Vented And Unvented Roof Assembly

Moisture content in roof structure must be less than 18 prior to covering.

Vented and unvented roof assembly. Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction. Because the drying capacity of unvented roof assemblies is inherently lower than vented ones it is especially critical to control built in moisture during construction. They are designed without ventilation openings and the attic is conditioned like the rest of the living space. Vented roofs vented roofs serve a number of different purposes and their roles vary from climate to climate.

An unvented assembly can perform well but it s important to get the details right to avoid sheathing rot. These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck. Sc historically typical construction of homes in canada and the us have vented attics between the ceiling of the interior space and the roof. An unvented roof assembly is constructed without any ventilation and is fully sealed on all sides and filled with insulation.

Control construction moisture content with tenting or temporary roofing when necessary.