I have a flat TPO roof that will be replaced in a few weeks, so I need to figure out what I should do to vent two bathrooms and have it ready before the roofers arrive so that it can be flashed and sealed properly. The vent really isnt the problem. The part that needs to be correct is adding a 3-4" pitch pocket in the foot properly, so it doesn't leak.
Once the pipe is properly installed any vent cap can be installed. The other issue with flat roofs is the vent needs to be high enough to account for the flat roof flooding and holding water. The way our house is constructed the only option to vent the bathroom outside is through a modified bitumen flat roof.
Types Of Roof Vents For Bathroom Fans - Design Talk
Is there a specific type of vent. My interpretation is that you are not allowed to place a fan vent termination on a flat roof. It also indicates that on sloped roof the termination should be elevated 18".
There seems to be a lack of what is an acceptable venting configuration for a bath fan when you are forced to go through a flat roof. I am starting a garage conversion and part of it will be a bathroom with shower. approx 4 sqm floor space.
Venting Bathroom Fan Thru Roof - Artcomcrea
All 4 sides of the new bathroom will lead to other rooms so I think it is best to install an extraction fan which vents up and out of the flat roof. It is possible to vent a bathroom fan through a flat roof, but this is not always the best option. The risk for leaks and subsequent problems is high, especially when done as a DIY job.
Venting through the wall or hiring a professional to install the vent is preferable. Roof vent hood details The best exhaust fan venting is through smooth, rigid ducts with taped joints and screwed to a special vent hood. Although this isn't always possible in attic crawl spaces, you should always insulate the duct to prevent condensation problems.
Bathroom Extractor Fan Flat Roof Vents - Artcomcrea
I've had a chronic problem with a leaking bathroom vent during storms (like this one). I thought I fixed it last month when I found some exposed flashing around the vent on the roof. Apparently not.
I think now that the vent shroud was intended for a pitched, not flat roof. It appears that this. Fit the Ducting, Fan, and Vent Feed the ducting in from the bathroom side until it protrudes through the hole in the roof.
Fasten the fan in place in the bathroom. On the roof, cut the ducting to the correct length and fit it to the structure of the vent. Install a Flat Roof Vent in 5 Steps Determine the Center Point When you are running your ventilation pipe through the attic drill a hole in.
I also thought maybe there was something about the vent height and clearance related to the slope of the roof? I suggested an alternative which was to run the vent through the exterior wall, and he said that would be fine, but I doubt that the wall cavity allows for more space for insulation vs the roof.
