Kreemoweet
In the Trades
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.
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.