Vented And Unvented Roof Assembly

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.

Vented and unvented roof assembly.

An unvented roof assembly is constructed without any ventilation and is fully sealed on all sides and filled with insulation. An unvented assembly can perform well but it s important to get the details right to avoid sheathing rot. Vented roofs vented roofs serve a number of different purposes and their roles vary from climate to climate. 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.

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. Control construction moisture content with tenting or temporary roofing when necessary. They are designed without ventilation openings and the attic is conditioned like the rest of the living space. Sc historically typical construction of homes in canada and the us have vented attics between the ceiling of the interior space and the roof.

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