I'm adding a shower to a basement 2 piece bathroom. Under the concrete is cast iron drain pipe. Above is ABS vent pipe which I'd like to tie into. Should I use 4" PVC or ABS drain pipe? This house is in Alberta Canada.

Hi Nahtanoj:

I'm thinking that you may be better off to connect into the 2" underground drain line for the sink drain. Here, you can use the vent from the sink as a wetted vent for the shower... could save you tons of labor and a little money as well... ;)

If wet venting isn't allowed in your area then you may actually need to connect into that 4" cast iron, but if you do install a 4"x2" NO HUB CAST IRON WYE fitting into the cast iron drain line. You'll want to use a graphite sawzall blade and cut out 3/4" longer than the wye fitting is from out of the pipe. Then you'll use some 4" no hub clamps to connect into the drain line. The extra 3/4" acommodates the inner ribs on the shielded transition clamps and allows a little for a less than perfect cuts in the pipe!

Off the 2" cast iron branch you'll install a 2" cast iron x 2" plastic shielded transition clamp.. (do not use a 2" no hub clamp here, but OK for 4" cast above)... use the proper shielded clamp (see image) to transition over to ABS pipe and fittings. Stick with the ABS here as it was used and approved in your house before... can't fail with that plan!

Finally, you'll connect the 2" drain over to the shower being sure to install an 1.5" vent within 5 feet of the PTRAP to the shower. You'll connect the 1.5" vent into an 1.5" or larger vent at 42-48" off the finished basement floor.

Back to you...

MARK