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VENTING cathedral ceiling without a soffit vent.

olandsns | Posted in Building Code Questions on

What is best practice for venting a cathedral ceiling where I cannot have a soffit vent? or, what measures do can I take to prove that venting is unnecessary? 

Our lower eave is within 1.2m of the property line which means we cannot have openings/vents in our soffit. Either we put a roof top vent in every rafter cavity, top and bottom, install purlins and vent top and bottom. 

Seems like it may be easier to not vent, if only I new what the building inspector was looking for.

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  1. Expert Member


    Building codes allow unvented roofs. They insulated differently than vented ones. This article may help.

  2. Expert Member
    Akos | | #2

    When you are that close the the property line, you generally can't have openings in the walls. You can have openings into the roof though. Vented roofs near property line are very common around me.

    OBC allows for unvented roofs provided you have the right amount of rigid insulation in the 4000 HDD area that is around 1/3 of overall R value rigid above the deck and 2/3 fluffy bellow.

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