Vented Vs Unvented Roof

In a vented roof foam can seal the openings and serve as an air barrier and a vapor retarder in addition to its insulating function.

Vented vs unvented roof.

Control construction moisture content with tenting or temporary roofing when necessary. In other words the entire vent opening doesn t count as vented space. Vented attic roof designs have the advantage of a long proven historical track record. In other words vented roofs may well be the best design for one home while an unvented roof will be a better solution for another home.

When insulating your attic the contractor can either spray the attic floor to keep a vented attic or spray the roof deck for an unvented system. Control of ice dams moisture accumulation and heat gain can be successfully addressed by both vented and unvented attic or roof design. Basically the term cold roof refers to a traditional roof or vented roof while hot roof refers to a roof that is not ventilated and which has foam insulation attached directly to the roof sheathing. In coastal climates wind driven rain can be blown in through these openings with similar results.

The choice of the venting approach is up to the designer. Too many people believe the importance of roof ventilation is to increase energy efficiency during the summer. Inclined along the line of rafters warm roof or positioned within the roof structure to form an insulated void room in roof which can result in warm and cold roof areas. In areas subject to wildfires burning embers can be blown in through these openings potentially starting roof fires.

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. Vented roofs vented roofs serve a number of different purposes and their roles vary from climate to climate. A vented attic system refers specifically to having working vents in the attic. That said air resistance and interference such as vent grates reduces the area of true ventilation.

Unvented roof assemblies are not prone to these problems because the ventilation openings have been eliminated. In this case you can learn a lot from foam tech s article vented vs. In an un vented roof foam can serve as the air barrier and vapor retarder and prevent moisture from getting in to the roof cavities. In pitched roof construction thermal insulation can be placed horizontally at ceiling level cold roof.