Spray Foam Attic Roof

Most people do not realize the requirements for proper venting of an attic.

Spray foam attic roof.

Sealing the top of the house keeps the air you paid to heat and cool inside your home. It will also help keep any duct leaks within the conditioned space of your attic. Lstiburek takes blame for bad language. 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.

Using spray foam insulation in an attic is a popular energy saving project. In a vented attic all of that expensive airflow is lost to the environment. 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. It s not coming from above the roof and it s not some new moisture source resulting from the spray 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. You ll also see another safety hazard and code violation. You should never do this. 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.

Consumers are often told by spray foam contractors to do the rafters. The insulation reduces wildly high temperature spikes and so the attic becomes a conditioned part of the home like any other room. It s quick and easy to do. If you re using the attic for living space then you need to insulate the rafters.

Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. Using icynene spray foam as your attic insulation will turn your attic into a conditioned space. It s important you spray foam attic rafters only if you need to. The installer sprayed foam directly on the metal flues.

And the benefits range from much lower utility bills to fewer pests to reduced sound transfer. If you re not do the attic floor. The attic you see in the photo here is a different home but it does have one feature in common besides the spray foam. 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.

If you look closely you ll see two exhaust flues on the left side. If you do not have proper ventilation you are in essence cooking your shingles. When we seal the attic with spray foam it s as tight as a butter tub. An attic that is properly vented has 50 intake of fresh air and 50 exhaust of the hot air.