Lav / kitchen sink trap size?

[Jwray]

Is a lav trap always 1 1/4" and a kitchen sink trap 1 1/2"?

I have several lavs and a kitchen sink to install. I'm planning to use 1 1/2" drains for a single lav a 2" drain for a double lav and a 2" drain for my kitchen sink w/dishwasher & garbage disposal. The vents will either be 1 1/2" or 2" (2" drains will use a 2x2x1 1/2 sani-T to connect to trap arm). 1 1/4" lav traps will use a 1 1/4x1 1/2 trap adapter.

I realize some of this may be a bit of overkill (i.e. 2" drains/vents), but I figure I'll probably never have to worry about a clog.

Does this look OK?

Thanks,

Joel

 

[hj]

traps

Kitchens are always 1 1/2", lavs can be either 1 1/4" or 1 1/2". If the plumbing was installed properly, there should be no "double lavs with a 2" trap".

 

[Sponsor]

 

[Jwray]

Clarification

Sorry, let me clarify the double lavs.

Each lav will have its own 1 1/4 or 1 1/2 trap and trap arm which will hit a trap adapter at the wall and empty into a 1 1/2" drain. These drains will run horizontally (w/slope) to a double fixture fitting (2x2x1 1/2x1 1/2) which has 2" vertical drain and vent.

Does that sound correct?

Also, I just this weekend saw a 1 1/2 trap and trap arm that will connect to a 1 1/4" tail piece with a reducing washer. I think my lavs only have room for a 1 1/4" pop up/tail piece assembly. Would the reducing washer be an acceptable way to adapt to a 1 1/2" trap and trap arm? I realize I could just use a 1 1/2 x 1 1/4 trap adapter, but I'd like to have a larger trap to prevent problems with hair clogs, etc.

Thanks,

Joel

 

[hj]

trap

If I am reading your posting properly, then that is the way it is done most of the time in this area. Namely, a 1 1/2" trap with a reducing washer on the riser. I hope you have a cleanout in the riser beneath the double fixture fitting, because if you do not and the underfloor line becomes obstructed you may/will not be able to snake it.

 

[Jwray]

Reducing washer & Cleanout question

HJ thanks for the cleanout tip.

Is this also necessary on a standard single fixture or can you snake through the sani-t with the trap /trap arm removed?

Also when you say "reducing washer on the riser" you are talking about where the trap meets the riser extending down from the sink drain hole itself correct? So from the sink drain hole to the riser is 1 1/4" then from the trap through the trap arm and into the trap adapter is 1 1/2", correct?

Thanks,

Joel