Spray Foam Underside Of Roof

Spraying foam on the underside of your roof is a great way to stop air from flowing out of the top of your house.

Spray foam underside of roof.

I m constructing a new home along the rhode island shore. When the choice is made to insulate along the underside of the roof deck spray foams have advantages over other insulation types because of the ability of spray foams to effectively air seal complex assemblies. It s not coming from above the roof and it s not some new moisture source resulting from the spray foam. This is important because you do not want water vapor within the foam condensing at the juncture where it contacts the metal.

Closed cell foam also contributes additional rigidity to the roof while remembering our minimum safety assumption. Lstiburek takes blame for bad language. Installing the baffles will provide a better installation than spraying directly against the underside of the roof sheathing. Thanks for filling in the missing details.

My answer is unchanged. When it comes to spray foam insulation that is applied to the underside of the roof between the rafters the financial benefits are even more impressive with the initial outlay recouped within just a few years on average. As i m sure you know 8 inches of closed cell spray foam is neither cheap nor particularly green but in your circumstances the spray foam may make sense. 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 attic is unvented for instance no ridge vent exists. You can spray foam anywhere you d like to separate the inside from the outside. Watch this video on youtube. 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.

Yes you can spray foam the underside of your roof. No airsealing hence i want to remove the fiberbatts and spray 3 inches of closed cell spray foam in before putting the fiberbatts back in place. Should i put any membrane or the like on the underside of the roof sheathing before spraying the foam in. The attic will be a conditioned space and i m planning to apply spray foam insulation to the underside of the roof sheathing.

The spray foam can also serve as the thermal and vapor control layers in both new and retrofit construction. Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. The roofing materials are installed and consist of timberline shingles and full coverage ice and water barrier the entire roof.