Can I tap the drain here?

Old 03-28-16, 07:03 AM
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Can I tap the drain here?

I have doing a attached garage addition with a second floor. On the second floor I want to put a bathroom right next to my master bath. When I opened the wall under the master bath, I can see my supply lines (going to the shower and to the toilet).

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However, I only can see the drain for the toilet in the master bath. Can I replace the elbow with a T and plumb my new bathroom to it. I don't really want to cut anymore holes in the floor joist nor do I want to open up the drywall in the main part of the house. Thoughts?
Old 03-28-16, 10:13 AM
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You can not use a T or sanitary T fitting. You need to use a wye (Y) fitting or a sanitary combo fitting. Measure your space and the fittings as you could have an elevation problem because the wye and 1/8 bend fitting needed on top are taller than the elbow you are replacing.

Old 03-28-16, 10:19 AM
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I believe you can use that 3" pipe as a drain for your new bath. It looks like you'll have some difficulty cutting off that elbow and having enough pipe available to attach your wye. Also, I'm not sure you have enough height for a combo wye to connect to your existing toilet...

Other things to consider is whether you'll have enough height to get to your new toilet and other drains. Also you'll need new venting for your new bathroom.

Other pros will be around with more details and ideas.

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