hotnuts21 Posted October 25, 2022 Share Posted October 25, 2022 Hi, We are having a kitchen island in our extension and it will house the dishwasher and hob. So I need to get a cold water supply in and a waste out. I'm due to lay the insulation for the UFH and screed tonight and just wondering whats the best way to tap into the waste would be as it's going to be below ground level, can I drill a hole and use a rubber connector? I presume it needs to go into the waste as low as possible. I'm going to use 43mm waste pipe, the run from island to wall is about 1.8m and the run along the wall just under 3m. The photo is what I'm trying to tap into. Link to comment Share on other sites More sharing options...
hotnuts21 Posted October 25, 2022 Author Share Posted October 25, 2022 The green line shows the run of the proposed waste. Into the corner. Link to comment Share on other sites More sharing options...
markc Posted October 25, 2022 Share Posted October 25, 2022 If the connection is in the insulation I would want a proper moulded or welded spigot connector. Also, have you thought about access in case of a blockage? 2 or 3 90 degree bends in 40mm pipe is likely to block at some point 1 Link to comment Share on other sites More sharing options...
hotnuts21 Posted October 25, 2022 Author Share Posted October 25, 2022 Yeah thats why I was asking, im worried about it not being glued/permanent. Ive seen this, which I could potentially use by pulling out the one thats there, but im not sure if I can solvent weld into the universal boss. There will only be one 90 deg bend, where the pipe runs from the island to the wall, I was thinking of putting a t at the island with a 45 off it and haveing two pipes coming up, one for rodding and one for the dishwasher waste, so I could rod down to the corner/90 at the very lease. https://www.screwfix.com/p/mcalpine-drain-connector-black-110mm/469JG? (can you solvent into these? universal bos'?) Link to comment Share on other sites More sharing options...
PeterW Posted October 25, 2022 Share Posted October 25, 2022 Get rid of the bend ..! Go straight to the corner, do not pass Go and do not collect £200…. Remove the brown fitting that looks like a standard coupling and replace with a proper boss - you have the issue that the socket is too high and you may need to dig some of the concrete out around it as that will have a double layer of fitting / pipe within it and you cannot solvent weld to poly. What is the pipe leading into the top..? Staying or going ..?? 1 Link to comment Share on other sites More sharing options...
hotnuts21 Posted October 25, 2022 Author Share Posted October 25, 2022 The collar just above the concrete is the top of a rest bend, and yeah I just found out I can pull the top part out 😆. Although its going to be a lot of hassle cutting into the insulation, I think a straight run is best. The pipe going into the top is the temp kitchen waste I can play with that temporarily. Ive just realised that none of the standard push in boss pipes have a solvent weld attachment except the one that goes over a pipe, and thats going to cause issues. Link to comment Share on other sites More sharing options...
hotnuts21 Posted October 25, 2022 Author Share Posted October 25, 2022 Solvent weld boss strap might work if i can find one locally? Link to comment Share on other sites More sharing options...
hotnuts21 Posted October 25, 2022 Author Share Posted October 25, 2022 Just noticed this on the scrap pile from when we demolished the rear. Could cut this down and slide it into the bend so the boss is almost at floor level? Seems it needs a 63/5mm reducer? Link to comment Share on other sites More sharing options...
PeterW Posted October 25, 2022 Share Posted October 25, 2022 You don’t need to solvent weld under there - just put a boss in with a rubber plug and it gives you some wriggle room on the joint. would also suggest running 50mm solvent to the island and a Y branch in the pipe just before a slow elbow and then put a screw cap on the branch so you can always rod from that end. 2 Link to comment Share on other sites More sharing options...
hotnuts21 Posted October 25, 2022 Author Share Posted October 25, 2022 Don't need the solvent weld under the screed? I'm concerned if the rubber fails it's gone! Link to comment Share on other sites More sharing options...
PeterW Posted October 25, 2022 Share Posted October 25, 2022 How will it fail ..? It’s not in contact with liquids, it’s not UV exposed so why would it fail..? All the sockets on your underground waste have seals made of the same stuff and we don’t worry about those for 50/60 years..? 2 Link to comment Share on other sites More sharing options...
hotnuts21 Posted November 1, 2022 Author Share Posted November 1, 2022 Thanks for the help, a few sleepless nights getting ready for everyone and two nights of taking way too long to get everything down, the disadvantage of old houses nothing is square!! Anyway from the photo at the start, to fiinally finished floor. Thanks 🙂 I presume I can just trim all the edge insulation, upstand and polythene to floor level when its nicely hardened off? 1 Link to comment Share on other sites More sharing options...
markc Posted November 1, 2022 Share Posted November 1, 2022 (edited) Well done, yes trim the edge insulation but never hurts to keep a DPM upstand, it can go up behind plasterboard, plaster and skirts etc. stops any spilled water going where it’s not wanted and adds adds air tightness around the perimeter/through stud walls etc. Edited November 1, 2022 by markc 1 Link to comment Share on other sites More sharing options...
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