Under Roof Insulation Spray Foam

Unvented roofs with spray foam applied to the underside of the roof deck have been used since the mid 1990s.

Under roof insulation spray foam.

As the name suggests spray foam insulation is a liquid foam which is sprayed into position and sets into an insulating layer. Technically known as spray polyurethane foam or spf spray foam is most commonly applied in the space between attic rafters. Open cell and closed cell. 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.

Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. It s not coming from above the roof and it s not some new moisture source resulting from the spray foam. 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. 2 many say it has a british board of agrement or bba approval which means the same thing.

Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly. It can act as an air and moisture barrier in addition to providing very high r value. It will help you to eliminate problems that may come when the house becomes extremely cold in the winter and terribly hot in the summer. Open cell spray polyurethane foam ocspf and closed cell spray polyurethane foam ccspf insulation sprayed to the underside of roof sheathing is a popular strategy for increasing roof insulation levels in all climate zones.

According to the us environmental protection agency epa spray foam is recognized as a premier alternative to the batt insulation of years past. The spray on foam is a rigid foam that is lightweight normally sprayed on to the underside of the roof approximately 50 to 100 mm thickness. Better materials for attic roof insulation are rigid foam boards and spray foam insulation. It has been in use for over 30 years and is now becoming increasingly popular as it s an effective insulator and can also stop air leakage.

1 some manufacturers advise that the spray foam is breathable some of them say nothing at all about this. Open cell spray polyurethane foam or closed cell spray polyurethane foam ccspf insulation can be sprayed along the underside of the roof sheathing to provide a conditioned and insulated attic space that can be durable and efficient in all climate zones see figure 1. Lstiburek takes blame for bad language. Serving as both an air sealant and an insulator spray foam is estimated to reduce the standard hvac sizing by about 35 on average.

There are two types of spray foam.