I have a Cast iron soil stack 3" going from the basement to the roof. No turns angles,nothing but a straight stack. 2nd floor has a tub, toilet and sink. 1st has a kitchen sink. Since the bell of the cast iron is so large, builders framed around it. I really need the space this framing takes up. I was considering duplicating the whole stack/drain in 3" PVC. Is this within the scope of a fairly handy guy? Or call in the pro? I'd hate to say it looks easy,which it does, but that's when problems begin! Thanks, Gordon.
Too much for a DIY'er?
- Thread starter Gordon
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Jadnashua
Retired Defense Industry Engineer xxx
I'm not a pro, but I think you would be okay. First, though, I'd double check the codes to see if the 3" still meets code for the number and type of fixtures that you have. Actually changing it out shouldn't be that hard, but passing code because you made a change, it has to be up to current standards. Maybe you are, maybe you aren't. Check first. Connecting from the pvc to the cast iron is fairly easy, cutting the old stuff out can be a pain without experience, but is doable.
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Three inch plastic fittings take up less space than the the cast iron hubs, but not all that much. The outside of a 3" fitting is still going to be 4 1/16"
You must need the room pretty bad to go to that much trouble.
How much space will you be gaining?
The amount of work to change that is considerable.
You must need the room pretty bad to go to that much trouble.
How much space will you be gaining?
The amount of work to change that is considerable.
Last edited:
Gary Swart
In the Trades
Too much for a DIYer?
Looks can be deceiving. It isn't technically so tough, but cast is heavier than sin and since the stack is standing on end, it can difficult and dangerous to take down. When I install a bathroom in my basement, I had to redo the drain and vent stack. No one was killed or injured when the clamp that was supposed to hold the stack while pieces were sliced off didn't hold and 15 feet of 4" cast came crashing down, but it was just plain blind luck! Once the cast is out of the way, then installing ABS or PVC is pretty straight forward. A no hub connector will make the transition easy from cast to plastic, and obviously ABS or PVC is much easier and safer to handle.
Looks can be deceiving. It isn't technically so tough, but cast is heavier than sin and since the stack is standing on end, it can difficult and dangerous to take down. When I install a bathroom in my basement, I had to redo the drain and vent stack. No one was killed or injured when the clamp that was supposed to hold the stack while pieces were sliced off didn't hold and 15 feet of 4" cast came crashing down, but it was just plain blind luck! Once the cast is out of the way, then installing ABS or PVC is pretty straight forward. A no hub connector will make the transition easy from cast to plastic, and obviously ABS or PVC is much easier and safer to handle.
Jimbo
Plumber
Maybe I am too pessimistic. The vertical stack is one think. How much work are you willing to tackle to gain access to the stack connections on the first, second floors ? You have to "disconnect" the stack from the waste runs and make provisions to reconnect these.
It does seem to be alot of work to change out the stack and all waste connections. By doing so I gain about 5 sq ft in the kitchen which is quite abit in a 9 x 13 room. None of the existing plumbing is within the walls except for the stack. The toilet on the second floor needs to be moved away from the tub because from the toilet to tub there is only 6 inches of clearance. Not much room for wide bottoms!! In addition, all of the drywall/plaster has been removed so I have complete access to every fitting. I know the cast is heavy, I was thinking I'd remove it from the top down, then rebuild from the bottom up sinking the pipe as deep in the wall as possible. I know I'll have to shim the wall out but perhaps only 3/4 inch to enclose the piping. Several repairs have been made to the drains and stack but they are not correctly done. Gobs of epoxy spread around fittings, radiator hose from a car, just a mess. Any you folks live in Maryland? Will pay for good help!!! Happy Holidays and thanks for the inputs, Gordon
LonnythePlumber
Plumber, Contractor, Attorney
3" Cast
I didn't realize there was 3" cast used for a soil stack. In my area we will replace a 4" stack with 3" plastic to save space but it's a semi-major thing including replacing trap arms. It is best to check your connections to make sure the idea will work before starting demo. I'm glad Gary mentioned the cast iron dropping as an alert and reminder to us all.
Plan well. This is probably more than a one day job.
I didn't realize there was 3" cast used for a soil stack. In my area we will replace a 4" stack with 3" plastic to save space but it's a semi-major thing including replacing trap arms. It is best to check your connections to make sure the idea will work before starting demo. I'm glad Gary mentioned the cast iron dropping as an alert and reminder to us all.
Plan well. This is probably more than a one day job.
Deb
I think that you should make sure that the venting and drainage is correct in the first place before you duplicate it--I take it you are going to move the toilet (?). Your home is apparently older and the plumbing may well be a long ways from current codes.
I also have seen some near disasters with cast not secured, so be careful. It is also tough to cut, so you may want to rent some cutters made for cast.
This is a major undertaking for a novice. I would be real surprised if this did not take several 3-4 days.
Deb
The Pipewench
I think that you should make sure that the venting and drainage is correct in the first place before you duplicate it--I take it you are going to move the toilet (?). Your home is apparently older and the plumbing may well be a long ways from current codes.
I also have seen some near disasters with cast not secured, so be careful. It is also tough to cut, so you may want to rent some cutters made for cast.
This is a major undertaking for a novice. I would be real surprised if this did not take several 3-4 days.
Deb
The Pipewench
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