Dee Posted May 1, 2023 Share Posted May 1, 2023 (edited) Hello, I need to run a horizontal poo pipe between the joists and a suspended floor above. The distance is about 3m but not enough wiggle room to fit rigid 110mm pipe. Is is OK with regs to use flexi pipe for soil waste? It will have a slimline loo attached and will run in a straight line, no bends. Thanks Edited May 1, 2023 by Dee Forgot detail Link to comment Share on other sites More sharing options...
Jenki Posted May 1, 2023 Share Posted May 1, 2023 Over 3M you will need a fall, and Flexi pipe is just asking for problems, it will sag, and that means solids will separate from liquids and it will block. Don't do it.... Why not join smaller lengths of pipe and ensure all joints are supported and the fall is correct. 2 Link to comment Share on other sites More sharing options...
Dee Posted May 1, 2023 Author Share Posted May 1, 2023 The joists are at right angle to the pipe so it's nigh on impossible to thread even short lengths . A flexi pipe eould be supported the joists it runs over. Any suggestions grateful received thanks Link to comment Share on other sites More sharing options...
Jenki Posted May 1, 2023 Share Posted May 1, 2023 (edited) It's hard to tell, but if there is space under the joists for the pipe I can't see why you can't get the pipe in there? Flexi is a bad idea. You will regret it. If it can't be done with solid pipe you need to re-design IMO. Edited May 1, 2023 by Jenki Spelling Link to comment Share on other sites More sharing options...
Mike Posted May 1, 2023 Share Posted May 1, 2023 I agree with @Jenki - a flexi pipe is guaranteed to cause problems in the future. You need a standard smooth-bore pipe laid to falls of at least 18mm/m. If it needs to go through the floor space then multiple short lengths glued together would work or, if you have an outside wall, cut a hole and feed a pipe through from outside. Fixing the pipe to the wall above floor level is another option, even if this does mean reconfiguring the room. Link to comment Share on other sites More sharing options...
SteamyTea Posted May 1, 2023 Share Posted May 1, 2023 I have diverticulitis, all I want is a smooth pipe. 1 Link to comment Share on other sites More sharing options...
Dee Posted May 1, 2023 Author Share Posted May 1, 2023 Thanks for the feedback. Flexi pipe is a no go. I'll try again with shorter lengths as running the pipe above the floor eont eork as there is a door in the way. Is there anynlimit yo hos many joins I can use? Shoukd they be glued or push fit? Link to comment Share on other sites More sharing options...
SteamyTea Posted May 1, 2023 Share Posted May 1, 2023 9 minutes ago, Dee said: any limit to how many joins I can use? Should they be glued Have you copied my autocorrect? I never found glue sniffing much fun. Link to comment Share on other sites More sharing options...
Dee Posted May 1, 2023 Author Share Posted May 1, 2023 (edited) 😄 🤣 Edited May 1, 2023 by Dee Link to comment Share on other sites More sharing options...
Dee Posted May 1, 2023 Author Share Posted May 1, 2023 (edited) Thanks for the feedback. Flexi pipe is a no go. I'll try again with shorter lengths as running the pipe above the floor wont work as there is a door in the way. Is there any limit to how many joints I can use? Should they be glued or push fit?. Edited May 1, 2023 by Dee Spelling Link to comment Share on other sites More sharing options...
Dee Posted May 1, 2023 Author Share Posted May 1, 2023 Thanks for the feedback. Flexi pipe is a no go. I'll try again with shorter lengths as running the pipe above the floor wont work as there is a door in the way. Is there any limit yo how many joints I can use? Should they be glued or push fit? Link to comment Share on other sites More sharing options...
Dee Posted May 1, 2023 Author Share Posted May 1, 2023 That's a genuine question guys! Link to comment Share on other sites More sharing options...
Jenki Posted May 1, 2023 Share Posted May 1, 2023 If it's multiple joints solvent weld would give a more rigid solution, but both will work, just support the joints and ensure the pipe cuts are clean, square and free from burrs to minimise the chance of flushed waste catching in the gaps. And make sure the fall is correct. 1 Link to comment Share on other sites More sharing options...
Conor Posted May 2, 2023 Share Posted May 2, 2023 General rule of thumb in the civils world is fitting every 5x pipe diameter, i.e. max every 550mm (on average.) Can be less over sort runs. 1 Link to comment Share on other sites More sharing options...
George Posted May 2, 2023 Share Posted May 2, 2023 Can it go through one of the walls or straight through the floor? If it's a utility or out of sight area, it could run at ceiling height and be boxed out. Bathrooms are often designed around the SVP & toilet - sink & bath/shower drains are a little more flexibility but still needs careful thought. Link to comment Share on other sites More sharing options...
Dee Posted May 2, 2023 Author Share Posted May 2, 2023 Conor, sorry but I don't understand. Can you elaborate for this civil ? Thanks Link to comment Share on other sites More sharing options...
Dee Posted May 2, 2023 Author Share Posted May 2, 2023 See above drawing. The poo pipe in question will connect a new 1st floor cloakroom loo into an existing vertical soil stack. It's very tight access between the floor joists and the ceiling below. I think I can just about get the fall but not sure how to thread the horizontal poo pipe through the gap. How short can I make the sections? Link to comment Share on other sites More sharing options...
Carrerahill Posted May 2, 2023 Share Posted May 2, 2023 (edited) 36 minutes ago, Dee said: See above drawing. The poo pipe in question will connect a new 1st floor cloakroom loo into an existing vertical soil stack. It's very tight access between the floor joists and the ceiling below. I think I can just about get the fall but not sure how to thread the horizontal poo pipe through the gap. How short can I make the sections? Can't you remove any obstructions between two joists, then drop the pipe down parallel to the joists then rotate it under the joists? It is not clear from the photo what the full situation looks like but from the area I can see it looks like there is a good space below the joists. I would also be willing to reconfigure, temporarily remove things just to get this pipe in properly. I'd not really want a jigsaw soil pipe, although I am sure it could be done. Could you not even get 1m pieces down and then rotate? Another thing to consider, is there any outside wall access that you could core a hole to feed the pipe in? I have seen that done before. Edited May 2, 2023 by Carrerahill Link to comment Share on other sites More sharing options...
George Posted May 2, 2023 Share Posted May 2, 2023 Swap the sink and toilet positions. 1 Link to comment Share on other sites More sharing options...
Carrerahill Posted May 2, 2023 Share Posted May 2, 2023 8 minutes ago, George said: Swap the sink and toilet positions. How would that work? Link to comment Share on other sites More sharing options...
Dee Posted May 2, 2023 Author Share Posted May 2, 2023 Carrerahill; good points made. The space is empty of anything but pipes as its under a catslide roof that we built a dormer window into to creat a bathroom and small cloakroom. I can feed the pipe from the outside as there is a long window bang in the way. I have 1.2m lengths of poo pipe but even these are hard to rotate( I get where you're coming from. I'll look into removing some joists as I hadn't considered that as an option. I think George thought I could put the loo on the outside wall and have the pipe external but there's no manhole that side if the house plus the window is there so no good. Appreciate your feedback Link to comment Share on other sites More sharing options...
George Posted May 2, 2023 Share Posted May 2, 2023 I was thinking you could either send it outdoors or you could run the 110mm pipe parallel to the joists. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted May 2, 2023 Share Posted May 2, 2023 @Dee You can get much longer lengths in by removing one noggin and lowering a length of pipe down, then under, then rotate it 90o to bring it perpendicular to the joists? Only a couple of connectors required then. DO NOT use solvent weld The snots of glue will cause havoc! 1 Link to comment Share on other sites More sharing options...
Dee Posted May 5, 2023 Author Share Posted May 5, 2023 No noggins Kitchen ceiling, joists, void, joists but no noggins. Stay there! I have another question for :) Link to comment Share on other sites More sharing options...
Dee Posted May 15, 2023 Author Share Posted May 15, 2023 How much wood can I notch out of a ceiling joists to get the fall I need for the soil pipe? Link to comment Share on other sites More sharing options...
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