drain vent pipe - to pvc and relocating

johnny331

I'm getting a new roof and replacing the cast-iron drain vent pipe with pvc.... Is schedule 40 ok? Standard pvs cement and all?

I plan to reroute it with two 90's to the back side of my roof, just 20 feet run or so. Any problems with that?

What's the standard height/termination of that pipe? Right now there's nothing on top, just an open pipe sticking straight up.

What's the best way to get that old piping out? It's an awful lot of weight. Can it be cut, pulled apart, or smacked with a hammer like my tub needed???

That one Guy

Dont smack it with a hammer You can remove the lead and oakem wich I will not get into or use a special cast iron blade on a sawzall with some cutting oil. This is a pain in the buttox but can be done. I use my rigid close quarter snappers (soil pipe cutters) for this type of stuff. But I dont know if you would want to spend $350.00 on a tool you might not use again.

Tmb9862

I would call Home Depot, Lowes, and any other place that rents tools and try to get a ratchet cutter. It would probably be $30 or so for the day.

Other than that:
You defiantly don't want to get into removing the lead. Tons of work and you would have to pull whole sections out.
A reciprocating saw will work but you're going to use a lot of blades. If you can't find a cutter for the case iron this will be your best bet. Just use some oil, even WD40 will work.
A grinder with a cutoff wheel works well but will sends sparks everywhere and make a mess. Not a good option for indoors.

johnny331

What about diameter? I was going to use 3" (3.5" OD) schedule 40, I measured the cast iron and that's about the same OD, who knows how thick it is... or is there a special pipe I should use?

I plan to cut the pipe off above the slab, and use a rubber boot to convert to pvc. it's a one level ranch, one bathroom right now.

That one Guy

The cast iron and the sch 40 dwv pipe are close in outside diameter. Close enough that the fernco coupling you want to use will say plastic/ci x plastic /ci or something similar. You can use it for both types of pipe.

The cast iron is not very thick just hard. As far as blades go the carbide grit blades do take some time to cut. There are some newer diamond blades from lenox for cast iron pipe that are supposed to cut 3x faster and last 3x longer. They are spendy for 1 blade but they seem to be ok.

I have only used mine once during a recent job in a restaurant on some 2" ci It cut pretty good.

johnny331

I went through two carbide tip saw-zaw blades trying to cut my tub apart, got about 20" done, then got my sledge hammer out and took care of business.

That one Guy

Yep, thats how I remove the old tub and concrete laundry trays.