On Sun, 06 Nov 2005 10:12:11 -0000, rrh wrote:

I want to put ten mega-expensive such tiles above a sink as a
splashback, on
a plaster wall. They are essentially coloured glass, though in some cases
with painted or fired-on opaque decoration. The wall is painted a neutral
colour. The wall or whatever is under the tiles will show through them,
at
least in places. If I am forced to choose a coloured adhesive and grout I
will probably go for grey, making sure the tiles are fully bedded in with
zero air gaps in the adhesive. But what I would really like is something
colourless. The tiles would be in two rows of five with the lower row
supported by the washbasin. Is clear sanitary silicone, used as both
adhesive and grout, a real no-no in these circumstances? The shop can't
help.

Silicone chemically bonds to glass, so no problem that side, it also
sticks reasonably well to plaster, but due to its low modulus will not
technically satisfy BS5980. Your big problem IMHO, is getting a
bubble-free layer behind the tiles. I expect whether the bubbles are tile
side or wall side they will show. As you are probably aware, silicone is
awkward stuff to work with. My best suggestions are to use a paste
adhesive (cement is a no-no on plaster), possibly pigmented to taste, but
check with the manufacturer for compatability. Have you considered mirror
corners for fixing them? Perhaps even mount a mirror and stick the tiles
with a border of silicone. That might be quite attractive.

John Schmitt

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