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Venting Soffit / Overhang

I'm presently building a house with a flat TJI roof. Over the living space there is sloped foam that provides the R-value for the roof as well as the slope. Above the overhang is simply 5/8" T&G followed by torch on. Above the exterior wall separating the overhang space from the "attic" space is blocking sealed with DOW XPS and spray foam. The underside of the overhang will be stained T&G Pine.

My question is, does the overhang cavity need to be / should it be (or not be) vented?

Thank you for your help!


Asked by Brandon Kennedy
Posted Apr 5, 2017 6:45 PM ET


1 Answer

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It sounds like you are describing an unvented roof assembly. If I am guessing correctly -- it's a little hard to tell from your description -- then you don't need soffit vents (because the assembly is unvented).

I hope that your designer and roofer have installed enough insulation to at least meet minimum code requirements. Depending on your location, that usually means either R-38 or R-49 insulation.

For more information on these issues, see Insulating Low-Slope Residential Roofs.

-- Martin Holladay

Answered by Martin Holladay
Posted Apr 6, 2017 6:23 AM ET

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