Flexi poo pipe

[Dee]

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

[Jenki]

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.

[Dee]

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 

[Jenki]

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

[Mike]

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.

[SteamyTea]

I have diverticulitis, all I want is a smooth pipe.

 

[Dee]

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?

[SteamyTea]

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.

[Dee]

😄 🤣 

 

Edited May 1, 2023 by Dee

[Dee]

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

[Dee]

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?

[Dee]

That's a genuine question guys!

[Jenki]

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.

[Conor]

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.

[George]

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.

[Dee]

Conor, sorry but I don't understand. Can you elaborate for this civil ?

Thanks

[Dee]

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?

[Carrerahill]

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

[George]

Swap the sink and toilet positions. 

[Carrerahill]

8 minutes ago, George said:

Swap the sink and toilet positions. 

How would that work? 

[Dee]

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

[George]

I was thinking you could either send it outdoors or you could run the 110mm pipe parallel to the joists. 

[Nickfromwales]

@Dee

You can get much longer lengths in by removing one noggin and lowering a length of pipe down, then under, then rotate it 90^o 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!

[Dee]

No noggins

Kitchen ceiling, joists, void, joists but no noggins. 

Stay there! I have another question for :)

[Dee]

How much wood can I notch out of a ceiling joists to get the fall I need for the soil pipe?