Unvented Finished Attic

To provide an unvented conditioned space for locating hvac equipment in the attic and or to provide a continuous thermal barrier for designs that have complex coffered ceiling planes and or numerous penetrations for lights speakers vents soffits etc which make it difficult to achieve an airtight ceiling plane.

Unvented finished attic. Unventilated attics can help to mitigate energy loss through leaky ducts or ceiling fittings. An unvented attics is one where the air vapor and thermal controls are installed at the roof deck. By using an air impermeable insulation like spray foam on the roof deck will stop any air movement. The alternative is to have an unvented attic which means including the attic in the conditioned area of your home and keeping moisture out.

An unvented attic is one which is not ventilated and this is important one where the ceiling has complete air vapor and thermal controls in place. Poor insulation is usually the culprit although if you enter the attic on sunny winter day your attic space can be warmed by the sun more than your furnace. Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction. 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.

Attics or roofs can be designed and constructed to be either vented or unvented in any hygro thermal zone map 1. Unless your roofing system has insulation on the roofing deck and is designed without ventilation your furnace should not be heating your attic. The energy savings touted by unvented attics can be as high as 20. The model building codes allow both vented and unvented roof assemblies.

An unvented attic system relies on an air seal and no vents to make the attic a conditioned space. Install insulation along the underside of the roof deck of an unvented attic rather than on the ceiling deck of a vented attic for either of two reasons. These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck. Openings between the attic and the outside are sealed and the underside of the roof is insulated.

Energy savings an unvented attic is warmer in winter and cooler in summer reducing the hvac load. And i mean completely intact.