Unvented Attic Spray Foam Insulation

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.

Unvented attic spray foam insulation.

The unvented attic space is considered the most effective and up to date building practice particularly by the spray foam industry. Common problems found with traditional insulation in an unvented attic assembly can be mitigated with spray foam insulation like icynene. 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. This is done by using what is referred to as air impermeable insulation such as rigid foam board or spray foam.

Humid or cold climates require either rigid foam insulation above the roof deck to keep its temperature above 45 f. Spray foam in unvented attics intended for regular use helps. 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. Insulation approaches for unvented attics vary by climate.

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. If you want you can even transform a spray foamed attic into a finished space. The insulation extends down the roofline to the rim joists and soffit areas as well as on gable wall ends. Two acceptable methods for insulating an unvented attic assembly in all climates are as follows.

When you insulate the top of your attic with spray foam you re bringing your attic into your home s envelope. Unvented attics sometimes called sealed enclosed or encapsulated attics feature insulation on the underside of the roof decking rather than on the attic floor. Spray foam insulation in an unvented attic assembly has been one of the most researched and widely implemented innovations of recent years. Air impermeable insulation typically spray foam installed to the underside of the roof sheathing.

As a result you can reduce the temperature in your attic by a lot anywhere from 120 degrees to around 95 during peak summer.