Roof Venting Vaulted Ceiling

Cathedral ceilings built using 2 x 12 roof rafters allow enough space for the fiberglass batt insulation and a 1 5 gap for ventilation.

Roof venting vaulted ceiling.

This type of roof assembly is designed so the air can flow up the soffit vent through an insulation baffle pass through the 1 5 gap between the insulation and roof sheathing then exit through a ridge vent. These assemblies pose unique ventilation problems. To understand the necessity of proper ventilation it helps to have a basic. The question and answer article below paraphrases quotes from updates and comments an original article from solar age magazine and written by steven bliss.

Sketch above showing venting in a steep slope cathedral ceiling roof is courtesy of carson dunlop associates. Attic bypasses are hidden air passageways that lead from the. The bottom of each rafter cavity ends at the soffit which is the horizontal plane that lies just beneath. Vaulted ceilings sometimes referred to as cathedral ceilings occur in steep slope roof assemblies in which there is no attic space between a ceiling and roof deck.

The only way to do that are gable vents for intake and ridge for exhaust. Sealing bypasses the first line of defense. The flow of water vapor. How to vent a vaulted roof vaulted roof elements.

This all per code here in southern oregon. In the case of a cathedral vault where the interior ceiling is parallel to the exterior roof line installing skylights is a simple process. Only the air space that exist at the peak if any needs venting. In buildings where there is no roof venting anyway and where ventilation is difficult or impossible to achieve an un vented well insulated hot roof can provide a high r value ceiling and may be the second best alternative to preventing ice dam related leaks in cold climates.

Click to enlarge any image. A vaulted roof features angled rafters that rest on wall plates and connect at the top to a ridge. Now here is the contradictory part. Ventilating cathedral ceilings step 1.

Vented cathedral ceiling assemblies incorporate soffit or eave vents adequate open air space between insulation and roof deck sheathing and ridge vents. If you fill a bay in a vaulted ceiling no vent is required.