installing WC in top floor - question regarding soil pipe

19 Oct 2014
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Tyne and Wear
United Kingdom

I'm looking at the possibilities of building a shower and toilet room into part of a large attic bedroom, and hopefully connecting the WC to the existing internal soil stack/vent. There is a 110mm soil stack running vertically through the house serving the middle floor WC only, venting out through the roof of the house. Does anyone know if it is possible to connect a second WC to this existing soil stack?

I've drawn a diagram of the plan

Many thanks
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I think it depends on the WC outlet size.

Search Building Reg 2010 and read up on section H1.
No problem, but check carefully if there is (or you plan to) connect anything at ground floor level. Sometimes pressure created from falling waste from an upper floor appliance can cause problem at ground floor level.
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As Hugh says - your diagram shows an easy long radius bend @ the bottom of the stack - If you have one like this you're OK . If it's a knuckle you might get problems, but a vent system could be arranged if you really had to ;)
Thanks for all the advice so far - glad to know it looks possible. It is a long radius bend.

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