Roof Insulation Vaulted Ceiling Unvented

Suggestions for un vented or hard to vent building roof cavities.

Roof insulation vaulted ceiling unvented.

Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction. If installed properly it will create an effective air and vapor barrier to keep interior moisture away from the roof sheathing where it can condense and cause problems. These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck. Senior engineer manager at icynene john broniek makes the case for the unvented attic assembly and why insulating the underside of the roof makes sense.

As with cathedral ceilings the insulation is in the rafters and or the roof deck. The primary benefit of cathedralized attics is the ability to locate hvac ducts inside conditioned space where. Martin s post focuses on the marketing of owens corning 039 s propink unvented attic insulation system. Air permeable insulation such as fiberglass batts dense packed cellulose or blown in fiberglass can t be used alone for an unvented assembly since these types of insulation can allow moist indoor air to reach the cold roof sheathing leading to condensation or moisture accumulation.

An unvented assembly can perform well but it s important to get the details right to avoid sheathing rot. Worries about the hot roof un vented cathedral ceiling designs how to. You could leave the ceiling insulation in place providing some additional insulation for the living space below. Install insulation along the underside of the roof deck of an unvented attic rather than on the ceiling deck of a vented attic for either of two reasons.

Regarding the roof insulation closed cell foam is the best product to use for an unvented cathedral ceiling. Verify that roof insulation installed under the roof sheathing is well supported. If you want the attic to be conditioned space that is heated and cooled then your best bet would be an unvented cathedral ceiling sometimes referred to as a hot roof. Unvented attic assemblies code notes 2009 irc 2012 irc.

How to avoid condensation leaks attic mold insulation mold structural damage to roof framing when roof venting is not possible cathedral roof and knee wall insulation venting air path options in older homes hot roof designs.