Unventilated Roof Construction

Poorly insulated ducting can cause heat loss in colder months and the loss of conditioned air in the summer in vented attics.

Unventilated roof construction.

Control construction moisture content with tenting or temporary roofing when necessary. Eliminates large cool voids within the construction reducing thermal stress. Cold roof decks and external cladding or tiling. Breather membrane in colours.

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. These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck. Eliminating traditional ventilation and the potential condensation risk associated with large voids of cool air make this the optimum pitched roof solution. This document provides a brief description of different types of unvented roof assemblies and the benefits of unvented roof construction.

Together with not having to provide a ventilation pathway the technique permits insulation to be installed within the full depth of the rafter. For designers the advantage of using unventilated construction comes from removing the necessity to provide a ventilated cavity below the sarking. Unventilated attics are common where roof assemblies are complex and it s difficult to create a sealed ceiling plane.