converting an external drain to an internal drain

15 Dec 2008
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United Kingdom
I am about to extend my kitchen. Currently the drain that collects the waste from the sink, washing machine e.t.c is directly outside the kitchen underneath the window.
When I do the extension this drain will therefore be inside the new kitchen. I want to keep the drain in the same position as the new kitchen is to have a peninsular unit with the sink basically being in the same location as the old sink.
What I am unsure about is what to use to convert the old external clay hopper to a satisfactory internal drain with no smells entering the house.
For building control purposes I have to either have a cctv survey, or expose the current drains so I was thinking of breaking into the drain run just outside the new extension, fitting a collar and then running new plastic fittings up into the kitchen, but I am unsure as to the type of hopper to use internally, and whether this is the best way to go about it. Any ideas would be great.
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fit a gulley trap and a straight peice of pipe bringing it to sub slab level.
you can then fit a 110mm spigot into the end of this pipe with a 40mm pipe adaptor within it.



IMHO that's asking for trouble unless proper access is provided for cleaning.

You're better off doing away with the gully completely and relying on the traps at the appliances to prevent foul air ingress. Any sort of trap is liable to become blocked with grease from a kitchen sink.

IMHO that's asking for trouble unless proper access is provided for cleaning.

my thoughts entirely mike.

this was suggested on a recent job of mine (by b.c.), though access was still possible via an access plate. only trouble was a kitchen was fitted on top of the access plate leaving only a 6" void in which to try and bend your arm around! :rolleyes:
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Many thanks noseall, mike

So what are we saying? do away with a trap and put a sweeping rest bend on and vertical pipe up to slab level and then either the spigot or some kind of adaptor to seal the waste pipe and accept the 40mm waste from the kitchen?

I guess whatever I do I will have to run by b.c. anyway

Thanks again
That's what I would do. If the wastes are sealed you only need one trap so why introduce problems?


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