>
> >Thanks again to all for the help with this; I'm now ordering a couple
> >of these to keep my BCO happy! I'll be fitting one either side of a
> >party wall, where a 4" soil pipe passes through (nearly horizontally). > >
> The collars are usually set into the wall so when they expand they
> can only move inwards to seal the space.
Oh, OK... I've actually ordered the ones you pointed me at earlier in this thread
They haven't arrived yet, but looking at the picture they seem to have fixing tabs which suggest they'd be flush mounted on the wall - is that not so? Should they be actually buried beneath the surface of the plaster then?
Thanks David