wozza Posted June 24, 2019 Share Posted June 24, 2019 Hi All, What is the best method to connect a 40mm waste pipe (from a ground floor shower) to the soil pipe - the pipe will be underground in the hardcore / mot. Is it ok to use the rubber bung things underground? Link to comment Share on other sites More sharing options...
Onoff Posted June 24, 2019 Share Posted June 24, 2019 I'd solvent weld into a boss. 1 Link to comment Share on other sites More sharing options...
PeterW Posted June 24, 2019 Share Posted June 24, 2019 No.1.... use 50mm not 40mm No.2.... can you not get a 110mm direct under the shower and save yourself the hassle ..?? No.3... strap boss is a no-no, use a tee and a reducing insert if you have to. 1 Link to comment Share on other sites More sharing options...
ToughButterCup Posted June 24, 2019 Share Posted June 24, 2019 1 hour ago, wozza said: [...] Is it ok to use the rubber bung things underground? Ahh, you've never used one underground then.... hmmmm 1 Link to comment Share on other sites More sharing options...
ProDave Posted June 24, 2019 Share Posted June 24, 2019 Just be aware that UK plumbing fittings are described in strange ways. e.g I bought a 110mm to 50mm reducer from ebay. It was just that. Shame that UK "50mm" waste pipe is more like 63mm diameter. 1 Link to comment Share on other sites More sharing options...
PeterW Posted June 24, 2019 Share Posted June 24, 2019 50mm is 50mm ... outside of a socket is probably closer to 56mm but that is wall thickness. This is the adapter you need underground. Put it so the adapter is at the top of the tee branch to stop it collecting crud ..... 50/110mm adapter 1 Link to comment Share on other sites More sharing options...
wozza Posted June 24, 2019 Author Share Posted June 24, 2019 Thanks all for the replies so far. The shower waste outlet is 40mm - it says to try and have at least 25cm of pipe before any bends. So my plan is to use solvent weld pipe and an adaptor as shown above by PeterW but in 40mm size - should the adaptor be solvent welded into the soil pipe? Thanks, Wozza. Link to comment Share on other sites More sharing options...
PeterW Posted June 24, 2019 Share Posted June 24, 2019 No - that sort of pushfit seal is fine underground. 1 Link to comment Share on other sites More sharing options...
joe90 Posted June 24, 2019 Share Posted June 24, 2019 I used a 40 to 50 adapter out of the shower trap and ran all my waste pipes in 50 to a main 110 within the house. I was advised 50mm tends to get blocked with crud a lot less than smaller sizes. 1 Link to comment Share on other sites More sharing options...
SiBee Posted June 24, 2019 Share Posted June 24, 2019 Flip side to that Joe, in my experience, the flow/speed is reduced in the bigger pipe so crud may not be washed down the pipe as good. I would not hesitate to use the bigger size though having replaced many 32mm runs which have become 3/4 blocked with solidified soap fats ect 1 Link to comment Share on other sites More sharing options...
ToughButterCup Posted June 25, 2019 Share Posted June 25, 2019 5 hours ago, SiBee said: [...] I would not hesitate to use the bigger size though having replaced many 32mm runs which have become 3/4 blocked with solidified soap fats ect Excuse the naive question: doesn't that just treat the symptom? 1 Link to comment Share on other sites More sharing options...
Onoff Posted June 25, 2019 Share Posted June 25, 2019 50mm here on the original advice of @Nickfromwales. Bath, shower empty quicker and quieter. Basin is 32mm solvent weld into a reducer in a 50mm tee. Don't forget an anti siphon trap on the basin if you do this. Stops all that gurgling. Have to say my wastes flow like a dream so far. (Must check the hair trap in the wall drain... ? ) 1 Link to comment Share on other sites More sharing options...
SiBee Posted June 25, 2019 Share Posted June 25, 2019 7 hours ago, AnonymousBosch said: Excuse the naive question: doesn't that just treat the symptom? onoff kind of answered your question. The symptom? well how are you going to stop people washing their hands with soap thats provided? Not sure if different types of soap help? In a public wc which gets a lot of traffic you can get heavy build up (I may have some old pictures somewhere for interest) Hot water helps but not everyone will wait for a decent flow of hot water or run enough to flush away stuff. Quick in and out and get on with the days business. Link to comment Share on other sites More sharing options...
ProDave Posted June 25, 2019 Share Posted June 25, 2019 17 hours ago, PeterW said: 50mm is 50mm ... outside of a socket is probably closer to 56mm but that is wall thickness. This is the adapter you need underground. Put it so the adapter is at the top of the tee branch to stop it collecting crud ..... 50/110mm adapter My point is, the sizes are not that "standard" Go to one of the sheds, and buy a length of "40mm waste pipe" and try fitting it into an OSMA solvent weld fitting. It will be too loose. The 50/110 fitting I bought on ebay indeed had a pipe hole exactly 50mm in diameter, no UK "50mm" pipe with it's OD of 56mm or whatever would fit in it. I learned LONG ago to buy all your waste pipe and fittings from the same place at the same time, then if something does not fit, you can take it back. Link to comment Share on other sites More sharing options...
Gone West Posted June 25, 2019 Share Posted June 25, 2019 I find this useful. Pipe Sizes and Dimensions Chart.doc 1 1 Link to comment Share on other sites More sharing options...
wozza Posted June 25, 2019 Author Share Posted June 25, 2019 (edited) Ok Guys, Please see my crude diagram below and let me know if its ok (its not to scale) My plan is to run the soil pipe up to and level with concrete sub floor - to then add 110mm to 50mm reducers so that the 50mm pipe runs through the PIR insulation and then straight up to the sink and the shower. The shower waste will need to have the screed cut out to fit the waste flush with the floor when the tray is fitted so I intend to take it straight up to start with (so the floor can be laid) then when the floor area is cut out, it can be shortened and the bend added. The length of the pipe from the shower to the soil pipe with only be about 300mm before the bend. Thanks, Wozza. Edited June 25, 2019 by wozza Sorry the first pic is wrong - it should be 50mm pipe - cannot delete it doh 1 1 Link to comment Share on other sites More sharing options...
Onoff Posted June 25, 2019 Share Posted June 25, 2019 Crude? Bang tidy "sketch" that. ? 1 Link to comment Share on other sites More sharing options...
wozza Posted June 25, 2019 Author Share Posted June 25, 2019 2 hours ago, Onoff said: Crude? Bang tidy "sketch" that. ? 10 mins in powerpoint Link to comment Share on other sites More sharing options...
Susie Posted November 16, 2023 Share Posted November 16, 2023 Did this all go to plan @wozza? I am in similar position a bungalow with concrete slab and insulation above then screed. I am thinking I need the shower and sink waste (white) in the insulation like you but joining a branch that then joins up to the terracotta waste in the hardcore with two boses one for toilet and one for sink and shower (white pvc) branch. On paper the inspection chamber has been swopped for a rodding point sending all waste to external stack on opposite wall. Link to comment Share on other sites More sharing options...
wozza Posted November 20, 2023 Author Share Posted November 20, 2023 Hi @Susie It worked fine, but make sure your measurements are bang on. Wozza. 1 Link to comment Share on other sites More sharing options...
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