Unvented Attic Spray Foam Insulation

The insulation extends down the roofline to the rim joists and soffit areas as well as on gable wall ends.

Unvented attic spray foam insulation.

Humid or cold climates require either rigid foam insulation above the roof deck to keep its temperature above 45 f. Air impermeable insulation typically spray foam installed to the underside of the roof sheathing. This allows you to install your bulkheads above the ceiling plane without the need for spray foam insulation. Spray foam in unvented attics intended for regular use helps.

Insulation approaches for unvented attics vary by climate. Common problems found with traditional insulation in an unvented attic assembly can be mitigated with spray foam insulation like icynene. Insulating unvented attics with spray foam figure 1 spray foam is a good choice for roofs that are difficult to vent like a turret with converging rafters left or a flat roof with its rafters hung between flush beams right. If you want you can even transform a spray foamed attic into a finished space.

This is done by using what is referred to as air impermeable insulation such as rigid foam board or spray foam. When you insulate the top of your attic with spray foam you re bringing your attic into your home s envelope. Over time feedback from builders and building owners has been and continues to be overwhelmingly positive especially in the areas of moisture performance energy efficiency and building durability. An alternate to spray foam insulation in an unvented attic is plenum trusses which allow you create a reverse bulkhead above the ceiling plane that is insulated.

Two acceptable methods for insulating an unvented attic assembly in all climates are as follows. The unvented attic space is considered the most effective and up to date building practice particularly by the spray foam industry. Using spray foam insulation in an unvented attic application both low density open cell and medium density closed cell spray foam can be used in an unvented attic to provide the needed thermal resistance and airtightness. Fibrous insulation e g batt or blown in can be installed under the roof deck in the hot dry climate zone but this will cause moisture problems in all other climates straube and grin 2010.

Unvented attics sometimes called sealed enclosed or encapsulated attics feature insulation on the underside of the roof decking rather than on the attic floor.