Should new toilet require cast iron soil pipe cut/replacement with plastic

Hi,

We recently got a new toilet fitted which was badly connected to the existing cast iron soil pipe coming into the bathroom. Basically the guys installing left the existing connector (probably wrong word!) and added a new one to it and sealed with good old silicone! Strangely enough this started to leak and got progressively worse.

Now they are back looking at it and tell me that the cast iron soil pipe coming into the bathroom will need to be replaced with a plastic pipe so that the correct connector can be purchased (they are not going to charge for this). So they are planning on cutting into the elbow of the cast iron pipe outside, replacing with plastic - cementing the joint and then connecting plastic to plastic internally.

I am guessing this is all about the standard width of the metal pipe not being the same as the more modern plastic connectors - but I would have guessed there is an adapter or something like that to go from 9cm to 8cm?

Probably a vague question but I am mainly wondering on what people think about the approach - it is correct or should I get them searching for a better adapter/connector?

You can get a flange with a slightly longer 4" pipe out of it (that goes into the metal pipe)and this might solve your problem. You will still need to use silicone to seal it but it did the trick for me when I had difficulty connecting to a frayed lead pipe.

My description mightn't be the best but a plumbing supplies will know what you want if you let him know what it's for.

Hi Pee,

Just FYI - I managed to pickup something that looks like it will do the job nicely. It is a 3.5inch to 4 inch extender - apparently 3.5inch is the standard width of the cast iron pipes so that goes in one end and then the new plastic connectors are 4 inch and go in the other end. All look like they will fit snugly and not require silicone - doing it tomorrow so will let you know in case your silicone wears.