Is it normal/ok for a basin waste pipe to 'twist' under the sub floor?

[mjgreen81]

Hi,

I'm currently doing a renovation to my under stairs ground floor toilet. Last week I had the plasterer in and I have noticed that he had rotated the waste pipe where it disappears through the chipboard subfloor 180 degrees to allow him better access.

I am not really sure how the waste pipe is connected under the floor, but I had presumed that the waste pipe would be solvent welded and shouldn't really move (the connections above the subfloor are solvent welded).

Is it normal for the pipe to be able to twist? It requires a little force, but moves fairly easily. In a way it makes life easier as I can move the pipes to suit the install when I get everything connected back up, but I am a little concerned that the twisting might be a sign of a possible issue in the connection under the floorboards.

Thanks

 

[denso13]

Could be into a rubber connection/straight boss reducer, in which case it could rotate.

 

[Madrab]

I have to say if the pipe has been manipulated and moved then there's always a chance that a seal or similar has been compromised. I'd test it with copious amounts of water down the waste and see if there's any issues that arise. The alternative is to quickly open it up and take a look.

As suggested it could be a push fit type connection but without seeing it then hard to know and testing is all that can really be done to reassure. Though I must be honest and say the plasterer shouldn't be twisting anything with knowing what's going on underneath.

 

[mjgreen81]

I have to say if the pipe has been manipulated and moved then there's always a chance that a seal or similar has been compromised. I'd test it with copious amounts of water down the waste and see if there's any issues that arise. The alternative is to quickly open it up and take a look.

As suggested it could be a push fit type connection but without seeing it then hard to know and testing is all that can really be done to reassure. Though I must be honest and say the plasterer shouldn't be twisting anything with knowing what's going on underneath.

How could I open it up? The floor boards are big tongue and groove chipboard sheets and I can't really see how I could lift them without damage.

 

[denso13]

How could I open it up? The floor boards are big tongue and groove chipboard sheets and I can't really see how I could lift them without damage.

It'll be fine IMHO, turning is fine on whatever kind of push fit it is. If it was solvent weld it would be broken and hanging loose.

 

[mjgreen81]

It'll be fine IMHO, turning is fine on whatever kind of push fit it is. If it was solvent weld it would be broken and hanging loose.

Thanks, I think so too but as I am not sure how a waste pipe is normally connected underneath the floor I was a little concerned.

It's a good suggestion from the other reply to pour a load of water down there just to make sure nothing unexpected happens before I lay the floor and finish everything else.

 

[denso13]

It's a good suggestion from the other reply to our a load of water down there just to make sure nothing unexpected happens before I lay the floor and finish everything else.

Of course, you would normally do that anyway.

 

[Madrab]

Unless it's compression and the twisting has loosened the nut or the SW wasn't glued properly and the twisting has been enough to click it loose but it stayed in the fitting. I've also seen older push fit seals leak once the seal was twisted and broken as they tend to stick to the pipe over time, that's why IMHO, push fit, once taken apart, really shouldn't be re-used.

Seen both instances more than once in my time, in fact a SW bath waste pipe did exactly that to me 3 days ago, previous installer had only glued half of it and it sprang loose when I was cutting in a tee but it stayed in the elbow.

Certainly not saying any of these would apply to this one but for all it is to check that it's ok.

 

[RrogerD]

Personally i think that I would cut open the floor and have a look. Better that then get all the floor down only to find that you have a leak later. Perhaps use a hole-saw and put a camera down?

 

[Madrab]

All I would say is that if it was me at a clients house and they mentioned that a waste pipe had been twisting under the floor by the plasterer moving the waste, 1st of all the plasterer's ears would have been burning and (edit) then I wouldn't hesitate to get the multitool out and check. As suggested, for all of the 5mins it takes to check for peace of mind, If I've learned anything over the years it's best not to take a chance.

If it's into a rubber reducer say in a soil pipe connection then usually fine, anything else I'd be taking a closer look at it.