Fitting new waste pipe to Soil stack.

29 Aug 2004
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United Kingdom
We are going to install a new shower in our bathroom. This will involve fitting a new waste pipe to the internal Soil stack. This would be below where the WC discharges into the Soil stack. Can we do this? what is the simplist way of going about it


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You can use a strap on boss fitting which involves cutting a 50mm hole in your stack, strap the boss fitting on, fitting a 40mm bung in and then running your 40 mm waste pipe into it. This must be 200mm below your toilet connection as this is a no go area.
Quite straightforward if your stack is plastic but if it is cast iron you will have to drill small holes in a circle to make the hole.
Not done a cast iron one yet but have read it is fun :evil:
Once you've cut the hole, make sure you wash your hands before picking your nose :LOL:
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BAHCO said:
Not done a cast iron one yet but have read it is fun :evil:
i did a cast iron one once and used a saddle with some epoxy to hold it on...
you mark the size of the hole with a pencil and put dab marks around the circumference
then you use a very small drill to perforate not letting the holes touch each other but as close as you can
then you very carefully chisel out the inner part by cutting the little links between the holes
wear brown trousers and do the job in time to get down to the pub to cry or celebrate..
A decent holesaw will go through cast iron quite easily (mine were 63mm holes I believe), but I've yet to see a plastic strap-on boss on a CI pipe that isn't leaking. That includes a couple I've tried, usung plenty of silicone. Haven't tried Araldite though!

There are better solutions, DESIGNED to go on a CI soil pipe. Any good merchant...

If you have a CI stack don't be tempted to change it to a plastic one - they're much noisier!
Administrative c rap (excuse pun) connections to stack pipes need building conrtol inspections.

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