We are new here but hoping you might offer some advice.
We are remodeling the upstairs bath in our 1920's home. All fixtures are stack-vented (no other vents anyplace in the house.) The tub and toilet are both well within the distance limits for stack venting, so no problems there although we are replacing all the old lead drains with new. The sink currently has an S-trap into the floor, which runs to the stack about 7 feet away.
We would like to improve this situation without adding a new vent up though the roof or reventing back to the stack through a wall, which would entail ripping apart the plaster/lathe walls, not within the scope of this project. We also really need to avoid messing with the soil stack (which re-venting would entail) as it is old and we don't want to have to replace it, a much larger project!
We are considering whether it may be beneficial to make a sort of "chicago loop" type thing like people do in kitchen islands, wherein the new sink's P-trap goes back into the wall and then includes a loop in the wall, as shown, where the top elbow is higher than the water level, and where the drain line back to the stack in increased to 2".
I've drawn a very crude sketch here; not showing pipe pitch or anything but you get the idea.
Would this work? Any other ideas? Our town uses the International Plumbing Code rules.
Thanks for any input anybody has!
Stacey PS Hmm, I have added an attachment but it does not seem to be showing in preview. I will try submitting and see what happens.
The valve can be vented in the attic, just 6" above the insulation and doesn't have to go out the roof according to the code book I've been reading (2006.)