We haven't had a working kitchen in a long time. Now that it's structurally rebuilt and drain/vent roughed in, I want to plumb out for the sink/dishwasher and set them up while we wait for cabinets.

I never plumbed a sink from scratch - just replaced a tailpiece/trap. I was looking at P-traps and most are some plastic other than PVC. There is one that's made of PVC that to me seems sturdier, but I have no idea how to connect the P-trap to the sink. It has no threaded collar on the upward-facing end, just a plan PVC pipe hub end - hub x hub.

Is going the PVC route a better, more reliable choice?

If so, how do I attach a tailpiece?

Thanks guys!



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Aplastic that most of the P traps are made of Is polypropylene. It is the most inert plastic and is used to make batteries cuz it is so resistant to acid and degradation. It is unable to be glued because the solvents do not affect it. Kitchen sink drainage materials are made of 1 and 1/2 in polypropylene. Make sure that the rough out drain is low enough so that if you want to put a garbage disposal that the P-trap will be low enough. They're many diagrams about how to connect the drain to the sink. There are several different types of strainers available I recommend one that has a little basket that can be lifted out however it is deeper than the standard strainer but your wife would love it.

before you put that trap on, glue a full size cleanout for future access.

now glue the trap on lining up the "upwards facing" end with the strainer (or disposer outlet).

glue a trap adapter into the trap inlet. this will give you the threaded end with a slip nut that will adapt from sched 40 pipe to a tubular tailpiece. if you don't use a disposer the tailpiece will need a smaller inlet for the dishwasher hose. (called a dishwasher tailpiece)
if you do use a disposer the dishwasher drain hose connects to the small inlet port on the side of the disposer.

Actually I recommend gluing a 1 1/2" (slip) glue x 1 1/2" male adapter on to the stub out and go tubular plastic from there. It is easy to take apart for snaking.

as far as I know a sink tailpiece whether plastic or metal is in tubular size. At the wall the stubout will be PVC SCH-40, so somewhere between you will need to transition from one to the other.

The most common is to put a trap adapter at the wall stubout. Your p-trap will be all tubular. This is also the easiest to install as not only you can slide the p-trap outlet horizontal pipe, you can also rotate the upside down U bend all the way around, the two degrees of freedom makes it very easily to connect and position the p-trap to align with the tailpiece.

But there are some other considerations. First, tubular is smaller in ID, so 1.5" tubular is a smaller size pipe then 1.5" SCH40, therefore the p-trap is also smaller. This could mean easier to get a blockage. If you get a blockage in the pipes behind the wall, a tubular p-trap being all slip joints can be taken apart right at the wall trap adapter for cleaning. However, the trap adapter opening is no longer as big as the SCH40 pipe behind the wall, so it's not full size. If the blockage is inside the p-trap, or if you accidentally drops a diamond wedding ring down the sink, a tubular p-trap can be taken apart easily to clean and retrieve. Second, A SCH40 p-trap has to be glued, and hence the installation has to be very precise, and you still need a trap adapter at the inlet to the U bend, but you get a larger U bend. There is a version of the SCH40 p-trap where the U bend can be removed, those will also give you the ability to roll or swing the U bend into place during installation. However a SCH40 p-trap will not give you access to snaking as the outlet pipe has a 90 that faces down and you can't easily snake it from there even with a removable U bend. This is why Packy suggested a third alternative which is to install a full size cleanout at or near the wall, possibly with a SCH40 wye, then use one end for the CO the other end for the trap adapter to connect to the sink. This will give you the maximum flexibility, you have the ease of install, and you can clean the pipe behind the wall with a full size head without ever having to take the p-trap apart.

Thanks guys for the GREAT advice!

Yeah, I don't want a disposal, but my wife does. Cleanout + disposal height allowance w/a deep under-mount sink is a concern. Is it generally doable?

it is do-able depending on the height of the stup-out.

deep sink with a disposer will want a stub out around 15 inches off the finish floor.