Double vanity from single

[nc8861]

We had a single sink vanity in place. Now we're remodeling and will be getting a 60" double sink vanity. Unfortunately I cannot use the stubs/drain that are existing, because the vanity has cabinet/drawer vertical supports that are right where the current supplies stub out.

Can someone tell me how to go about resolving this? I can sweat pipes and know about the fittings for the drain, and the tees, elbows, etc. My main concern is the layout & design - I really don't want to mess with the main drain line or the main vent stack - I want to tie into those. With the drain line - I'll have to drill large holes through several studs to pass the ABS drain through to both sinks. What is code restriction on size of holes to drill through studs? And how many holes can I drill and how far vertically between each hole? I'll have to drill holes for hot, cold, and drain.

 

[nc8861]

I should also note that this is on an exterior wall. The supplies are in that wall, and the current drain line is drilled through a 2x4 stud to get over to the vent.

 

[Sponsor]

 

[Sjsmithjr]

Are you going to notch or bore? I'll assume notch since I can't see you passing drain pipe of any length through existing stud walls.

25% notch is allowed for an exterior or bearing wall. Since a 7/8" notch won't do you much good, you'll need to use a stud shoe (Simpson HSS/SS series or equivalent) to reinforce studs notched for the drain pipe.

 

[Southern Man]

We had a single sink vanity in place. Now we're remodeling and will be getting a 60" double sink vanity. Unfortunately I cannot use the stubs/drain that are existing, because the vanity has cabinet/drawer vertical supports that are right where the current supplies stub out.

Can someone tell me how to go about resolving this? I can sweat pipes and know about the fittings for the drain, and the tees, elbows, etc. My main concern is the layout & design - I really don't want to mess with the main drain line or the main vent stack - I want to tie into those. With the drain line - I'll have to drill large holes through several studs to pass the ABS drain through to both sinks. What is code restriction on size of holes to drill through studs? And how many holes can I drill and how far vertically between each hole? I'll have to drill holes for hot, cold, and drain.

With pre-made cabinets you can usually hack out big chucks of the sides near the back to make room for the drain line. That wy you don't mess with the wall at all. There's usually a lot of room behind the drawers as well- or you can always shorten a drawer. If you can do that the supply should be easy.

I'm not sure of the Code requirements for plumbing two vanity drains together with a common vent but I've done it before and it worked fine.

 

[hj]

sinks

I'm not sure of the Code requirements for plumbing two vanity drains together with a common vent but I've done it before and it worked fine.

By that I assume you used the "if it fits and works it is okay" method of plumbing. A plumber will make the necessary revisions to the drain system. To do it correctly may mean reworking the drain riser, but that is seldom an issue to a competent worker.