Adding drains for upstairs bath

Old 03-18-02, 08:25 PM
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Question Adding drains for upstairs bath

I want to add a bath to the upstairs in my 1 1/2 story home. I have upstairs access to the wall that contains the cast iron stack -- there is a joint right at floor level.

I'm confident about doing all the plumbing except the drains, mostly because I haven't done that type of work before. I imagine I would have to get enough access to the stack within the upstairs 2x8 floor to cut it and install a "T". I don't have a problem with ripping apart the upstairs since I will be remodeling it anyway. Should I expect cutting the cast iron pipe to be difficult, once I get adequate, tho limited, access to it? Since there;s only about 8 or 9 feet left to the top of the stack, would it make sense to replace the section from the T joint to the roof with PVC?

Does anyone have a good reference that shows how to do this type of project? What would you estimate it would cost, roughly, to get a plumber or handyman service to design and put in the drains, if I did most of the demolition?



Last edited by tright; 03-18-02 at 09:02 PM.
Old 03-19-02, 12:24 PM
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Here is the plumbing and electrical for a typical half/bath, so you would just tie-in the drain and trap for a shower/tub.

You might find the Reader's Digest "The Family Handyman" magazine article that this is from helpful, too, at
I don't know what to tell you about cost estimates. That will vary greatly from place to place.
Good Luck!
Old 03-19-02, 02:49 PM
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Mike has posted a good picture for you to start with. You'll just have to alter things for the exact layout of your bathroom. By all means replace the cast iron with ABS or PVC. It is a lot easier to work with and a lot cheaper. Cut the cast iron with a cast iron pipe cutter. Rent one. Just make sure everything above your cut is WELL supported. That stuff is very heavy!! Tie your new ABS or PVC to the remaining cast using Fernco couplings and fittings. They come in a wide range of styles and sizes.

I won't give you even a guess as to the cost of hiring some or all of this done. Labor rates are too varied. But if you do hire some or all of it done, use ONLY licensed contractors -- not a handyman. And check with your local bldg. dept. to see what permits may be needed. Then get them!
Old 03-31-02, 05:44 PM
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You might be able push the stack up thru the roof enough to tie in a Tee. The stack may have been put together and sealed with lead. You can drill the lead out with a small drill bit, and pry it out with a small screw driver. It'll take 2 people to lift the top section of the stack pipe and put in the Tee. I did this in my top floor, I used a cast iron tee and sealed it back up with stranded lead. It's like lead rope that you pack down with a screwdriver.

I joined the PVC to my cast Tee using oakum and a plumbers plastic type cement. I first pushed in oakum, then the cement, then kept layering it. It is as solid and leak free as you could ever want.

The cement has a putty consistency and hardens like a rock. The oakum is like rope that has been dipped in an oil solution. The stuff lasts a long long time.
Old 03-31-02, 07:57 PM
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[QUOTE]Originally posted by lefty
...Cut the cast iron with a cast iron pipe cutter. Rent one.

I think that is a big part of what I wonder about, not having done this in the past. Will I have enough clearance to use this tool, given that I have to work within the 2x8 upstairs floor joists, which are spaced 16"? If not, is it going to be back (or arm) breaking to try to cut the cast iron with a sawzall?

FYI, I can see a junction in the cast iron that ends about 3 to 4 inches above the upstairs floor. I'd have to insert the T below that.

I'd prefer not to have to disturb the walls or ceilings on the main floor.


Also, thank you to everyone else for the great information!

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