Unvented Shed Roof With Above Deck Installation

Yes skylights went in.

Unvented shed roof with above deck installation.

Yes they are big thermal holes. Warm wet air rises and meets the cold roof and cools. Photograph 1 above left. With rigid foam above the sheathing and cellulose in the rafter cavities this roof is about r 63.

Of cellulose insulation in the rafter cavities the roof shown here has an r value of approximately 63. But a space needs to be a space or what is the point. Four options for building an unvented roof assembly. The three layers of foam help to seal air leaks but to make this assembly perform well you need to incorporate some unconventional details.

As it cools it can t hold as much moisture. Martin s post focuses on the marketing of owens corning 039 s propink unvented attic insulation system. Rigid foam insulation installed above the roof assembly can create an energy smart roof. Deck for a thick roof rigid foam insulation installed above the roof assembly can create an energy smart roof.

Test roofing membranes for integrity prior to covering from below. Furring straightens out rafter plane for smooth plaster finish. Dallas tx is located in a mixed humid climate region. Rigid foam above roof sheathing.

Yes unvented roof assemblies can be insulated with fiberglass a wufi post and not just in climate zones 2b amp. Another approach is to build a cupola or ventilated doghouse in the middle of the low slope roof an approach championed by joe lstiburek. Note that this roof assembly has rigid insulation installed above the roof deck in order to control the condensation potential. You can install all of the insulation above the roof sheathing but the foam has to be thick enough to meet minimum code requirements for ceiling r value.

Unvented roof diagram i know this is a very basic example so if you want to read more on the topic i ve put some additional reading for unvented roofs at the end of this article. Polyisocyanurate insulation above the sheathing and approximately 91 4 in. In unvented flat or low slope roofs with parapets perform a full flood test to ensure leak free installation of roofing membrane. Simply put unvented roofs get rid of the vents and move the thermal air control and moisture boundaries to the roof deck.

This roof assembly has no insulating sheathing installed above the roof deck. Original roof uninsulated rafter framing with board roof deck. That excess moisture ends up as drops of condensation on the roof. If the upper edge of a low slope shed roof intersects a vertical wall the most logical approach in my opinion is to detail the roof as an unvented roof.

The rigid foam will be fairly thick see sidebar how much insulation. With three layers of 11 2 in. Drying of unvented roofing assemblies is by definition only provided to the interior.