Flat Roof Non Venting Methods

Unvented roofs which provides a detailed explanation of each.

Flat roof non venting methods.

The range of materials includes an elastomeric paint large polyvinyl chloride pvc sheets with heat sealed seams an asbestos film shield or even a thin layer of solar panels that will collect solar energy. In this case you can learn a lot from foam tech s article vented vs. The article notes that the ventilation cannot overcome the significant humidity drive into the flat roof structure caused by small air leaks. The intent of roof venting varies depending on climate but it is the same if you re venting the entire attic or if you re venting only the roof deck.

In a cold climate the primary purpose of ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow and to vent any moisture that moves from the conditioned. 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. Specialized roof coatings are available in a wide range of materials and can help a flat roof reflect up to 90 percent of solar heat. In order for an un vented roof assembly to function properly the following conditions must be in place.

On a warm flat roof the layer is installed underneath the insulation to stop moisture interacting with it through rising thermal pressure lower down in the building. Consequently the article concludes that the concept of venting a flat roof is no longer safe and instead don t vent the flat roof and install a smart vapor retarder inboard.