Re: Venting lavatory sinks
Posted by Phil on March 20, 2004 at 23:18:41:
In response to Re: Venting lavatory sinks
: : I am remodelling my bathroom and the position of the vanity basins is to be moved. I thought I could just drain the new basins into the same drain that the shower and bath go into but looking around your site it seems that this is more complex. I had never heard of venting until I checked out your site! Can someone advise me on how I should do this?

: : The bathroom is on the top floor. At present the bath tub drain runs about 10' sloped horizontally, the shower drain runs about 5' - they both are 1 1/2" ABS pipes which join in a Y into a 2" drain which has a 2" vent pipe to the roof which eventually T's into a 3" pipe out through the roof (many other 2" and 3" pipes T into this as well). The existing vanity basins have their own vent pipe but I can't get to this because of the joists.

: : On the same wall that the new basins are to be installed there is another 3" vent pipe but I am not sure what it is venting as there is no bathroom beneath this.

: : So my questions:
: : 1. Is it ok to run the new vanities into the same drain as the bath and shower?
: : 2. Do I need a new vent?
: : 3. Can I T into another vent pipe or do I have to run a new pipe to the attic and T into the 3"? Cutting the holes for a new pipe will be very difficult so I would like to avoid this.
: : 4. If I have to run a new vent should it be 2"?

: : Hope you can help,
: : Phil

: It sounds to me like the tub and shower are not vented. The shower should have a 2" trap and drain. You need to know what the other pipes are for before you can cut a drainage line into them. I would recommend calling a plumber and having him or her look at your individual system and advise you as to what you can and cannot do. This will be money well spent. It doesn't sound as if there is a straightforward answer to your questions based on the information we have..."many other 2 and 3" pipes tee into this also".
: Deb
: The Pipewench

Thanks - the shower and tub do vent but I guess I don't know whether the vent is to code or not. Please see my reply to e-plumber.

The other vent pipes are for the other bathrooms - they are actually 1-1/2" and 2" - in total 4 vents join in the attic before going through the roof in a 3" pipe. (Another 4 vents join to a different 3" pipe going through the roof - I thought they were connected but they are not).

If you think something could be wrong with this setup I'll get a plumber to check it but we've been in the house for 3 years and there have been no problems - maybe with your help I can keep it that way.

Thanks again,

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