Connecting to Cast Iron Soil Pipe

[Dustyy]

Hello Everyone,
I am currently in process of installing an understairs toilet and am at the point where I need to connect in to the existing cast iron vertical soil pipe which runs, conveniently, right out side the wall where the new toilet waste will exit the wall.
I have done a search on the forum and there are a number of posts about this topic where advice is that a section of pipe is removed and then an adaptor fitted to enable the connection. I would like to just drill a suitable hole into the pipe to connect into. Is there an available connection on the market to facilitate this type of connection? Bit like a strap on boss that you can get for plastic soil pipes.
The existing pipe work is in good condition but I am a bit concerned about the weight of the stack putting a lot of strain on the existing brackets if I were to cut a section of the pipe out and then fit a rubber adaptor. I assume a significant amount of support for the stack is provided by its vertical integrity. If I was able to simply cut a hole then most of this support would remain?
I am quite happy to be patient with it if that whats required and I am not bothered by the possible smell....got a peg for the nose to hand!
Cheers.

 

[45yearsagasman]

I would like to just drill a suitable hole into the pipe to connect into.

I don't think thats possible and afaik a section has to be removed and correct adaptors and fittings must be used.

 

[Dustyy]

Thanks for your reply.
Do you know what adapters and connectors are required?
Thanks again.

 

[Dan Robinson]

Two slip couplings and a branch.

 

[WedgeAntillesRed2]

There's no way now or even in the future that you could drill into a 4" c.i. stack to accommodate a 4" branch. Physics just wont let it. Even if you could drilling a c.i. pipe with that size hole would be a nightmare from inside the building!
Bite the bullet and except your going to have to remove a section of stack. Use a couple of adapters. Fit one adapter on the end of a 4" branch. Mark outside on the stack where the lower cut needs to be. Cut the stack about a foot above where the branch will be. Use 4" plastic soil pipe to join into top of branch and top adapter. Your very lucky to have rubber slip couplings to do this these days. Use plenty of silicon lube.
As for the integrity of the stack, try climbing it like a cat burgger! If it moves don't shake it lol

I usually use an angle-grinder to cut the 4" c.i. Using a hacksaw would be time consuming to say the least. I think you need a license to use an angle grinder in u.k these days though

Hope springs eternal

 

[Terrywookfit]

It would probably be quicker and easier to replace the stack with plastic.

 

[WedgeAntillesRed2]

It would probably be quicker and easier to replace the stack with plastic.

He might not have ladders, or suffer from vertigo!

 

[JimCrow]

.

Or a timesaver cast iron branch and couplings



.

 

[Toptrader]

Hello, I think this might help. Some useful information on the subject here: https://www.bbsbuilding.co.uk/how-to-connect-a-plastic-pipe-to-a-cast-iron-soil-stack/

 

[HERTS P&D]

10 years too late!

Andy

 

[Bod ...]

10 years too late!

Andy

That's why a time saver was needed

 

[Nige F]

TARDIS more like