Vaulted Ceiling Unvented Cathedral Ceiling Insulation

The last time you posted comments on your roof on 4 8 2014 when you posted comment 6 on the q a thread titled insulating unvented cathedral ceiling dana dorsett and i provided several possible explanations for why your cathedral ceiling is dry.
Vaulted ceiling unvented cathedral ceiling insulation. 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. Tips for insulating a cathedral ceiling take care to seal ceiling penetrations such as around light fixtures. If installed properly it will create an effective air and vapor barrier to keep interior moisture away from the roof sheathing where it can condense and cause problems. Insulating cathedral ceilings can be quite challenging.
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. Unvented roof assemblies such as conditioned attics and unvented cathedral ceilings are becoming common in north american construction. An unvented assembly can perform well but it s important to get the details right to avoid sheathing rot.
Regarding the roof insulation closed cell foam is the best product to use for an unvented cathedral ceiling. 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. Cathedral ceilings provide a majestic crown for many a great room but insulating them can be tricky. Our photo illustrates water trapped in an un vented vaulted ceiling from wbhich cedar paneling has been removed.
Attic trusses typically have a sloping ceiling. Insulating an unvented cathedral ceiling. 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. It is estimated that over 100 000 have been constructed since 1995.
The new workshop will be located over my garage in an area that was framed using attic trusses when we built the new house.