Unvented Flat Roof

Insulation and air barrier are applied directly to the underside of the roof deck are common in applications where designers are seeking cost effective and energy efficient roof assemblies.

Unvented flat roof.

Martin s post focuses on the marketing of owens corning 039 s propink unvented attic insulation system. Low slope and steep slope unvented roof systems i e. In unvented flat or low slope roofs with parapets perform a full flood test to ensure leak free installation of roofing membrane. Unvented roof assemblies should be insulated either with air impermeable insulation rigid foam or spray polyurethane foam or with a combination of foam and air permeable insulation.

Drying of unvented roofing assemblies is by definition only provided to the interior. Yes unvented roof assemblies can be insulated with fiberglass a wufi post and not just in climate zones 2b amp. Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction. If you don t want to use sips or nailbase there are four basic approaches.

These roofs can lower your heating costs in the winter. Un vented roofs operate on the principle that moisture entering the roof assembly can be controlled and that there is no need for venting to control moisture accumulation. When properly installed unvented roofs perform well and cause no excess moisture accumulation. In order for an un vented roof assembly to function properly the following conditions must be in place.

Unvented roof design falls into two categories. Four options for building an unvented roof assembly. Unvented flat roofs a technical discussion flat roofs have often been built with the insulation all on top of the vapor closed drainage plane as this avoids dew point condensation issues inboard of the roofing. This document provides a brief description of different types of unvented roof assemblies and the benefits of unvented roof construction.

However architects of these compact roof assemblies must consider vapor permeance and arrangement of the materials to produce acceptable hygrothermal performance and low risk of condensation in the resulting conditioned attic space.