Finishing An Unvented Attic

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.

Finishing an unvented 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. The roof deck in an unvented attic must be exceptionally airtight. A fundamental requirement of an unvented attic assembly is the use of air impermeable insulation on the underside of the unvented roof to prevent air infiltration and exclude airborne moisture from the attic. Both vented and unvented attic roof designs can be used in all hygro thermal regions.

But in many spray foamed attics it can be hard to manage humidity. I have a shop in my attic for some of my hobbies and it get s very hot in the summer. The choice of the venting approach is up to the designer. This air seal will help to make your home more energy efficient.

However the designs need to be climate sensitive. Closed cell is a vapor retarder meaning water from a leak could be trapped against the roof sheathing. Code requirements vary across the country. 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.

I have large attic with ridge vents and screened vents at either end of the attic to maintain air flow. Once an unvented roof is finished it s awfully damn difficult to notice roof leaks. The energy savings touted by unvented attics can be as high as 20. The irc has permitted unvented conditioned attics since 2006 with certain requirements.

Unvented attic system pros and cons. Unventilated attics can help to mitigate energy loss through leaky ducts or ceiling fittings. If you want you can even transform a spray foamed attic into a finished space. Control of ice dams moisture accumulation and heat gain can be successfully addressed by both vented and unvented attic or roof design.

Can i put a small swamp cooler or ventless a c unit up there to cool it only to use while i am in my shop maybe an hour or two a couple times a week. However if moisture is able to enter the unvented attic space it may lead to roofing panel issues. The acceptance of unvented conditioned attics continues to grow among builders and building officials. The unvented attic system or conditioned attic is the new way to make your attic energy efficient.

The attic space becomes indirectly conditioned as a result of the air leakage heat transfer and vapor diffusion through the ceiling.