Vented Vs Unvented Roof

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.

Vented vs unvented roof.

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 a vented roof foam can seal the openings and serve as an air barrier and a vapor retarder in addition to its insulating function. A vented attic system refers specifically to having working vents in the attic. In other words the entire vent opening doesn t count as vented space.

Let s dive a little deeper into what that means exactly. In areas subject to wildfires burning embers can be blown in through these openings potentially starting roof fires. Unvented roofs which provides a detailed explanation of each. That said air resistance and interference such as vent grates reduces the area of true ventilation.

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. Control construction moisture content with tenting or temporary roofing when necessary. 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. 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. Vented roofs vented roofs serve a number of different purposes and their roles vary from climate to climate. In coastal climates wind driven rain can be blown in through these openings with similar results. Control of ice dams moisture accumulation and heat gain can be successfully addressed by both vented and unvented attic or roof design.

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. The choice of the venting approach is up to the designer. 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.