Roof Venting Vaulted Ceiling

Sketch above showing venting in a steep slope cathedral ceiling roof is courtesy of carson dunlop associates.

Roof venting vaulted ceiling.

Foam filled cathedral ceilings may make sense in some cases. This all per code here in southern oregon. If you fill a bay in a vaulted ceiling no vent is required. The only way to do that are gable vents for intake and ridge for exhaust.

Only the air space that exist at the peak if any needs venting. How to vent a vaulted roof vaulted roof elements. To understand the necessity of proper ventilation it helps to have a basic. The bottom of each rafter cavity ends at the soffit which is the horizontal plane that lies just beneath.

Now here is the contradictory part. The flow of water vapor. A vaulted roof features angled rafters that rest on wall plates and connect at the top to a ridge. Cathedral ceilings built using 2 x 12 roof rafters allow enough space for the fiberglass batt insulation and a 1 5 gap for ventilation.

Ventilating cathedral ceilings step 1. 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. In the case of a cathedral vault where the interior ceiling is parallel to the exterior roof line installing skylights is a simple process. Sealing bypasses the first line of defense.

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. Attic bypasses are hidden air passageways that lead from the. These assemblies pose unique ventilation problems. Vented cathedral ceiling assemblies incorporate soffit or eave vents adequate open air space between insulation and roof deck sheathing and ridge vents.

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. Cathedral ceiling ventilation insulation if properly installed between the rafters on top of the ceiling material drywall plaster paneling sheets etc there should be approximately 2 of space left above it which allows air to flow between the bottom and top of the roof.