How to remove sink waste from soil stack boss

[Sard]

Hi,

I'm removing a second sink I had in my utility room that connects to a soil stack (see attached photo). I want to get it as close to the stack as possible as the whole thing needs to be boxed in. The uPVC waste pipe looks like it's been glued on with solvent. Any advice on how I can get it removed and how to cap it off?

 

[Madrab]

The boss adapter will be glued into the stack but it look likes it might be pushfit for the waste pipe, therefore the pipe should be able to be removed, it may just be 'stuck' to the seal, give it a good twist both ways and see if it loosens. Then you would use a 40(32)mm plug, pipe size dependent, to slot into it. If it's never to be used again then use a little silicone adhesive on the plug, as the rubber seal, once loosened, may be compromised.

 

[Sard]

The boss adapter will be glued into the stack but it look likes it might be pushfit for the waste pipe, therefore the pipe should be able to be removed, it may just be 'stuck' to the seal, give it a good twist both ways and see if it loosens. Then you would use a 40(32)mm plug, pipe size dependent, to slot into it. If it's never to be used again then use a little silicone adhesive on the plug, as the rubber seal, once loosened, may be compromised.

Thank you. I've managed to get the waste pipe off, but the light grey ring isn't coming off and is just turning freely. I assume that I can just push fit the plug you mentioned straight into the light grey ring and put some solvent weld on for good measure?

 

[Madrab]

The grey ring doesn't come off, well it does but that's when the seal is being replaced and it's needs to be popped off but for your application the plug should just pushfit in there. As suggested if it's to be permanent then a little silicone adhesive on the plug before it's fitted.

No, solvent cement shouldn't be used.

 

[Sard]

Thanks again. I had a go with a plug. Just wanted to check this is what you meant before I apply silicone adhesive (i.e. sanitary sealant?)

 

[Madrab]

That's it, is it quite a snug fit in there? I would use silicone adhesive rather than a silicone sealant, a silicone adhesive sets into a firmer, more permanent rubber than sealant does but if you have sealant to hand then that should do fine.

 

[Sard]

Yep, it's a snug fit. Would something like no nails work? I've got plenty of that lying around.

Thank you again, I sincerely appreciate your advice and prompt replies.

 

[denso13]

Yep, it's a snug fit. Would something like no nails work?

If it is a snug fit I would just fit it dry. No need for anything else.

 

[Madrab]

No more nails wouldn't be my first choice no, is there anything on the stack above toilet etc?

If so then i'd recommend a little silicone or similar as a belt'n'braces just in case the stack backed up for any reason and it popped that plug

 

[Sard]

Ok, understood. There is a family bathroom and toilet above that feeds into that stack.

No more nails wouldn't be my first choice no, is there anything on the stack above toilet etc?

If so then i'd recommend a little silicone or similar as a belt'n'braces just in case the stack backed up for any reason and it popped that plug