Raising up shower drain and vent for basement remodel
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wwhitney
In the Trades
In the last photo, is the vertical galvanized on the far right the lavatory drain? If so, that can be horizontally wet venting the shower trap as depicted, although the curvature of those old metal fittings leaves a lot to be desired. That horizontal 90 and the black tee should really be a 45 and a wye. So there's something to be said for replacing the black tee and everything upstream (that's currently accessible).
Anyway, with horizontal wet venting, if you want to raise the shower trap, you have to raise the black tee (or its replacement) and everything upstream of it. That is, between the trap, and where the shower trap arm meets the lavatory rain, the trap arm can only fall one pipe diameter, not 5".
Also, does Wisconsin have its own plumbing code, or is it using the UPC? If it's using the UPC, the lavatory drain should be 2", with a 2" dry vent above, since the combined lav and shower drain goes on to apparently wet vent the WC. If you raise the shower trap and the lav fixture drain, and then the combined branch drain needs to drop back down to meet up with the WC, a gradual drop would be best. If you need that to happen more quickly, use two 45s, not two 90s.
Cheers, Wayne
Anyway, with horizontal wet venting, if you want to raise the shower trap, you have to raise the black tee (or its replacement) and everything upstream of it. That is, between the trap, and where the shower trap arm meets the lavatory rain, the trap arm can only fall one pipe diameter, not 5".
Also, does Wisconsin have its own plumbing code, or is it using the UPC? If it's using the UPC, the lavatory drain should be 2", with a 2" dry vent above, since the combined lav and shower drain goes on to apparently wet vent the WC. If you raise the shower trap and the lav fixture drain, and then the combined branch drain needs to drop back down to meet up with the WC, a gradual drop would be best. If you need that to happen more quickly, use two 45s, not two 90s.
Cheers, Wayne
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You can raise that entire line, assuming you also raise the vent at the end for the p-trap to the tub. That should be taken off with a wye and not the existing tee.
At the 4", raising it with 45's would be better. Or the lower 90 would be a long turn 90 and the upper one can be a medium 90.
Normally a flat vent like what you have isn't allowed anymore, so I would at least raise it up some with the wye fitting and then a medium 90 where it turns up. Unless that serves a sink and then a long 90.
At the 4", raising it with 45's would be better. Or the lower 90 would be a long turn 90 and the upper one can be a medium 90.
Normally a flat vent like what you have isn't allowed anymore, so I would at least raise it up some with the wye fitting and then a medium 90 where it turns up. Unless that serves a sink and then a long 90.
No...I think it is just a vent. The upstairs lav is somewhere else
Thanks Terry you totally got what I was asking...appreciate the clear answer.
wwhitney
In the Trades
Ah, so what's the goal here? Just to raise the trap for more headroom?
If so, and if you don't want to raise the galvanized downstream of that black tee, you could do something like the cross-section diagram below. Blue is old (drain and vent) and red is new (except the top of the tub drain should be blue). The vertical tub drain I drew is dashed to show that the other pipes aren't intersecting it, the u-bend and elbow can be swiveled around so that the trap arm is offset from it.
You'd need to drill one joist, that's fine if the hole diameter is less than one third the joist depth and the edges of the holes are at least 2" vertically from the top and bottom of the joist. Also, you might need to jog the new vent along on the joist bay a little to hit the existing vertical vent.
Cheers, Wayne
If so, and if you don't want to raise the galvanized downstream of that black tee, you could do something like the cross-section diagram below. Blue is old (drain and vent) and red is new (except the top of the tub drain should be blue). The vertical tub drain I drew is dashed to show that the other pipes aren't intersecting it, the u-bend and elbow can be swiveled around so that the trap arm is offset from it.
You'd need to drill one joist, that's fine if the hole diameter is less than one third the joist depth and the edges of the holes are at least 2" vertically from the top and bottom of the joist. Also, you might need to jog the new vent along on the joist bay a little to hit the existing vertical vent.
Cheers, Wayne
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Thanks Wayne...the goal is to raise everything (as is) with a drop just before the 4 inch. See the drawing.
I am trying to maximize headroom as much as possible. As Terry commented, that flat vent should be raised so that will go up through a joist...just as you have in the drawing. The remainder would go up tight to the joists ( with 1/4 inch drop thing) with a short vertical drop composed of 45s or long sweep 90s right at the 4 inch.
My main concern was that a short vertical drop wouldn't cause that trap to siphon out. Apparently with that vent I will be ok. I guess ill find out.
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