Unvented Cathedral Ceiling Metal Roof

An under roof cathedral ceiling or attic ventilation system to help the building in any way needs to be properly designed and installed with adequate intake venting at the eaves outlet venting at the ridge and with careful sealing of air leaks from the occupied space into the attic or roof cavity to avoid heat losses or increases in both.

Unvented cathedral ceiling metal roof. Below is 1x decking and 2x4 rafters. An unvented assembly can perform well but it s important to get the details right to avoid sheathing rot. Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction. Flat roof cathedral ceiling we re going to give it a try.

Worries about the hot roof un vented cathedral ceiling designs how to. Suggestions for un vented or hard to vent building roof cavities. With an unvented cathedral ceiling it is critical to keep moist air and water vapor away from the roof sheathing where it can build up and lead to wood decay. Existing is a fourteen year old roof with 2 of closed cell roofing foam with an acrylic elastomeric coating.

A conditioned attic designed to protect ductwork from extreme temperatures is another. 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. One of the best ways to insulate a roof whether sloped or flat is to install rigid foam on top of the roof sheathing. 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.

A cathedral ceiling over a great room is a common example. Additionally an unvented roof assembly is safer in areas exposed to wildfires. Send your questions to tom. Get help with your home improvement projects.

These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck. Our plan is to put rigid board up between the 2x4 s caulk the edges and then hang sheetrock.