Advise please - 32mm strap boss glued / rubber perished??

5 Jan 2009
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United Kingdom
Hi All

I’m looking to replace all this worn/leaking 32mm waste to Solvent Weld including the part going through the wall cavity as it it SW inside going to a basin waste.

I’m thinking the strap boss rubber has also perished but the wrap and this type of boss insert with small rubber seal will also need replacing?

How can this be done as I presumed both parts are glued on.

Will it all need replacing or can I drill it again with a 54/57mm holesaw?

Can I just replace the rubber boss grommet somehow?
or will I have to somehow snap/file/remove all the existing PVA strap as well?

This is the type I normally use going into branch 110mm T with the required glued in adapter (57mm hole)

link -


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The boss should be solvent welded. You might be lucky and find the other parts aren't sealed in.

I would firstly, make a careful attempt to remove the waste pipe from the Boss, (waste looks like polypropylene, which doesn't like the UV in sunlight and basically decomposes), given its vertical position, if you can keep the boss intact, then you may be able to simply insert your new waste into the existing fitting, and seal with some silicone or similar.

The whole soil pipe looks rather faded, which will make it brittle, so proceed with caution, any attempt to get too hands on with it could result in a much bigger job than you envisaged....
Do everything would hopefully stay in place except for the the old poly pipe?

I like the idea of carefully inserting new 32mm SW into it and silicone.
I can see the collar staying in place tbh just where it inserts has a very worn seal.

Why do they still sell these? It’s an awful design imo.

Looks like i will be hacking a new hole in the wall as well to replace section going through the cavity??

The soil itself yet discoloured is solid, well solid enough for me to banging heavy set double sets against it.

Thanks for replying
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Pipe going through wall should still be fairly solid, as sunlight wont have got to it, however, personally, for what it's worth, I'd change the lot. If you chip out the mortar around the bend where it goes into the wall, I'd think with a bit of pulling and/or twisting, you should be able to remove the old pipe, leaving you a suitably sized hole to insert the replacement pipe through, possibly just leaving you a small area to make good again.
The Soil Pipe will be uPVC, a different type of plastic, which fares slightly better in sunlight, however, it is recommended all exposed plastic is painted with an exterior grade gloss paint to help protect it from UV.
I ended up replacing it all even the 40mm that is out of sight.

I chipped around where it exits and it was PVC solvent pipe all the way to the basin.

The solvent weld pipe was nice and tight going into the Osma seals which were not perished.
I did have to coke the edge to make a ‘point’ to insert it plus bit soapy water spray.

All new in solvent weld plus added extra clips and tidied it all up.

Also added 2 soil pipe clips.

Thanks guys.

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