Kitchen Drain under Window

[samx3]

Hoping for some guidance here. I'm renovating the kitchen in a 100 year old house. The sink is shifting about 4' to the right and will now be under a window. I'm not certain that the old plumbing was even done properly but I want to get it right this time.

1. Does entire waste line need to be 2"? The old one was 1.5".
2. Does cleanout get installed directly below double sanitary tee or off the back of the basement horizontal span?
3. Should I consider AAV above double tee and abandon span over to old vent? I suppose I'd have to add cap to cover top of vent outside.
4. Is there a maximum number of ells in drain or vent line?

 

[John Gayewski]

Generally you'd run a 2" pipe up through the floor beside the window. A 1.5" arm would travel horizontally under the window and the sink would drain into that. The vent can be 1.5"and would continue vertically beside the window and connect to the vent system above the counter top in the wall. Your double sink would be hooked up inside of the cabinet work slip joint tubing and fittings. Cleanout would either be on the 2"pipe in the wall or in the basement/crawl space.

 

[Sponsor]

 

[John Gayewski]

If your allowed to use an aav you'd run 2" into the bottom of the cabinet with a 2x1.5x1.5 tee and the 1.5 inch sections would get a trap adapter and the vent on would go on the top section. Cleanout would go below the tee, but you really don't need one with the slip joint fittings as they come apart in the event of a clog.

 

[Reach4]

1. A two-bowl sink often only needs one trap.
2. You may be able to feed that trap over to under the left part of the window. Need a picture? I don't know how long a 1.5 or 2 inch trap arm is allowed to be in WI.

3. If you will have a disposal, putting that under the right bowl may be best.

 

[Reach4]

1. A two-bowl sink often only needs one trap.
2. You may be able to feed that trap over to under the left part of the window. Need a picture? I don't know how long a 1.5 or 2 inch trap arm is allowed to be in WI.

 

[Jeff H Young]

inspectors really dont like vents below flood level so having the main beside widow opening , normally rather than drill studs king studs etc I run trap arm close to wall cant do this on side with dish washer plan now not later

 

[samx3]

Thanks everyone for the advice. I see the wisdom of the drain pipe to the left of the window rather than directly under the window. I subsequently researched the flood level rule and see that the horizontal bend needs to be 6" above top of sink or 42", whichever is greater. The single trap makes sense too.

My biggest problem is the short horizontal run over to the vent stack. Because it's above the sink height, I have to bury it in the wall. Yet code doesn't allow me to drill a big enough hole in the 2x4 studs to fit the 1.5" vent pipe. I believe the only solution would be to double up the studs. While this isn't completely impossible in my situation, it will certainly present significant difficulty. Any other options?

A final clarification. Because it's a kitchen, does code require that the drain pipe itself be 2" for the entire distance from left of the sink trap all the way to the main stack?

 

[Jeff H Young]

typically 1 1/2 trap arm size 2 inch verticle drain, 1 1/2" vent so you will use a 2x1 1/2x1 1/2 santee. take note the trap arm can be outside the wall as long as the dish washer isnt on left side