On Sunday, 6 April 2014 09:42:15 UTC+1, harry wrote:

Solvent cement is what is used on some waste pipe fittings. (As opposed to
push in/Oring and the compression type)

Thanks Harry. I may have not been clear enough in my post; it is not the fact that solvent cement is required but rather that the gap-filling variety is specified by Osma for a strap boss whereas I've not seen the same by other manufacturers.

This could turn out to be a moot point as I'm actually leaning towards the use of a mechanical boss now:

http://www.mcalpineplumbing.com/land...tor-black.html

Not only does this remove the one-chance-is-all-youve-got aspect of solvent weld but it is also a fraction of the cost - only £10 compared to the £50 Osma setup (i.e. once degreaser and cement are factored in). Of course, I don't want to trade a financial cost with one of performance but I don't think I would be - particularly if I used a smear of silicone and a couple of jubilee straps to aid the integrity of the connection for peace of mind if nothing else.

It may well be prudent for me to have an access panel for this connection anyway and so I will be able to satisfy myself that it is sound and not leaking.

Mathew