Doing a major reno and on a whim decided to add a prep sink to the far side of the kitchen.
I am using a 2 inch drain that putts along at 1/4 drop for 18 feet.
I was planning 1 1/2 venting for aprox 22 feet to join the homes secondary stack just before it up sizes from 2 to 3 inch and leaves the house.
My issue is 2x4 joists (old house).
I need to run the vent at 1/4 grade but roof and joists will not allow. The joists are to small to drill. Above is an floored attic space for storage.
At the far end of the ceiling is a small chase created by a 10 inch pony wall in the attic.
I am wondering if I can run uphill to that chase and downhill after it.
The thinking is there will be no trap on either side then. The prep side any thing that got in could go down the 2in drain. The other side it would go down the vent.
If I can do this do I need to change the tees in that vent to wyes?
Edit: after looking again I have the space to run the vent with a constant upward grade till it reenters the stack and will do that
Last edited by trickle; 01-27-2014 at 02:25 PM. Reason: have a new plan