Tying into a basement stack

[Coach606]

Hi everyone:

I'm refinishing my attic and adding a bath with tub, two sinks and a lav. I have archtectural plans and our plan is to run the tub drain and the two sink drains to a vertical lav pipe under the flange. It probably won't be totally vertical and I'll take some caution not to disrupt the flow of each pipe as I do it. This 3" waste line will travel down an existing first floor wall into the mechanicals room of our basement and then need to head towards one of two stacks we have. there are two vent lines running through the roof. I plan to run the wast pipe exposed under the floor joists (they run the opposite way I'm going) to the stack.

My question is about tying into the stack. I've been warned on a few forums not to try it myself and information is scant about how to cut into the stack pipe. It's clearly black cast iron in the attic, but where I'm looking to tie in it's white - maybe galvanized?

Anyway, are there special tools to cut into iron or galvanized dwv pipes (3") here? Or is this a part of the job I should just hire a pro for? Some have commented that I could cause my entire dwv system to collapse if I'm too aggressive with tying into the stack.

Any idea how much it'd cost to get a plumber to tie into the stack once I've run the line?

Many thanks.

 

[Cass]

White would be plastic unless someone painted the pipe. Galvanized is cut with a saw and cast iron with snap cutters which can be rented.

You need to be sure if there is enough room for the new fitting and bands B4 you cut the pipe.

 

[Sponsor]

 

[Coach606]

Cass,

That doesn't sound as complicated or dangerous as other posters have suggested on another board. I may hire someone to handle that part of the job. But in your estimation, is cutting into the stack (I have ready access and it is well supported above) a really hard and dangerous thing for a guy to do?

Again, I was warned by a few plumbers (who promptly offered me their services) that a homeowner shouldn't really do that sort of thing. What's your view? It sounds reasonably simple if you have access, take care, and use the right tool.

 

[johnapril]

I cut into a copper stack (heavy), but first I braced it over and under the cut so the stack wouldn't move or slide once I made the cut.

 

[Rich H]

Of course pros want you to hire them - that's why they are in business. They also want you to believe that work such as this is akin to brain surgery. That's why guys on other boards will direct you to hire a pro for anything more than hooking up a tailpiece.

Cutting into a cast iron DWV is pretty easy - if you have good access to the pipe and room to work, go rent a snap-cutter from your local rental store. Otherwise, you can use an angle grinder(not recommended), or a carbide-grit edged blade in a reciprocating saw (Sawz-all). If you go that route - make SURE it is the grit edge blade and the package states it is for cutting cast iron, otherwise you will learn the meaning of the word frustration. Buy two, just in case you break the first one halfway through. Those blades run 5-8 bucks apiece. A snap cutter is far and away the best option, but you do need some room to be able to hook it to the pipe, ratchet the arm, etc. Snap cutters are kinda heavy and clumsy, but oh so worth it. I rented mine for about 12 bucks for a day - well worth the work it saved me. If the pipe is galvanized (it will look silver, if there is paint on it and you scratch it off, you will see silver) - it can be cut with a reciprocating saw and a bi-metal fine tooth blade. Buy a few extra blades, they don't last forever with galvanized. Anyways, if the pipe is white - good chance it's PVC. You are in LUCK if it is PVC and not cast iron! PVC can be cut with a recipro saw, but in tight quarters sometimes a simple wood hand saw is your best bet. As noted before, make sure your fittings will, well, fit - into the area you are working in. If the pipe is cast iron, go to a local plumbing supply and buy some "riser clamps", should run about 5 bucks apiece - make sure you support the cast iron with these clamps - above the planned cut, and below. These are going to need this to be permanent supports, so plan to connect to framing studs or a similar structurally enabled member. These clamps will have to bear the weight of the stack once you cut a chunk out. If you have CI above and are tying into PVC below, I'd do a bit of investigation to make sure the last person who ripped out the CI to put in that PVC did it properly and supported the CI with riser clamps - if not, better support that pipe before you cut out the PVC!!! I recently ripped out literally the entire bottom half of the cast iron DWV pipe in my house and replumbed it in PVC. It was a 4" cast iron pipe, and I did it myself, no help. Would I recommend this? No, I'm an idiot J/K - anyways, I planned my cuts well and took it out in manageable pieces (5' max length) - plus I'm a pretty experienced DIY'er and an engineer. So, in a large nutshell, I feel that this is a very do-able task if you have some experience, a little skill, and the sense of adventure that comes with completely disabling your house's plumbing system for a period of time. Having an understanding wife helps as well... Good luck!

 

[Coach606]

Thanks for the info and the encouragement...

Many thanks. I'll be sure to follow your advice and support the pipe well as I do this. Luckily, the stack is framed in a soffet with just wood paneling around it. Pop that off and I've got access from all sides and a supporting frame already built.

Again, thanks for all the info and encouragement. Not only will I save some $$$ if I can get this done myself (need the savings, baby #2 about to arrive) but I enjoy the adventure and sense of accomplishment.

The contracter who's building my dormers even offered to let me use his snap cutters. I'll let you know how it goes.

 

[Gary Swart]

Cast iron is mega heavy. I had a stack come crashing down once that I thought I had clamped very securely. Fortunately, both of us were out of harms way when it happened or I wouldn't be writing this.

 

[Master Plumber Mark]

Remember once you are in it , you are in it....

remember the part about it being ..... ....mega heavy.....

usually when I have to snap off a cast iron pipe , I try to

secure the weight somehow above me..... usually with some metal strapping

wrapped arond a tee or branch off above and nailed to the joysts...

just for shits sake.........its just wise to do that.....

maybe I am just a pussey, but I have had one drop on me about 3 inches once........ and life stood still for a moment when that happenned..



then when you snap off the cast, its wise to make a couple of breaks

instead of just two..... cut it three of four times in a three foot area

then knock out the pieces....

Mkae this happen all in one try... make your initial cut more than large


enough to do the job.....

DO NOT nip off another 5 inches of cast off the pipe

afterwards because when the cast snaps off it usually goes flying off like a

bullet doing major damage to life and property.....

have fun....

 

[Cass]

Heed MPMs warning. Once you are in it (make that cut) there is no turning back.

If the stack drops you will have a whole new set of problems.

Many of us have been there.

When snap cutting I try and place a piece of cardboard between me and the cutters to help with flying pieces of cast iron.