# attach bathroom fan vent to dryer vent



## hohadcr (Jul 25, 2009)

i am adding 2 bath fans and a dryer vent to the 1st floor of a 3plex.

1. can i combine the 3 vents into a main vent?

2. as i cant reach the main vent to the roof, can i guide the vent to one side of the building and get to open air from there?

thank you


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## beenthere (Oct 11, 2008)

No, can't combine them.

Why can't you reach the main vent to the roof.


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## hohadcr (Jul 25, 2009)

this is an old house; 2nd floor & 3rd floor share the main stack -- 2nd floor using wet venting.

1st floor was formerly modified and dont connect to upper floor and right now has no vent at all.


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## beenthere (Oct 11, 2008)

Ok.

Can't combine them though.


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## stubits (Dec 30, 2008)

I tend to ask more questions here than I answer, but something doesn't sound quite right.

HOHADCR- Your most recent post sounds like you are talking about plumbing vents, either PVC or cast iron. This sort of venting is totally different from venting exhaust/dryer fans. Maybe I am understanding you wrong, but please don't try to connect an exhaust fan to your plumbing vent stack, that would be dangerous, for sure!


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## hohadcr (Jul 25, 2009)

Thanks, stubis.

I do have question about plumbing vents too and posted them in plumbing section.

I got it, no combining plumbing vent with other ventilation.

Question, why cant I combine bathroom vent w/ dryer vent?


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## stubits (Dec 30, 2008)

I default to "because beenthere says so," but that is too simplistic.

First, I am sure it is a code issue that prohibits it, but even more so, you need to be able to clean out your dryer ductwork and if there are all sorts of wye's and fittings, that is going to be awfully difficult. Also, the dampers included on the bathroom exhausts are weak, so you'll likely end up with lint and moist air from the dryer being blown into your bathroom. By the same token you will end up with smells and moisture from the bathroom making their way to the dryer. Also, with all the moisture from two bathrooms AND a dryer, I think it would just make a total mess of the lint.

I have found that if it sounds like the easy way out, it is probabally wrong.


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## beenthere (Oct 11, 2008)

IMC. Section 504.1 Dryer exhaust systems shall be independent of all other systems.


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## AndrewF (Dec 29, 2008)

Don't do it.

The previous owners of my house had this bright idea to do the same thing.

What ended up happening was the exhaust fan became full of lint and a firehazard as now the dry lint was all around the bulb in the fixture.

It also caused moist air and "dust" to re-enter the bathroom....even though there is a one way vent door on the exhaust fan.


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## Gary in WA (Mar 11, 2009)

Where is Waldo behind door #4: http://www.hcpdc.com/pdf/Dryer Vent Requirements.pdf

Be safe, Gary


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