View Full Version : Help with rough-in and dwv plan

02-12-2007, 06:02 PM
Hi everyone,

I'm planning a new bathroom on what currently is a den at the rear of my 1.5 storey home. I have a good idea of how I am going to drain the waste however the dwv plan is puzzling me. If you look at the sketch I will start at the toilet with a 3" pipe travel west and catch the shower then travel north intercepting the 1.5" vanity drain and then outlet to the stack. The plumbing will all be completely exposed in the laundry room in the basement. My problem is running the vents. I'm not a plumbing expert but understand the principals. The joists all run east and west and therefore what im thinking of doing is running the vents straight up the walls and then cutting into the joists to run through them and eventually tie into the stack. Now there is a bathroom directly above this one so I plan to tie in at a high location on the stack. Does this sound right to anyone? Is there an easier way to do this?


02-12-2007, 10:16 PM
Cutting thru the joists to run a 3" pipe sounds dangerous. You don't want to weaken all the joists. It should be suspended under the floor joists, hangers every 4 ft. Or am I unclear about what you are doing? As for the vents, you could run between the above floor joist to a wall or closet then run up the wall and above the ceiling joists, turn and go to the stack. I'll edit this post with a copy of Terry's drawing....


02-13-2007, 04:57 AM
Talking about plumbing and actually installing it can be two very different things. Until we see how you are actually going to arrange the piping, we cannot tell you if it will be proper or not.

02-13-2007, 04:00 PM
Can I tie into the main stack at a point lower than what the upstairs bathroom ties in. I think this is called a wet vent. I cut wye into the stack so that no waste could enter the vent.

02-13-2007, 05:49 PM
that won't be enough; you have to plan for real venting too.


02-13-2007, 06:06 PM
so basically i'm going to have to go through the roof... thats gonna make my vanity venting a big problem.