40mm shower waste to external 110mm waste

4 Jan 2012
Reaction score
United Kingdom
Hi guys
We had to drill our 40mm shower waste outside to run down to connect it to the main 110mm underground waste. Currently the 40mm pipe is just sticking out the wall - do I / can I just run the 40mm pipe down the wall and connect it to the 110mm soil stack underground (with an inspection chamber or something)?

Or is there a better way to go about it?

Sponsored Links
How far down is it? Would a gulley be of use? Could you connect to above ground soil pipe?
Its roughly about 2.5 meters - gully would work (guessing thats ok with waste water from shower)?

There will be a soil pipe running across underneath so if I could drop the waste in somewhere (maybe) jobs a gooden.
Go for 2nd option, I can’t remember if gullies are allowed anymore.
Sponsored Links
If 110mm pipe is above ground, connect to that with a boss.

If you need to connect below ground, you'll have to join to that and come up to ground level in 110mm pipework. Then either make a direct connection to the drain with a suitable boss adaptor, or fit a gully.
Thanks again guys. Can I just check Ive taken a picture of the building as you can see where I have circled 1 is the main 110mm soil waste which goes under the house. Am I correct in thinking I need to put an inspection chamber here as the waste will be changing direction?

And then as you see from number 2 (excuse the pun) it comes down and will join a 110mm soil pipe there again because the waste will be changing direction I'll need another inspection chamber?

All this will be above ground as you can see there's a bit of a drop from the double doors so we need to build up a patio of some form

If anyone has a brain wave as to the best way to go about it that would be brilliant.

Cant add the pic from my phone
Last edited:
Hopefully this will allow me to upload the picture..... And ignore the downpipe this wont be connected to the waste this goes (eventually) to a soak away :)


  • image.jpg
    170.4 KB · Views: 148
You've got 2 110mm pipes in the pic, are these coming out of or going into the property?

Your shower waste ideally needs to go into a 110mm stack pipe, which then needs to connect to the drain. Stack can be capped with an Air Admittance Valve, and would be better connected to the run under the house via an inspection chamber, (the shallow, 300mm diameter type would suffice, looking at the depth of the existing drain.)
Yeah there is a stack pipe further in (connecting the main waste from the house). We had to bring this 40mm one out as the joists were running the wrong way for us to be able to connect. The other 110mm pipe is tge radeon pipe so ignore that one
You cannot have a 2.5 metre vertical drop on a 40mm waste pipe. as Hugh Jaleak, run 110mm soil pipe up the wall and use a boss pipe to connect the shower,
Are you planning on draining grey water into a fresh (storm) water drain??
Why cant I run a 40mm waste pipe up the wall to 2.5m? And no the grey water will run into the 110mm soil pipe.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links