Spray Foam Attic Roof

Using spray foam insulation in an attic is a popular energy saving project.

Spray foam attic roof.

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

You ll also see another safety hazard and code violation. Most people do not realize the requirements for proper venting of an attic. The main concern with spray foam insulation and shingle warranty is proper attic ventilation. Consumers are often told by spray foam contractors to do the rafters.

Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. If you re using the attic for living space then you need to insulate the rafters. 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. 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.

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. It s important you spray foam attic rafters only if you need to. Lstiburek takes blame for bad language. An attic that is properly vented has 50 intake of fresh air and 50 exhaust of the hot air.

And the benefits range from much lower utility bills to fewer pests to reduced sound transfer. It will also help keep any duct leaks within the conditioned space of your attic. When we seal the attic with spray foam it s as tight as a butter tub. The attic you see in the photo here is a different home but it does have one feature in common besides the spray foam.

The installer sprayed foam directly on the metal flues. 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. 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. You should never do this.

In a vented attic all of that expensive airflow is lost to the environment. Using icynene spray foam as your attic insulation will turn your attic into a conditioned space. Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly. Sealing the top of the house keeps the air you paid to heat and cool inside your home.