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+-- Thread: Venting exhaust fan air when replacing a roof (/showthread.php?tid=7362135)
Venting exhaust fan air when replacing a roof - jihhwood - 04-08-2021
My wife and I are about to hire a contractor to replace the original roof on our 19 year-old home. The home-builder vented two bathroom exhaust fans into the soffit. We have learned that such an arrangement does not meet code requirements. Our reading has led us to one solution that does meet code requirements: to vent each fan to the outdoors through the roof, using an appropriate hood to prevent rain from entering the attic. (We do not know whether the exhaust fans in question have a damper. The roofing contractor has not mentioned the need for a damper.) I’m looking for guidance: Specifically, are my expectations of the roofing contractor realistic? Is there more I should be asking (or expecting) of my roofer? Thanks.
RE: Venting exhaust fan air when replacing a roof - srv52761 - 04-08-2021
You do not give a location, but here in Iowa I am always concerned with condensation.
Make sure they insulate the straight, smooth tube (not corrugated flex) then insulate some more.
Above the roof it will be colder than inside the house for a few months a year. Having a vent whose interior is smooth will help dispel the moist air before it condenses.
While in Europe I saw a fitting that looked like a can, placed about half way up the exhaust pipe. Completely under the insulation, it collected the condensate and allowed it to drain under the eaves. Haven't seen one in the US.
A vent called Roberts Bath Vent looks interesting, but I have no experience.
RE: Venting exhaust fan air when replacing a roof - MstrCarpenter - 04-08-2021
venting thru a wall is always my first choice. I'd rather un 10-15' horizontally before opting for my second choice; vent out the soffit. I use 4" sched. 20 pitched towards the exterior and the pipe always extends out through the siding. Putting a hole in the roof, in my opinion, should be only as a last resort.
RE: Venting exhaust fan air when replacing a roof - Splinter Puller - 04-09-2021
(04-08-2021, 09:44 PM)MstrCarpenter Wrote: venting thru a wall is always my first choice. I'd rather un 10-15' horizontally before opting for my second choice; vent out the soffit. I use 4" sched. 20 pitched towards the exterior and the pipe always extends out through the siding. Putting a hole in the roof, in my opinion, should be only as a last resort.
Can't you install a soffit discharge vent that meets code?
RE: Venting exhaust fan air when replacing a roof - TDKPE - 04-09-2021
(04-09-2021, 07:37 AM)Splinter Puller Wrote: Can't you install a soffit discharge vent that meets code?
Like maybe this one?
Everbilt 4 in. to 6 in. Soffit Exhaust Vent-SEVHD - The Home Depot
I didn't know soffit vents were against code, unless they just left the end of the hose in the vented soffit area. I don't see why a real vent would be a code problem.
RE: Venting exhaust fan air when replacing a roof - Snipe Hunter - 04-09-2021
(04-09-2021, 09:23 AM)TDKPE Wrote: Like maybe this one?
Everbilt 4 in. to 6 in. Soffit Exhaust Vent-SEVHD - The Home Depot
I didn't know soffit vents were against code, unless they just left the end of the hose in the vented soffit area. I don't see why a real vent would be a code problem.
Soffit vents are fine. The OP said venting "into" the soffit, not "through". Can't vent into a soffit, can vent through the soffit.
The flapper is to keep birds from nesting in the duct. Not sure if the flapper is code but it is "Best Practice".
RE: Venting exhaust fan air when replacing a roof - jihhwood - 04-09-2021
Excellent information and a helpful link. Thanks very much.