Home & Garden

bathroom fan into attic

  • Last Updated:
  • Jun 8th, 2021 2:45 pm
[OP]
Sr. Member
Mar 3, 2009
503 posts
35 upvotes

bathroom fan into attic

I was thinking about putting in a fan in the bathroom, exhaust into the attic.

But I`m wondering about sending humid air into the attic - doesn`t seem like a good idea.

It would probably be better to connect to one of the vents in the roof.

Does anyone think it would be ok to just vent into the attic, without connecting to a roof vent? Could the attic handle a bit of moist air?
13 replies
Member
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Apr 14, 2009
237 posts
116 upvotes
Vaughan
You will be creating a mold factory, it needs to be vented out of the attic.
Deal Expert
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Jun 12, 2007
16403 posts
5140 upvotes
London
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$$$$$ mold remediation = remove / replace shingles + remove/ replace roof decking plywood + remove replace attic insulation + seal wood trusses

Bathroom fan needs it's own dedicated / sealable vent thru the roof
Last edited by l69norm on Jun 8th, 2021 10:50 am, edited 2 times in total.
Deal Addict
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Oct 4, 2001
1404 posts
71 upvotes
how about out the wall
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Deal Addict
Sep 13, 2003
1283 posts
112 upvotes
definitely a bad idea to vent to attic.
im not an expert but i think based on my prior search about venting, out to the wall may not be a great idea if your vent is close to your soffits as the moisture can creep back into the attic. best is to vent out the roof, you're saving your family and wallet from any unneeded financial expenses for repairs
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Mar 30, 2004
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Edmonton
Your fan has to vent to the outside. Through the roof or through a wall, doesn’t matter. Do not use an existing vent unless there is nothing else attached. Not hard to put a new vent in a roof.
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Dec 11, 2003
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Toronto
I saw one of those reno shows on HGTV and the contractor said bathroom fans have to be vented outside. That's all I know about bathroom fans. I'm not sure if it has to be horizontal to the ground or just outside at the closest spot on the roof though.

If you don't know stuff like this shouldn't you hire somebody to do this for you (instead of guessing)?
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Deal Addict
Sep 22, 2009
2020 posts
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Markham
Always vent outside or you risk mold inside your attic.
Deal Fanatic
Jan 15, 2004
6592 posts
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Must not vent into the attic. Definitely will have mold issue. Connect it all the way to the roof and install a vent. You can also have the vent comes out on the side depending on your house. My basement bathroom vents to the side of the house.
Deal Addict
Apr 18, 2005
2611 posts
992 upvotes
Mississauga
hammer wrote: how about out the wall
If its the second floor , roof is the new normal. I had mine venting into the soffit.. and when I did my home inspection the inspector made a note of it. When we did the bathroom reno, I got it redone into a roof vent.. Contractor said it was just flexible dryer hose that was just sitting on the soffit loosely held onto the fan.. he just touched it and it all came off...
Deal Addict
Sep 22, 2009
2020 posts
670 upvotes
Markham
You will need an insulated hose. You don't want condensation collecting inside the hose.
Member
Sep 29, 2015
277 posts
81 upvotes
Winnipeg, MB
fred999 wrote: I was thinking about putting in a fan in the bathroom, exhaust into the attic.

But I`m wondering about sending humid air into the attic - doesn`t seem like a good idea.

It would probably be better to connect to one of the vents in the roof.

Does anyone think it would be ok to just vent into the attic, without connecting to a roof vent? Could the attic handle a bit of moist air?
Do you have a HRV or ERV that is ducted to the bathroom?
[OP]
Sr. Member
Mar 3, 2009
503 posts
35 upvotes
Thanks everyone - out the roof will be the way to go... then I`ll need to trust the guy to seal the vent properly to prevent leaks
Penalty Box
Jun 24, 2015
4954 posts
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i had a dryer vent that came loose and was not just venting hot air in the basement ceilings but also left a huge messy pile of lint everywhere, in every nook and cranny of my basement ceiling took for ever to clean
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