I am in the middle of a complete remodeling and upgrade of my 80 YO,5' x 9' bathroom. Toilet runs ditect into the 4" vent stack and will remain in the same place. New sink is circuit vented back to the stack and will be moved approx 15" further away from the stack but extending the 2" circuit vent should keep this working fine. The issue is what to do about the new Tub/Shower drain and venting. If I use a left draining unit it puts the drain in perfect alignment on the same wall as the sink and toilet and I could easily extend the vent circuit to include the tub. Full distance drain to vent would be approx 5'. What does not work as well is that to do the rough plumbing and have access to it later on I would have to tear into the lath and plaster wall in the adjacent bedroom not only creating a mess but some cosmetic issues as well. If I go to a right drain unit I will have complete and easy plumbing access since that area was the old attic entrance and will be easily accesible and modified to suit this purpose. The issue for the drain and venting is this, It would now move the tub drain approx. 9' from the main stack and 5' from the closest sink curcuit branch.

1) do I need to vent the tub for this short distance (5') if I use 2" drain after the 1.5" trap?

2) if so, Can I run this along the outside wall behind the shower surround, add a 90* turn back to the sink vent circuit?

3) and if yes that, wouldn't that weaken the outside wall considerably by drilling 2.5" holes for the PVC vent pipe to pass through?

Thanks in advance for your expert help.

Quote:

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Originally Posted by nervous

I am in the middle of a complete remodeling and upgrade of my 80 YO,5' x 9' bathroom. Toilet runs ditect into the 4" vent stack and will remain in the same place. New sink is circuit vented back to the stack and will be moved approx 15" further away from the stack but extending the 2" circuit vent should keep this working fine. The issue is what to do about the new Tub/Shower drain and venting. If I use a left draining unit it puts the drain in perfect alignment on the same wall as the sink and toilet and I could easily extend the vent circuit to include the tub. Full distance drain to vent would be approx 5'. What does not work as well is that to do the rough plumbing and have access to it later on I would have to tear into the lath and plaster wall in the adjacent bedroom not only creating a mess but some cosmetic issues as well. If I go to a right drain unit I will have complete and easy plumbing access since that area was the old attic entrance and will be easily accesible and modified to suit this purpose. The issue for the drain and venting is this, It would now move the tub drain approx. 9' from the main stack and 5' from the closest sink curcuit branch.

1) do I need to vent the tub for this short distance (5') if I use 2" drain after the 1.5" trap?

2) if so, Can I run this along the outside wall behind the shower surround, add a 90* turn back to the sink vent circuit?

3) and if yes that, wouldn't that weaken the outside wall considerably by drilling 2.5" holes for the PVC vent pipe to pass through?

Thanks in advance for your expert help.

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I presume you are referring to a loop vent when you say circuit vent. Where you have two pipes, the bottom pipe used for drainage and the top pipe connected at the end of the drain line and looped back into the main vent.

1) do I need to vent the tub for this short distance (5') if I use 2" drain after the 1.5" trap?

Where would you be draining the tub in relation to the circuit vent line? If into the drain pipe of the looped vent you're within code. The one thing you must remember is that every fixture that has a trap must be vented.

2) if so, Can I run this along the outside wall behind the shower surround, add a 90* turn back to the sink vent circuit?
If you're referring to the vent , yes but if you're referring to the drain line would that not put it over the 5' from trap to vent rule?


3) and if yes that, wouldn't that weaken the outside wall considerably by drilling 2.5" holes for the PVC vent pipe to pass through?
We make our holes 2 9/16 for 2" PVC. If your referring to 2 X 4" studs yes,(our code states no more then 33% of a stud shall be cut or holed.) if 2 X6 or 8" studs, no.

The reply:

Q: I presume you are referring to a loop vent when you say circuit vent.
Where you have two pipes, the bottom pipe used for drainage and the top pipe
connected at the end of the drain line and looped back into the main vent.

A: Yes, this exactly what we are talking about.

1) do I need to vent the tub for this short distance (5') if I use 2" drain
after the 1.5" trap?

Q: Where would you be draining the tub in relation to the circuit vent
line? If into the drain pipe of the looped vent you're within code. The
one thing you must remember is that every fixture that has a trap
must be vented.

A: It would be no further than 5' from the nearest loop of venting at the
vanity. I'll have 1.5" tub/shower trap into 2" drain, sloping to the main 4"
cast iron stack. If I were to move the vanity vent loop over another
16"-20" closer to the tun/shower it would make the tub/shower run less than
4'.

2) if so, Can I run this along the outside wall behind the shower
surround, add a 90* turn back to the sink vent circuit?

Q: If you're referring to the vent , yes but if you're referring to the
drain line would that not put it over the 5' from trap to vent rule?

A: it is the vent but since they are 2x4 this is now not practical.

Thanks,

Herb.