Unventilated Roof Construction

Unventilated attics are common where roof assemblies are complex and it s difficult to create a sealed ceiling plane.

Unventilated roof construction.

Control construction moisture content with tenting or temporary roofing when necessary. Breather membrane in colours. Eliminating traditional ventilation and the potential condensation risk associated with large voids of cool air make this the optimum pitched roof solution. Together with not having to provide a ventilation pathway the technique permits insulation to be installed within the full depth of the rafter.

Cold roof decks and external cladding or tiling. For designers the advantage of using unventilated construction comes from removing the necessity to provide a ventilated cavity below the sarking. Eliminates large cool voids within the construction reducing thermal stress. This document provides a brief description of different types of unvented roof assemblies and the benefits of unvented roof 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. 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. Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction.