View Full Version : Running DWV through framing in an old house

12-07-2008, 08:08 PM
Hello all,

I have an older (1914) house where a back porch was framed in and converted at some point to a half bath. I am now wanting to convert that half bath to full.

I have a boatload of questions, but the current one has to do with running DWV through the framing. The half bath conversion was very half-@ss, with almost all the supply and DWV lines run on the surface, and covered with soffits. I want to get as much of that run through the floor and walls as possible.

At the bottom of the walls, I have 2x10s turned up on edge, like so:


The wall shown in the picture will have a pedestal sink on the left and a toilet on the right.

Will it be OK to notch this out for the DWV lines, or will I need to raise the floor and let the lines run over the edge of the 2x10s?

If it's OK to notch them out, what would be the easiest way to make the cut? Hole saw?

Moving to the top of that same wall, I have this:


Again, is there any way to notch this out without damaging the structural integrity, or will I need to drop the ceiling and let the vent run over the framing?


12-08-2008, 06:35 AM
It would be nice if we knew the orientation of the two pictures. You cannot do anything to that beam unless it is completely supported underneath by a bearing wall which would also have support under it.

12-08-2008, 11:51 AM
Thanks hj.

Hopefully these pix will help. Bottom of the wall in question:


The right side is sitting on the foundation (again, this was a porch at one point). The left side is sitting on this:


And one of the supply lines froze. Yay.

Top of the wall in question:


12-10-2008, 08:38 PM
I solved my own problem by working around it.

The wall opposite this wall doesn't have the joists in place - it has empty space where a DWV could happily run. So I'm instead going to swap the fixtures across the room: put a clawfoot tub in the space pictured and let the vent lines come out on a wall that also has space. Put the toilet and sink on the opposite wall where the joists aren't in the way. It's an easy compromise to make.

12-11-2008, 04:40 PM
Make sure you get that J box out of the wall so it is not concealed.

12-11-2008, 05:07 PM
Are any of these outside walls?

01-01-2009, 09:29 PM
3 out of 4 are exterior walls.