Vented Attic Vs Unvented Attic

Sealed attic vs vented attic.

Vented attic vs unvented attic.

Which is best for your home. Control of ice dams moisture accumulation and heat gain can be successfully addressed by both vented and unvented attic or roof design. However the designs need to be climate sensitive. To finish an unvented cathedral ceiling insulated with closed cell foam most codes require a layer of 1 2 inch drywall or an equivalent thermal barrier top.

Deciding to upgrade your attic insulation to include spray foam insulation like icynene is a step toward energy efficiency and a more comfortable home. Both vented and unvented attic roof designs can be used in all hygro thermal regions. Choosing a conditioned attic vs unconditioned attic space comes down to what you want to do with the area and what works best with the design of your home. 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.

Removing moisture from roof cavities structural members sheathing and insulation. Section r806 4 unvented attic assemblies. Vented roofs serve a number of different purposes and their roles vary from climate to climate. Unvented roofs vented roof.

In colder climates the main purpose of a vented roof is to keep the roof cold and reduce the formation of ice dams. In this case you can learn a lot from foam tech s article vented vs. Unvented attics when insulating an unvented roof assembly prefers closed cell to open cell foam because it s both an air barrier and a vapor retarder. But with vented and unvented attics both being options that are available how do you know which one is right for your home.

This section outlines the conditions for unvented attic roof assemblies. The choice of the venting approach is up to the designer. May 11 2015 2 26pm. Note that this would not apply where an unvented roof assembly is used as indicated in section r806 4.

A vent space clearance of at least 1 must be maintained at the location of the vent and between insulation and roof sheathing. Enhancing roofing material life span by reducing sheathing temperature. A secondary goal is to vent moisture that infiltrates the attic from the conditioned home. Unvented roofs which provides a detailed explanation of each.

Controlling ice damming by keeping the roof cold.