"David" wrote in message
...
I would think he's talking about a block sealer, this seals the surface
of the blocks and seals/stabilises the sand between them, with the joint
sealed nothing grows between them. Buy one that wont affect the colour
(unless you want a darker wetlook).
--
David

Thanx David and to all else who replied.

What is this block sealer stuff? Where do I find it in B&Q? Is it a
sand-like substance or a liquid or what? Whats the best way to apply it?

Thanx

AMO