Mathew Johnston
New Member
Hi all,
I'm refinishing a small main washroom in and old house. Second floor corner room. Joists are 2x8. I'm having trouble reconciling all of the code requirements given constraints imposed by the room.
Referring to the below diagram (top down view of DWV)... The red section has too significant a slope at length to meet the trap arm requirements (I will explain why), and I'm considering the addition of the green section for venting. I don't know whether this horizontal section would violate the rule against horizontal vent runs below the floodline+6" limit.
The reason I have this problem is as follows:
The line from main stack out to the "sink and up to vent" runs perpendicular to the floor joists. To penetrate as close to code (middle of joist) as possible (6' = 1.5" slope for 1.5" pipe), the sanitary tee coming off of the stack is positioned somewhat low relative to the 8" joist space.
On the other hand, the shower's p-trap outlet must be positioned near the top of the joist space in order for it to fit in there. I've tried to maintain 3" pipe for as long as possible towards the shower drain to maximize the trap arm distance allowance, but just can't reach it without flooding the vent.
I have to split off horizontally to reach an exterior wall cavity where I can run the vent up to join back to the stack. Is this allowed? I hope so because I don't see any other option.
Thanks!
I'm refinishing a small main washroom in and old house. Second floor corner room. Joists are 2x8. I'm having trouble reconciling all of the code requirements given constraints imposed by the room.
Referring to the below diagram (top down view of DWV)... The red section has too significant a slope at length to meet the trap arm requirements (I will explain why), and I'm considering the addition of the green section for venting. I don't know whether this horizontal section would violate the rule against horizontal vent runs below the floodline+6" limit.
The reason I have this problem is as follows:
The line from main stack out to the "sink and up to vent" runs perpendicular to the floor joists. To penetrate as close to code (middle of joist) as possible (6' = 1.5" slope for 1.5" pipe), the sanitary tee coming off of the stack is positioned somewhat low relative to the 8" joist space.
On the other hand, the shower's p-trap outlet must be positioned near the top of the joist space in order for it to fit in there. I've tried to maintain 3" pipe for as long as possible towards the shower drain to maximize the trap arm distance allowance, but just can't reach it without flooding the vent.
I have to split off horizontally to reach an exterior wall cavity where I can run the vent up to join back to the stack. Is this allowed? I hope so because I don't see any other option.
Thanks!
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