Hello,
I have a home built in the 50's. A frame home with a 2 to 3 foot crawl space under wood flooring. I want to enlarge the kitchen into the ajacent bathroom and move the bathroom into an ajacent bedroom. The cast iron drain or vent is currently between the kitchen and bathroom. I am removing the entire current bathroom floor due to prior water damage. I would like to do as much of the work myself and have some remodel experience and most of the tools. The present kitchen plumbing should be fine I just need to run new drain lines for a shower, tub and sink. I have run new copper under the house so I can do the supply lines just want the drain to work properly. Any help is much appreciated.

You going to leave the toilet in the kitchen?

That would be convenient howerver I am moving it about 10 feet into the room next to it which is now a bedroom along with a new tub and walk in shower.

Extending, (I presume extending) that sewer line and relocating the stack is going to be the difficult part. After that drainage of the tub and sink will be not problem. Suggest you draw schetches of what you have now and what you want to do. Tom (Speedball1) and Mark (Massplumber) will be along shortly and advise you. You will definitely owe them a Christmass card when you are through.

Start with the toilet, attach toilet vent, continue to first 3"x2" Y for tub, then 3"x2" Y for sink. Attach new sewer with old. Place vents accordingly.

Sink vents directly from 2" x 1 1/2" San tee, toilet and tub has few options for venting. You can combine all vents above anti-siphon level ( about 48" hight above floor ) in one vent. Continue to the attic with one vent. In the attic, either combine with old vents or cut new hole through roof, terminate about 12" above roof, install flashing.

Bump

Johnstwogirls:

You will need to rent a ratchet snap cutter (see picture below) to cut into the cast iron pipe and transition over to PVC pipe. Here, you place the snap cutter onto the pipe, tighten the knob and then using the lever handle... *SNAP*... the cast iron pipe clean/square. If breaks unsquare or crushes the pipe then you will need to make a new cut using a sawzall and cast iron cutting blade (Lennox diamond balde works great! ).

Be careful of the cast iron stack/vent work at the bathroom area as cast is quite heavy and if trying to remove a vent stack you will need to remove from the TOP DOWN.. ok?

Then to transition over to the PVC pipe you need to purchase a shielded transition clamp as in my first clamp picture (cast iron x plastic pipe clamp)... or, can also use the 4 banded clamp as in the next clamp picture but you will also need a NOHUB x PVC adapter here (this is how I do it... have 4 bands to tighten not just two)... all of this is available at a local PLUMBING SUPPLY HOUSE.

Then depending on your bathroom layout and where you are from you would run pvc to a wye fitting with a full size cleanout in the end of wye and then branch over 3" pipe to the toilet. Install a 3"x2" wye fitting just before the toilet elbow and pipe 2" to the lavatory and tub and effectively WET VENT the toilet and the tub using the 2" lavatory vent pipe (must connect full size 2" back into the vent system at around 48" off the floor (or higher, or in attic)).. see last picture for example.

The picture does not show that all fittings off the drain line should be WYE fittings, but it does show how a WET VENT works for your bathroom... The idea is that you use only 1 fixture at at time and with the lavatory vent size increased to 2" the lavatory vent acts as vent for all fixtures when each is used individually. Of course, if you want to try to wash your hair and flush the toilet at the same time... this system may not work well for you... ;)

Check with local codes enforcement in your area to see if this is an approved plumbing design in your area... ;) If it isn't then you may need to run an individual vent for each fixture as suggested at Milo's post.

Let us know if you have any more questions...

Good luck...

MARK