alexh
New Member
Hi, would like to convert an upstairs tub to stall shower and need to be sure i have sufficient drain size to downstairs before demo. House is slab so really not practical to change to a 2" vertical drain if its currently a 1&1/2". I can verify by removing baseboard on downstairs closet as i have seen the drain before but forgot to measure - will do ASAP. The vertical drain also shares an upstairs double sink vanity and a downstairs vanity sink.
I have 2 plumbing books and also checked online source and it seems the allowable fixture units is different for every source - a 1&1/2" drain varies from 1 to 3 units for horizontal and 2 to 4 for vertical. Is this because of local differences?
To summarize, my drain units will be stall shower (currently a tub), 2 vanity sinks and an additional vanity sink downstairs. Based on measurements and relative locations, it seems that the tub drain goes directly to the vertical drain pipe, i.e. the tub horizontal is likely not shared with the vanities but of course the vertical will carry all 3. The house has truss between first and second floor. I removed some drywall on garage ceiling but unfortunately cannot see any drain because the tub drain is over a downstairs closet wall.
Also of course will have to redo tub drain to 2" for stall shower.
Thanks
I have 2 plumbing books and also checked online source and it seems the allowable fixture units is different for every source - a 1&1/2" drain varies from 1 to 3 units for horizontal and 2 to 4 for vertical. Is this because of local differences?
To summarize, my drain units will be stall shower (currently a tub), 2 vanity sinks and an additional vanity sink downstairs. Based on measurements and relative locations, it seems that the tub drain goes directly to the vertical drain pipe, i.e. the tub horizontal is likely not shared with the vanities but of course the vertical will carry all 3. The house has truss between first and second floor. I removed some drywall on garage ceiling but unfortunately cannot see any drain because the tub drain is over a downstairs closet wall.
Also of course will have to redo tub drain to 2" for stall shower.
Thanks
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