural roof sheathing providing the unvented attic is contained completely within the building thermal envelope.
Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly.
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.
The installation steps are as follows.
Spray foam insulation can create a barrier that reduces the drying rates of wood roof decks which may result in an unfavorable buildup of moisture in the wood.
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.
No interior class i vapor retarders e g plastic sheeting are installed on the ceiling side attic floor of the.
Insulate an attic in an existing home by installing spray foam open cell or closed cell on the underside of the roof deck.