Vent config for low-slope roof butted against wall


Hi. Just wondered if anyone has a thought on this design I’m thinking of building. The main roof is 1/12, the low side is on the south side of the building, and slopes up the north. At the north side, the roof meets a wall. How do I configure a exhaust vent a the north(top) of this roof that will not be prone to water entry or snow coverage. The roof section will be 72x25, so the vent will extend across the 72’length. The house is illustrated on , for a visual guide Thanks :smiley:

Craig K


Craig, at 1/12 roof pitch you are going to have to build a curb next to the wall to vent that area. Run your flat roofing up the curb and install a custom made vent and flashing to cover. You might be able to use a pre made vent like DCI smart vent against the wall.


Would be best to post a pic of the specific area you’re talking about and the type of material you will be using. Also, are you looking for general roof ventilation or something for a stove maybe? Either way much of your commercial application is low slope so I don’t see any unique problem in getting a vent. Just google “commercial roof vent” or something of that nature; no reason to re-invent the wheel.


they make a metal clerestory vent that buts the wall


Thanks for the input Guys! The building inspector in my area has concerns about water entry and snow accumulation with a vent installed at the junction of the roof and the clerestory wall. Do you think I can install something that will take care of those concerns? Thanks alot!


The vent would be for general roof ventilaion and the roof copvering will be torchdown.


Ok, great picture. First of all you should be talking to a person that specializes in commecial flat roofs.

I would not build a curb against the wall. I would vent that roof as a commercial application. Even if you did build a curb to vent against the wall you would have to divide it because of the windows, which leaves you with an uncontiguous design, leaving some bays unvented. Before I did that I would place the vents in the wall between the window placements and make sure the open bays under the roof extended up the wall a couple feet to the vents.

Talk to a commercial expert (which I am not) and seek his advice on ventilation. I would also strongly consider a EPDM fully adhered application in lieu of torch down. Also note that neither Torch application or EPDM will carry a manufacture’s warranty on residential work. I went to a Firestone seminar last fall and they were talking about possibly offering a residential warranty in the future but I haven’t heard of that happening yet.

Also those windows look pretty low to the deck. That’s always cause for concern and you’ll want your roofer there before the windows are in.


those curbs should also be a minimum of 8" above roof level at the lowest point of the curb.


yeah ,the window areas will be a problem for venting–FIRE THE ARCHITECT! :mrgreen: