Vented And Unvented Roof Assembly

Vented roofs vented roofs serve a number of different purposes and their roles vary from climate to climate.

Vented and unvented roof assembly.

An unvented assembly can perform well but it s important to get the details right to avoid sheathing rot. 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. An unvented roof assembly is constructed without any ventilation and is fully sealed on all sides and filled with insulation. Moisture content in roof structure must be less than 18 prior to covering.

Unvented roof assemblies are becoming an increasingly common construction alternative to traditional vented roofs. These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck. Control construction moisture content with tenting or temporary roofing when necessary. 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.

Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction.