Relocating stench entry to plastic welded stack

[muffking]

Hi guys.
I'm in the process of stripping my bathroom ready for a new layout, but I've come up against an obstacle.

The existing 100mm poo pipe needs relocating, but everything is welded in. The bath waste position is ok, but I need the poo pipe to come out the left side instead so I can fit a 90 degree bend and run it along the left hand wall.
What are my options?

 

[Doggit]

Are you sure it's welded; pull on the RH waste pipe, and see if the main branch swivels. If it is indeed welded in, then you need to cut it further down the stack, and fit a new section, then the branch and pipework to the new toilet position, and then the vent pipe etc etc.

 

[muffking]

Thanks Doggit. Pulling the poo pipe of the right turns the whole branch. The top section of the stack has plenty of play toward the loft space though. What are the chances that if I cut the branch section for this floor to replace with a new one that I'll be able to lift the stack in order to drop it in to a new branch section?

 

[Doggit]

You're luck may be in. See if you can wiggle the soil pipe out of the branch, then remove the bath outlet and see if you can get a cap/stopper for the resulting hole. Then turn the branch round 180 degrees, and drill into the boss on the other side, and refit the bath outlet pipe. You need to be careful how you drill the boss out though, as you don't want anything to drop down into the soil stack, or you may end up with a blockage. Do you know where the manhole cover is if anything drops in.

 

[muffking]

I may worded my response wrongly as the whole stack turns, not just the branch. I'm'pretty sure it's welded in and the whole branch tries to turn when I pull on the poo pipe.

I'm thinking that I need to find a 100mm branch section, preferably push fit, then cut the stack and feed the new branch between both sections of the stack. Does this sound about right?

 

[Doggit]

Find out where it turning then. As long as the seal remains tight lower down, then you've still achieved what you want. If you can wiggle the branch pipe out, then that should tell you if it's been welded, or just stiff. The danger you've got in turning it, is to damage the seal on the roof, so you need to find some way of making sure it doesn't turn. As the upper pipe is just the vent, you could drill a hole through it, and poke in stick that jams it against the wall; then a bit of sealant will seal it afterwards. But you'd need to get someone to grip and hold the lower section (just not sure where) if you want to keep that in position.

 

[muffking]

Just been up for another look and twisting the pipe tuns the lower half of the stack with it, which is connected to the downstairs toilet, so it only turns a little bit.
On the flip side I checked the top of the pipe for the vent and it just vents above the attic floor in to the loft space, so cutting and lifting the upper section of the pipe would be a breeze.
How hard do you think it would be to remove the existing branch and fit something like this as the outside diameter of the pipe measures 110mm, so I'm hoping this would fit - https://www.plumbcenter.co.uk/product/center-single-branch-110-mm--black/

 

[Doggit]

Wickes is cheaper, and will happily take it back if it won't work. It looks as though you're on the right track, so just try and get things apart. If the vent pipe goes up into the loft, then remove that one first, then get someone strong to hold the downstairs pipe, and then wiggle the upstairs branch to loosen it. You need to dismantle it, and get the part necessary to rebuild it, but I'll be surprised if you can't reuse the existing bits. When you reassemble everything, you can either wipe a bit of washing up liquid (or soap) on the pipes to get them to slide in, or get a can of spray silicone which is much easier to use.

The worst case scenario, is that you'd need to start rebuilding from the downstairs toilet.

 

[muffking]

Thanks. I'll add stripping the stack to the list of jobs to complete the bathroom. Hopefully it will come off easy enough as the downstairs is boxed in. Ideally I'd like to get it in the corner of the room, but will settle for the waste pipes pointing the right way

 

[Hugh Jaleak]

That to me looks like solvent weld, and that aint coming apart.

Suspect the only option would to be to cut it lower down, fit a coupling and replace the upward section as required, re-joining to the vent section above a new branch for the WC. This will also give you the advantage of not having to block off the existing boss where the bath is currently connected, as I suspect that wont be coming apart either....

 

[muffking]

If that's the case then I'm screwed as there is another branch just below floor level for the sink waste (that's the white pipe on the right that looks like it's coming out from the floor). The problem is that there is only 1" of 110mm pipe showing between the two branches, so not enough to fit another branch on to.

Is it possible to Dremel bits off the branch and sand the pipe smooth'ish enough to solvent weld (or push fit) a replacement branch?

 

[Doggit]

You'd need to wack out the boxing in the room below to allow you to get at the lower pipe, then you can start to rebuild. Or you get someone more professional in.

 

[Hot&Cold]

Hi guys.
I'm in the process of stripping my bathroom ready for a new layout, but I've come up against an obstacle.

does the alteration of soil/drain layout involve building regulation sign off ?

Just asking as see many diy shyte pipes leaking or even blocking,ok for me as i can charge for upgrade work to the latest building regulations requirements. Then the customer needs to obtain retrospective building regulation sign off when they come to sell the property or if home insurance is involved in a claim.Some house owners tell a few fibs but these are easily called out.

sorry to be negative but we see diy shyte work every day and if diy fiddlers followed good practice procedures,the in force regulations,testing procedures and testing sign off with certificates they would be ok.

been there seem it

 

[muffking]

Point(s) taken. Fortunately the plumber who will finish the job is registered, my qualifications extend only to the electrical side, although I've done enough builds to know my limits, and this may be one of them.

In the mean time i'm going to start with the sink waste and have bought a load of solvent weld parts. Before I start cutting the waste pipe to suit is there anything I need to know about solvent welding that may not be obvious?

 

[Doggit]

Get everything set up dry first, and make sure everything fits, then as you do each joint, you recheck for a dry fit first, apply solvent to both surfaces, put parts together, and then turn 90 degrees to ensure even spread of solvent. Check and measure twice, and fit once.