Drain location for kitchen sink rough-in

[JMingrone]

Good info.

Thanks again,

Jay

[JMingrone]

Well, did the right thing and sawed out the old galvanized fitting in the bathroom and replaced everything below with 1-1/2" plastic, tied it all together with rubber couplings on each end. Came out nice, so I buttoned up the wall, satisfied the job is now right. Kitchen is next, using 2" plastic which'll give me a proper wall drain and eliminate the "S" trap through the floor i was originally planning.

Thanks to all for the guidance.

Unrelated question:

When gluing the plastic together, I was surprised to find that after inserting the pieces together (pipe to elbow in this case), the parts wanted to spring back apart. I actually had to squeeze them together for about 10 seconds to get them to stay. I've done plastic before and don't remember this happening before. Have others experienced this?

-Jay

[jadnashua]

Unrelated question:

When gluing the plastic together, I was surprised to find that after inserting the pieces together (pipe to elbow in this case), the parts wanted to spring back apart. I actually had to squeeze them together for about 10 seconds to get them to stay. I've done plastic before and don't remember this happening before. Have others experienced this?

-Jay

This is entirely normal. If you tried to push the pipe into the socket of a fitting without any cement in it (i.e., dry), you'd find it is really hard to do - the socket is tapered. The glue liquifies the plastic in the socket and the pipe, when the solvent evaporates, it welds the pieces together. But, it's still tapered, and the soft plastic acts like a spring to push it back out until the cement gets stiff enough to hold it. Once the solvent fully evaporates, you can't reasonably get them apart as they have become 'one' piece of plastic, not two.

[JMingrone]

Thanks Jim. Thought I picked up the wrong cement or something...

[JMingrone]

OK, tomorrow i'll be cutting out the old santee. Kremo- just wanted to make sure i understand what you said about waiting to install the trap adaptor til later. First of all, the trap adapter is the piece that has the compression ring that squeezes onto trap pipe, right? If so, the one I bought is real short and glues directly to the santee. Installed that way (the way was planning before re-reading your suggestion), the compression washer is right up close to the wall. I think what you suggested is to NOT glue that adaptor in now and wait til later where I have the option of, what, putting a length of pipe, THEN the adaptor? Sounds like an excellent idea, so wanted to make sure that's what you were getting at.

Also, one final check before I start cutting. The santee now exits 8 inches to left of the sink centerline, 11.5" above the finished floor. I can't change the 8" offset (unless it's a REAL problem) but I can change the height. I'll be putting a double bowl sink in and the disposer will be on the right. Is 16" a good number? Is it better to err on the low side or high side?

What did you mean by "putting a bend in the trap arm"?

Thanks

[kreemoweet]

Trap adapters come with both hub and spigot fittings to attach them to the drainage piping. The advantage of stubbing out the drain from the wall (with a length of
1 1/2 pipe) is that you can later adapt the location of the trap adapter to work well with whatever sinks or equipment eventually gets installed. This could sometimes
involve inserting bends and other short lengths of pipe. The entire horizontal assembly of pipe and fittings that emerges from the santee in the wall, and attaches to
the J-bend of the trap is known as the "trap arm", and not just the piece that comes with the trap that you buy in the store.

In your case, it sounds like you will need at the very least a short section of pipe attached to the santee to put the trap adapter where you can attach the slip joint nut and
perhaps an escutcheon to cover the hole. Experienced plumbers in this forum have put forward the guesses of 15 and 16 inches AFF as good heights for a drain with disposal
installed. Note that unless you actually calculate or mock up with the actual appliances, it is indeed a GUESS. Being on the low side is always preferrable, as the difference can
be accomodated with the use of a tailpiece extension or similar device, whereas a drain that is too high can only be corrected by opening the wall and reworking the drain
piping there.

[JMingrone]

That's a good recommendation, so I'll hold off til the end before putting the adaptor on.

Thanks again,

Jay

[JMingrone]

Well, the cutout of the old 2" galvanized stuff and replacement with PVC went well.

Question regarding supply shutoffs:

If you have easy access from below (basement in my case) can the hot and cold shutoffs for the kitchen sink be located there instead of inside the sinkbase? Also, does the dishwasher have to have a separate shutoff? I'd be happy either way, just wondering what the code was.

Thanks,

Jay

[JMingrone]

If you have easy access from below (basement in my case) can the hot and cold shutoffs for a kitchen sink be located there instead of inside the sinkbase? Also, does the dishwasher have to have a separate shutoff? I'd be happy either way, just wondering what the code was.

Thanks,

Jay

[jadnashua]

Most people will be happier with the shutoffs near the sink. If you need to replace the DW, do you want to be without water at the sink for who knows how long? Give it a separate shutoff. They do make some dual shutoffs so you don't need a T and to branch to a completely separate valve body if you prefer.

Not sure on the code, but for convenience, in the cabinet.

[JMingrone]

OK, getting ready to put supply stubs to sink. Shutoffs will go in the sinkbase.

Question on the DW supply: can I simply "T" off the hot supply line inside the sinkbase (below the sink shutoff), put a shutoff there for the DW and run some kind of flex line through the wall of the sinkbase to the DW? That would be the easiest way for me. If so, what kind of fitting should go on the output side of the new DW shutoff to adapt to the flex line?

Thanks

[Terry]

A standard shutoff with 3/8" compression for the dishwasher water supply, and yes this can tee off from the same 1/2" as the kitchen faucet.
Normally we tee that off in the wall.
If you have a closed system, then code requires a water hammer arrestor for the dishwasher hot.
A stainless braided supply works fine there, with a 3/8" MIP by 3/8 comp. 90 el at the dishwasher.

[JMingrone]

Thanks for the quick reply Terry. I got the torch running...

My supply stubs come up through the floor. Would you put the T below the floor to make a separate stub off the hot supply or T off the vertical stub for the sink inside the base cabinet, or does it even matter?

Where would the water hammer arrester go? Is that something you can buy?

Thanks, Jay