Move waste line up or down

[Csukraw]

So my new vanity lines up exactly with where the waste line comes out of the wall. If I were to cut the vanity, the shelf would lose all structural integrity so I am forced to move the line in the wall. I basically need to raise it 2 inches. My question is do I need to move the entire sanitary tree? If I do, I’ll need to drill new holes through both studs which is not ideal. Am I able to install 45 degree angles inside the wall to raise the pipe in the wall? Or will that go against code and cause potential syphoning? See photo below for proposed 45 degree angles. Thanks for any advice!

 

[wwhitney]

No vertical jogs between the sanitary tee and the trap, that way lies siphoning. So if you want to raise the height at which the trap arms emerge from the wall, you need to raise the sanitary tee. [In some jurisdictions you could use an air admittance valve in the vanity and then have a downstream vertical jog, but California doesn't allow those.]

Is dropping the vanity down a possibility, by shortening the legs or toe kick?

Cheers< Wayne

 

[Sponsor]

 

[Terry]

You have to raise the fixture cross in the wall. You can't use fittings to raise the traps without causing them to siphon the traps dry and make your bathroom the smelliest bathroom on the block.

 

[Csukraw]

Ok I figured as much. So my only option is to raise the tree. So cutting another hole in each stud a couple inches up isn’t a structural issue?

lowering the vanity isn’t an option either.

 

[Terry]

Just drill more holes and move it all up.

 

[wwhitney]

Code wise, I don't see any discussion in R602.6 about minimum distance between holes. So you could drill your new holes touching or overlapping your old holes. If it's not a bearing wall, then I wouldn't worry further, just drill a 2" hole that lines up across the width with the hole below. [If you use a hole saw, you could pop the cutout back into the old hole, although that's of no structural value].

If it is a bearing wall, then once you exceed 40% of the stud width, you need to either double the stud or use a stud shoe. Not sure if the stud shoe would be compromised by the extra hole. You could check out a Simpson HSS2-SDS1.5 and see if all the fasteners would miss your hole. I'd be inclined to cut out as much drywall height as reasonable and then scab on a reinforcement block with structural screws, and use a double stud shoe.

Cheers, Wayne

 

[Csukraw]

Very helpful, thanks guys. Doesn’t seem to be a structural wall so I think I’m good.