Unvented Cathedral Ceiling Insulation

Worries about the hot roof un vented cathedral ceiling designs how to.

Unvented cathedral ceiling insulation.

Air permeable insulation such as fiberglass batts dense packed cellulose or blown in fiberglass can t be used alone for an unvented assembly since these types of insulation can allow moist indoor air to reach the cold roof sheathing leading to condensation or moisture accumulation. How to avoid condensation leaks attic mold insulation mold structural damage to roof framing when roof venting is not possible cathedral roof and knee wall insulation venting air path options in older homes hot roof designs. Martin s post focuses on the marketing of owens corning 039 s propink unvented attic insulation system. 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.

Yes unvented roof assemblies can be insulated with fiberglass a wufi post and not just in climate zones 2b amp. If you choose sistering 2x10 s then they have a net depth of 9 1 4. A poorly detailed cathedral ceiling can lead to energy losses and rotted roofing. These assemblies are created by eliminating ventilation openings and moving the thermal moisture and air control boundaries to the plane of the roof deck.

Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction. Regarding the roof insulation closed cell foam is the best product to use for an unvented cathedral ceiling. Insulating an unvented cathedral ceiling. So your choices are 3 1 2 thick batt insulation for an r value of about r 11 9 or rigid insulation board for a r 20 to r 30 depending on the type of board.

Suggestions for un vented or hard to vent building roof cavities. 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. In this article senior editor martin holladay describes eight ways to get a cathedral ceiling roof to r 45 or better using both vented and unvented. Our summers in northern california can be pretty hot amp i am looking to add more insulation to my attic the attic floor is insulated already there is a ridge vent there are 2 gable vents 1 has a fan there are 2 between rafter vents.

Therefore leaving about 1 for venting the net depth of insulation should be about 8 or so.