Venting at “Soffit Area” in a Roof with No Soffit
I am retrofitting a recently acquired summer cottage in Southern Ontario in order to make it more user friendly for year round use.
The roof has fibreglass insulation inside of degrading plastic covering haphazardly laid in the joists of the attic floor. (The plan is to remove them so I can see what air sealing needs to be done before re-insulating with blown-in cellulose.)
I am trying to find the best way to follow vented roof protocol, but there are no soffits. That is, the top of the exterior walls join the bottom of the roof. There is a large roof overhang (no eaves) but there is no return of this overhang to join back to the wall. Ridge vents are present at the top of the roof.
In order to maintain the facade of the building, I would prefer not to do any alterations to the exterior trim in order to create a soffit.
In the front of the cabin roof there is an aesthetic gable with a window. The bottom of the window lines up with the bottom of the gable and the bottom roof line. The window is about 2.5’ x 2.5’ in size. The roof base is about 1500 square feet. The pitch of the roof is “medium”, and is a square pyramid in shape (other than the gable).
Is this window sufficient to vent the entire roof from below? That is, would it provide enough “soffit venting”?
There are also scattered small, nominal gaps in the roofing where the exterior walls meet the bottom roof line, which would also provide some “soffit ventilation” too, I would imagine.
The next challenge will be finding a way to baffle the ventilation at the bottom roof line to keep it from being obscured by the blown in insulation.
Thanks for any input.
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