Unvented Roof Design

An unvented superinsulated roof by martin holladay issue 224 deck for a thick roof rigid foam insulation installed above the roof assembly can create an energy smart roof.

Unvented roof design.

An understanding of heat air and moisture as well as the causes of condensation is critical in detailing unvented roof assemblies. Un ven ted roof ˌənˈven t əd ro of an unvented roof assembly is constructed without any ventilation and is fully sealed on all sides and filled with insulation. Unvented metal roof ted storm posted in energy efficiency and durability on april 27 2011 09 53am in the process of construction currently have a standing seam metal room installed over synthetic felt over osb. Unvented roofs operate by the principle that venting is not necessary to control moisture accumulation.

This document provides a brief description of different types of unvented roof assemblies and the benefits of unvented roof construction. Potential pitfalls to avoid include. Designs and houses with unvented roof insulation systems have also been developed and constructed in cold and mixed climates. The optimum systems developed to date are dependent on the climate location.

Over the past five years several unvented roof insulation systems have been developed by the building science consortium for use primarily in hot dry and hot humid climate zones. These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck. Unvented roofs also make a lot of sense in high wind or high fire areas where vents might admit drenching rains or embers. Sc historically typical construction of homes in canada and the us have vented attics between the ceiling of the interior space and the roof.

Ventilation becomes more difficult the more complicated a roof s construction is. They are designed without ventilation openings and the attic is conditioned like the rest of the living space. Unvented roofs unvented roofs are increasingly common due to design priorities. Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction.

Unvented roof here again the choice of what insulation to use and whether to install it over or under the roof deck depends on the condition of the present roof the depth of rafters the r value you must attain and cost.