Unvented Porch Roof With Finished Ceiling

An unvented roof assembly is possible only if you keep the roof sheathing warm enough to prevent conditioned air from condensing against it.

Unvented porch roof with finished ceiling. We ended up buying bamboo fencing and stapled it up. Porch roof ventilation options. I know you ve already started but wanted to add my 2 cents. We connected a screened porch to the main house with a small foyer addition roughly 10 x 20 that has an insulated concrete slab on grade floor electric nuheat mat planned under porcelain tile flooring 2 6 exterior wood stud walls and 2 12 sloped rafters 16 o c.

Roof vents help make a home more energy efficient and allow humidity and hot air to escape the. If you don t want to use sips or nailbase read this article tolearn the four basic approaches to insulating unvented roof assemblies. We then bought some quarter round to finish the edges. Where the attic space is finished with drywall or other ceiling materials installed against the underside of the roof rafters while we prefer in floor insulation here we ll have to insulate the roof cavity between the rafters.

These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck. Since there is no venting i m thinking of using pink styrofoam against the underside of the decking before putting up the finished ceiling. The house was built in 1880s and the porch probably about 1900. Unvented roof assemblies should be insulated either with air impermeable insulation rigid foam or spray polyurethane foam or with a combination of foam and air permeable insulation.

I installed collar ties to leave an open space above the finished room along with r 15 insullation and installed a fan on a thermostat at the end of the roof in addition to ridge vent to suck all the hot air that collected between the roof and porch ceiling. We had an ugly porch ceiling that had some previous water damage that was repaired poorly painting wasn t an option for us. Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction. With a 3 12 pitch to form an unvented cathedral ceiling.

The map at right which is based on table r806 4 of the irc lists the minimum r values required to prevent condensation in unvented assemblies in various climate zones. Un vented hot roof designs indoors finished attic. The decking is 2 12 or larger with a metal roof at a 4 12 pitch to the side of the house. An unvented roof assembly is constructed without any ventilation and is fully sealed on all sides and filled with insulation.