Hi, I am adding a new bathroom to my home and have exited the home with a 4" abs sewer drain. I have found the 4" cast iron sewer line heading to city sewer. What fitting do I use to connect to the cast iron. The cast iron pipe is about 1' lower than my new abs when I slope it 1/4"/ft. I would also like to add a clean out at this location. Thanks!

You'll want to install a cast iroin no hub wye fitting. Here, you'll measure the fitting, let's say it is 12" long and then you'll mark out 12.5" to 12.75" on the pipe (see image) and then cut the cast iron drain pipe using a sawzall with a diamond sawzall blade(s), sold by Lennox, or a carbide tipped sawzall blade(s). The extra room is need to account for less than perfect cuts and to accommodate the rib on the clamps you'll use to join the wye fitting to the drain pipe.

The best clamps for this job will be the shielded 4 band, husky clamps (see image). These are only sold at a plumbing supply house. If you clean the pipe real well, install the clamps over the pipe ends and then FLIP the rubbers back on themselves, you should be able to slip the new fitting into place, flip the rubbers back and then slide the clamps into place. Be sure to tighten them hand tight and then wait 20 minutes and return to tighten them a little more for best result.

Let me know if you have more questions...

Mark

Thanks, That was really clear.

I will want to tie into the 4.5" OD CI pipe with a 4.5" ID ABS. My question is do I need that under the bathroom floor? Seems like the 3" abs is plenty. I have a laundry room, double kitchen sink, dishwasher, 2 bath sinks, tub/shower and toilet draining. Is 4" code? Thanks

Sorry, my pics. Above did indicate plastic pipe/fittings (older pics.), but you really should install a new cast iron wye fitting (called a no hub cast iron wye fitting). Some codes will reqquire the toilet to be piped up 4"....most will be fine with 3"... depends on plumbing code in your area. In my area, you would purchase a 4"x3" cast iron no-hub wye fitting and install that into the cast iron main drain.

If you can pick up the toilet with 3" you'll want to install a 3" cast iron x 3" ABS plastic SHIELDED MISSION CLAMP (see image) onto the 3" branch of the 4"x3" no hub cast iron wye to make the transition over to plastic pipe. Otherwise, if 4" is required you'll want to purchase the 4" cast x 4" plastic transition shielded mission clamp.

Purchase the 4 band clamps (1st pic. Above) for the to install the cast iron fitting into the main drain... purchase the shielded mission clamps (see below) for the transition to plastic pipe.

That will bring the job up to plumbing code standards... ;)

Mark

PS: The no hub cast iron fitting is actually easier to install than an ABS fitting because with ABS you'll need to cut, prime and cement in pieces of pipe to the fitting... with cast, you just drop the fitting into place.