I have a crawlspace house, and would be easier fit for me to put my trap further down the horizontal run (in between the floor joists) before it ties into the main run under the house. In other words, drop straight down through baseplate of wall, (36-39") then 90 into the horizontal 2" run, then 90 sweep into the main 3" line.

also, does a 2" washer line need to be vented? Mine's currently not vented itself, but there is 1 roof vent tied in elsewhere off the main 3" run. its that sufficient venting for all, or should i look at maybe installing a studor vent somewhere in-line on the 2" horizontal run before it gets back to 3" main? Thanks for any help ! -paul

Hi Paul...

No need for the PTRAP under the floor... can run pipe above the floor, install a 2" sanitary tee fitting to pick up the PTRAP and then install a studor vent...all above the floor.

Connect into the 3" main using a 3"x2" wye.

Install a 2" cleanout where accesible.

You definitely need a studor vent (at minimum) on a washing machine drain... see images.

Questions? Let me know, OK?

Mark

Mark -

Thanks for the help! And from what I've read, studor goes after the trap, not before it... right? Next question is on the height of the studor. This is a 2'-3' limited height crawlspace. My option for adding the studor will have to either be just a few inches sticking out of a T, in the horizontal run, headed back to the 3-2 wye... or else at the end with the 3' main (about 14' away / horizontal run) when I make a couple feet vertical drop to get to the wye, could put in a T instead, where I was going to 90 down to the wye. This will allow for 1-1.5' height for studor.
(this is at the end of house where it goes underground, so the main is almost at ground-level where wye will be)

Is there any minimum vertical height requirements for studor coming off a horizontal after the trap? (in my crawlspace situation)

Also... can you explain "sanitary" tee? I'm a dyi amateur, trying to tackle myself to save a buck. Thanks, mark. -paul

Never mind about the minimum vertical question, I see the 4" minimum in one of the drawings. Thanks

Hi Paul...

All this is supposed to be ABOVE THE FLOOR... ;) The standpipe and the vent should be higher than the flood level rim of the washing machine, OK?

See image below... let me know if you have questions. The SANITARY TEE FITTING is indicated below.



Back to you...

Mark

No problem making the standpipe above top of washer (using a wallbox)
But trap and vent will need to be below floor, no other options. Laundry is in the interior of the house, and can't vent to roof. Will this be OK?

Thanks mark. No problem making the standpipe above top of washer (using a wallbox)
But trap and vent will need to be below floor, no other options. Laundry is in the interior of the house, and can't vent to roof. Will this be OK?

Also... do I have to put the trap directly at the bottom of the vertical drop from standpipe, or can I 90 elbow at bottom of standpipe, then put the trap along the horizontal run headed back to the 3-2 wye?

Plumbing code says that the trap and vent need to be above the floor. All should fit in the wall above the floor or you can install outside the wall behind the washing machine.

Install the studor vent higher than the wall box (if putting in wall) and use an access panel to access the studor vent if needed in the future. The trap should fit in the wall no problem.

Here, it is not common practice to install the trap and vent below a floor... not "readily accessible" in terms of the trap and vent.

If you want you can get a dual outlet wall box and install the standpipe to one outlet and the studor vent to the other outlet... ;)

If you still decide to install the trap and vent under the floor you definitely cannot install it inline as you suggested... must be at the base of the standpipe or you would be creating a RUNNING TRAP... again, illegal in terms of plumbing code.

Good luck!

Mark