Vented Vs Unvented Attic

This section outlines the conditions for unvented attic roof assemblies.

Vented vs unvented attic.

Requirements for unvented attic assemblies are provided in section 0806 4 of the international residential code 2009 irc. If you must have the hvac equipment in a vented attic pay special attention to duct insulation chapter 9. Let s dive a little deeper into what that means exactly. Unvented may 11 2015 2 26pm deciding to upgrade your attic insulation to include spray foam insulation like icynene is a step toward energy efficiency and a more comfortable home.

Section r806 4 unvented attic assemblies. In an unvented assembly anything below the insulation including an attic is considered conditioned space. Note that this would not apply where an unvented roof assembly is used as indicated in section r806 4. The choice of venting or not venting is a design and construction choice not a requirement determined by the physics or by the building code.

Codes for unvented attics. Unvented roofs which provides a detailed explanation of each. A properly constructed unvented attic is immune to the moisture problems that occur in vented assemblies and is much more likely to be energy efficient. Attics or roofs can be designed and constructed to be either vented or unvented in any hygro thermal zone map 1.

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. Attics vented vs. In this case you can learn a lot from foam tech s article vented vs. The model building codes allow both vented and unvented roof assemblies.

Vented roofs vented roofs serve a number of different purposes and their roles vary from climate to climate. It has been shown that ventilation has a great effect on the attic air temperature but much less on shingle temperature. A vented attic system refers specifically to having working vents in the attic. Don fugler research director canada mortgage and housing corporation.

Airtight ceilings are a more reliable way to ensure a dry attic than venting but in practice most houses fall into a middle ground where venting balances moisture input. Researchers have compared the shingle temperature of both vented and un vented roof systems.