Spray Foam Attic Roof

If you look closely you ll see two exhaust flues on the left side.

Spray foam attic roof.

Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. You should never do this. 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. In a vented attic all of that expensive airflow is lost to the environment.

It s important you spray foam attic rafters only if you need to. The attic you see in the photo here is a different home but it does have one feature in common besides the spray foam. One huge benefit of the spray foam insulated attic is that conditioned air leakage from the ac furnace duct system is contained and used to condition the attic. You ll also see another safety hazard and code violation.

It s quick and easy to do. It s not coming from above the roof and it s not some new moisture source resulting from the spray foam. Using icynene spray foam as your attic insulation will turn your attic into a conditioned space. It will also help keep any duct leaks within the conditioned space of your attic.

Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly. The main concern with spray foam insulation and shingle warranty is proper attic ventilation. Sealing the top of the house keeps the air you paid to heat and cool inside your home. The insulation reduces wildly high temperature spikes and so the attic becomes a conditioned part of the home like any other room.

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. Most people do not realize the requirements for proper venting of an attic. When we seal the attic with spray foam it s as tight as a butter tub. The installer sprayed foam directly on the metal flues.

An attic that is properly vented has 50 intake of fresh air and 50 exhaust of the hot air. If you do not have proper ventilation you are in essence cooking your shingles. Consumers are often told by spray foam contractors to do the rafters. Using spray foam insulation in an attic is a popular energy saving project.

If you re using the attic for living space then you need to insulate the rafters. This will allow for optimal operation of your hvac equipment as well as aid in early detection of situations such as roof leaks and wind driven moisture intrusion. If you re not do the attic floor. Lstiburek takes blame for bad language.