I have a drain pipe that is under the slab in the house , the house was built in 1960, I want to connect another service to run to the apartment just built, the old pipe is inside the slab and I need to connect into it , it's that old Cast metal , and I want to put a T connection so I can have a access to snake out the system, 1 how should I get to the old pipe in the slab , by saw or just drill holes and chip from around it slowly to gain access , and how should the connection of the T be made, welding, soder , of with a boot and sleeve.
Don't know if pre tension concrete was used in the 60s. I have an early 80s house with pre tension concrete slab and its scary to cut into it without knowing where the cables are.
Basement or ground floor slab? What is the existing finish on the concrete? Carpet, tile, exposed concrete??? It makes some difference on how you break the hole and how you repair the hole. How do you know where the pipe is? So you can hope to be over it with your hole. How are you planning to cut the cast iron? Chain cutter (ratcheting or lever handle), gasoline Quickee type saw, Sawzall with a grit edge blade (very slow)? Each choice makes a huge difference on how big the hole needs to be.
The pipe you are after may be as much as 2 feet or more down under the slab. The slab will be about 4" thick. It may have WWF (remesh), rebar, or post tension cables, or nothing. It is very possible to just swing a sledge hammer and break through the floor, once you have a hole it is actually quite easy to keep breaking out the edges of the hole to make it bigger. You really want to have a pretty good idea where the pipe is. IMHO you will be best off planning to tie in plastic fittings using Fernco type connectors. If it is 4" pipe you will be removing a foot or more of the existing pipe (fitting with nipple on each end). You do not weld cast iron pipe, you do not solder cast iron. The very fact that you are asking suggests that maybe you should break the hole and hire a plumber to make any and all connections, you will probably time and money ahead in the long run. Cutting cast iron is not usually for the DIY type.
~~~~~~~~~~~~~~~~~~~~ DanG A live Singing Valentine quartet, a sophisticated and elegant way to say I LOVE YOU! snipped-for-privacy@okchorale.org (local)
Never having even attempted what you're about, my thoughts are truely stray ones.
Me, I'd forget about tapping into a cast iron pipe imbedded in concrete. There's got to be some way to connect to the sewer that's not under or in concrete. Sewer pipe is cheap. So what if it take 100' of plastic pipe to get to somewhere the sewer is surrounded by only dirt?
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