Of course, attics require proper ventilation. Does that rule still apply to a vaulted ceiling with steel roofing? I would think so, don’t you? This roof is completely sealed up.
Is it closed cell spray foam insulation? If so, venting isn’t necessary. Whether the AHJ requires it or not is a separate issue though.
2 Likes
Ah, yes, that makes sense, thank you. Unfortunately, I am not sure how I could verify that.
Where are you located Bryan?
That is some beautiful scenery.
As for your question, yes, IMO it still should be vented to prevent super heating of everything below the roof surface and condensation from forming and causing damage.
2 Likes
If not closed cell foam, I, personally, think there could be a condensation issue. See below (and in other web locations):
What happens if you don’t vent a metal roof?
Moisture in the air that accumulates near the roof will be a recipe for disaster over time. That’s because it can allow for mold, mildew, and condensation to build up around the roof and even in the walls or ceiling.Apr 21, 2021
From:
Does A Metal Roof Need To Be Vented? | Mountaintop Metal Roofing.
3 Likes
Location: on the Poudre River near Fort Collins, Colorado 
.
1 Like
Just depends if it is sealed insulated roof space or was meant to be vented space. How would you know at this point? You could direct the buyer to the seller or builder for design plans etc. Unvented cathedral is considered a hot roof design which does have some drawbacks. The metal roof is one of the better materials in my opinion for this.
Good article.
5 Likes
Good graphic Brian. Most all I see in my area are of the “sealed” type, but of course it’s almost impossible to determine the type of insulation used. From most all the construction I’ve seen before on this type of vaulted ceiling, they used ridged foam board under the roof sheathing with no gap between interior ceiling finish, being drywall or wood plank.
3 Likes
Sealed infers airtight and that is a tough hurdle to get over for a roof assembly. Airtight j-boxes, vent penetrations, perfect caulking inside and out…just sayin’ that’s tough to do and tougher to maintain. I think designing a vented space, is likely to be more forgiving.
3 Likes