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gottodo1 10-09-2013 08:15 AM

Bathroom Ventilation
SO I was running some new wire through a wall and when I removed the face plate for the bathroom exhaust fan I found out there was no ducting. The way this was installed it uses the 2x4 cavity as the "ducting" and then at the bottom (yes it runs down not up and out the roof) there's dryer vent that connects it to a high CFM exhaust fan. There's alot of dust and stuff in there but there's no mold... This fan also works as a de-humidifier for the whole house until recently when I installed a 2nd exhaust fan downstairs in that bathroom and am using that as a dehumidifier as well. Is this something I should be concerned with? Is there anything I should look for besides rot/mold?

It's one of those BIG high CFM fans or whatever that are big and round and would normally be in the attic... I figure I could probably just run new dryer ducting (or the solid stuff) down to the floor and install the metal angle ducting behind the existing grill... but is that a good idea or even necessary? Any thoughts?

nealtw 10-09-2013 06:43 PM

Your lucky that there is no mold, best is a 6 or 7" duct with as few bends as possible and as short as possible and out the roof is best. you can get oval shaped ducts that fit in a 2x4 wall.

gottodo1 10-10-2013 11:53 AM

Anything else I should look for besides mold? If it's working well as is (aka no mold), how important is it really to run it through the roof... lol I'd rather avoid another project but who knows.

Well, what I've pieced together is that the bathroom used to have a skylight above the bathtub, but they drywalled over it and patched the hole on the roof (almost fell through the roof, that's how I first found this all out), then inside everything for the skylight is still there. Looks like they had a bad mold problem then but when they removed the sky light they must have installed this fan too which is what actually fixed the problem. I was actually thinking of putting the skylight back in since everything's there except for the top dome... but maybe I should put in the ducting through the roof first... It'd be really nice to do an improvement by choice instead of improve something that's wrong for once.

nealtw 10-10-2013 06:07 PM

Going out the side of the house is not all that bad but it important that the moisture dosn't get back to the attic thru the soffit vents. So if it is going out near the attic vent the soffit should be none venting for a few feet right there.

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