Unvented Attic Space

Making the attic a conditioned space means the space will be the same temperature as the rest of your home.

Unvented attic space.

This air seal will. The unvented attic space is completely contained within the building thermal envelope 2. The entire attic becomes conditioned space eliminating drafts and temperature fluctuations. Adding unvented attic insulation like spray foam seals the building envelope and stops airflow.

No interior vapor retarders are installed on the ceiling side attic floor of the unvented attic assembly 2009 irc. An unvented attics is one where the air vapor and thermal controls are installed at the roof deck. Unventilated attics can help to mitigate energy loss through leaky ducts or ceiling fittings. The unvented attic is indirectly conditioned space since heat and moisture transfer occurs through the top floor ceiling particularly if the ceiling is not airtight.

There are typically no supply or return registers from the hvac system specifically located in an unvented attic space. No interior class i vapor retarders are installed on the ceiling side attic floor of the unvented attic assembly or on the ceiling side of the unvented enclosed rafter assembly. Unvented attic roof designs have the advantage of providing conditioned spaces for ductwork and air handlers. In cold climates attic ventilation is a common method to remove humid air.

Air does not flow into the soffits and does not flow out of ridge or gable vents. Section 1203 3 says unvented attics where ceilings are applied directly to the underside of the roof framing members are permitted when all of the following conditions are met. However they require different approaches in different climate locations. The energy savings touted by unvented attics can be as high as 20.

However if moisture is able to enter the unvented attic space it may lead to roofing panel issues. The unvented attic space is completely within the building thermal envelope. In hot climates unvented attics are ideal where hvac equipment and ductwork are located in the attic. No interior class i vapor retarders are installed on the ceiling side attic.

Modifying the attic to create an indirectly conditioned attic space with icynene can significantly reduce energy consumption.