Vented And Unvented Roof Assembly

In other words vented roofs may well be the best design for one home while an unvented roof will be a better solution for another home.

Vented and unvented roof assembly.

Moisture content in roof structure must be less than 18 prior to covering. 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. These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck.

An unvented roof assembly is constructed without any ventilation and is fully sealed on all sides and filled with insulation. Sc historically typical construction of homes in canada and the us have vented attics between the ceiling of the interior space and the roof. Vented roofs vented roofs serve a number of different purposes and their roles vary from climate to climate. They are designed without ventilation openings and the attic is conditioned like the rest of the living space.

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.