Soil Stack Drainage and wastage systems and plumbing help, advice and answers

[busy]

My house (late 60s) has an internal soil stack (made of a black plastic/composite ? material) approx 5" diameter. There was a small rectangular metal inspection panel which was bolted onto the base of the pipe before it goes underground but this was rotten and has been removed and replaced temporarily with plastic and waterproof tape. (this covered a hole approx 3" x 4" in the pipe) I'm fitting a new kitchen and want to take the opportunity to remove the offending 8" section of the stack and replace with some form of adaptor/connector. Someone advised me to speak to McAlpine regarding a collar with jubilee clips but they don't have anything like that. Screwfix may have something but not sure of best way to proceed Any advice please ? Thanks

[welsh brickie]

marley have a reducer collar AD600 try that.
other than that cut the original soil stack with a grinder I think you will find
its cast iron.

[busy]

Thanks Welsh Brickie (sorry about delay in responding I've been on holiday)

I found the Marley flexible connectors and I think they will do the trick. My next problem is if I remove an 8" section of the stack and replace with a section of 110mm soil pipe using the connectors, will the weight of the soil stack [b]above the cut [/b]start to cause problems/sagging etc ? I'm actually wondering whether I can also a) support the soil stack further up or b) replace the whole stack with 110mm waste pipe.

Thanks in anticipation