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JW40 · Nov 18, 2009, 08:03 AM

Hi everyone. I am new here so thanks in advance.

When I bought my house the garage was plumbed for a bathroom. I am having trouble identifing 2 pipes and what their uses were intended for.

I know one is the sink but not sure which one ( I think this is the 2" pipe in the photo). The other is 2 1/2" same as the shower and toilet vents and about 15-16" off the back wall. I have attached a photo and labeled the things I am sure of. Please take a look and see if anyone may be able to help me positively identify the other 2 in question.

Thank you guys very much for any help you can provide.

massplumber2008 · Nov 18, 2009, 08:19 AM

Hi JW...

Here's what I think all this is... read below.

JW40 · Nov 18, 2009, 08:27 AM

Thank you for the very fast reply and diagram. OK I will install cleanouts on all vents as you recommend.

Would it be possible for me to install the vanity at the 2" sink drain on the front wall and vent as suggested then also install a large stainless wall mount sink on the 2 1/2" on the back wall for washing dishes and such? If so, how would I vent the sink on the back wall since the drain is 15-16" out in to the room?

Thanks again very much.

massplumber2008 · Nov 18, 2009, 08:30 AM

You can do it... The vent would just stub out of the wall at about 28" off the finish floor and connect onto the pipe after it picked up the sink waste.

You would run an 1.5" vent up the wall and connect into all the vents in the ceiling.

All vents pitch back toward the drain

All pipes get hung every 3-4 feet

All fittings for the vents are inverted.

MARK

JW40 · Nov 18, 2009, 08:36 AM

OK I understood most. I am confused on these 2

All pipes get hung every 3-4 feet

All fittings for the vents are inverted.

Thanks again mark!

massplumber2008 · Nov 18, 2009, 08:50 AM

Hang the vent pipes in the ceiling every 3 or 4 feet using strap hangers or plastic j hooks (sold at all plumbing and home improvement stores). In the wall, you want to clip the pipes firmly using galvanized clips.

When I say inverted fittings it means that fittings are installed backwards for vents... so water from the roof vent (rain water or condensation) will drain back by gravity to the drain pipe... will actually FLOW back naturally. If you installed them regular, like in waste pipe, water would fight to flow back toward drain... see image.

MARK

JW40 · Nov 18, 2009, 08:55 AM

OK, great! Thanks so much for all the info.

One last question on the back wall sink. Since the drain is out in the floor area after I mount the sink and install the p-trap am I correct in thinking that the vent will be just below the p-trap going back to the wall then up to the ceiling?

massplumber2008 · Nov 18, 2009, 09:03 AM

Nope...

A wall mount sink may be tough here... not impossible, but tough! The vent must come off the top of the trap... see image. If you need to stick to wall mout sink then take your trap off at say 15" off the floor and then install longer tailpiece out of the strainer. That should leave enough room to install the 2 90s to bring you back into the wall...

You may need to use 2 -45s to offset the DRAIN pipe back toward the wall before picking up the ptrap and vent... not shown in drawing.

MARK

JW40 · Nov 18, 2009, 09:09 AM

OK that makes perfect since. Thanks again for all of your help Mark.

massplumber2008 · Nov 18, 2009, 09:15 AM

That's why we're here!

MARK