I'm renovating our basement and I have a waste stack with a roughed in sink fixture trap arm. We are putting a wetbar on the other side of this wall probably around 2' to the left of this waste stack through the double stud (this is a load bearing wall). Please see the below picture:

waste stack with fixture trap arm

Here's a picture of the wetbar on the other side (waste stack painted white for some reason):



  1. I don't believe there is a problem drilling through these studs am I correct? I believe code says up to 60%? I live in BC, can anyone confirm this? pipe size is 1 1/2"

  2. Can I direct vent into this waste stack? If so, I will will have to have to either go above or below the existing T fitting, but my problem is I have a deep sink, so I'll probably have to go below the existing T fitting. What do you guys think?

  3. Do I need a cleanout on my wet bar fixture? or can the removable p trap be a sufficient cleanout?

thanks so much!



For those that come across this, this is what I ended up doing:

enter image description here

1 Answer 1

  1. I believe that you are correct. Here is an article that discuss notching and drilling of studs: http://www.familyhandyman.com/walls/drilling-holes-notching-and-boring-holes-in-wood-studs/view-all

Load Bearing Walls:

Holes may not exceed 40 percent of the stud’s width (1-3/8 in. maximum in 2x4s; 2-1/4 in. maximum in 2x6s). The exception: Holes up to 60 percent of the stud’s width may be drilled through no more than two consecutive “doubled-up” studs.

While this article is not specific to BC, I believe that it is the same.

Note the limitation of only passing through two doubled-up studs. In you case, to get the new sink to about 2' over from the existing sanitary, you will have to pass through two studs. The first stud is already doubled-up but the second one is not and will need to be doubled-up. That will be as far as you can go.

  1. Yes, can connect the drain of the bar sink into the vertical drain with the top portion acting as a vent for both sinks. The connection can be either above or below the existing as required to fit your new sink.

  2. Most inspectors accept removable p-traps in lieu of cleanouts and is a common practice.

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