cracks in tiles causing leak? Advice and information on tiling and fixing tiles to a variety of surfaces

[LS]

my bathroom has tiles along the wall adjacent to the bath. not sure what is wrong but there is water collecting below bath frequently and this comes down on room below.

The grouting seems ok, no cracks or gaps. About 4 or 5 of the tiles seem to have a hairline crack running their whole width. Would this be letting water in them. I am also not sure but I think this happens - if one has a long shower, then there is water beneath the bath. (the tiles may have been done about 8-9 years ago)

If the tiles are causing problems can I have a quick fix solution like painting something on the tiles? cannot think of re-tiling the whole bathroom at present.

PS we use only for showers not bath. Please help!!

[welsh brickie]

Test the area by showering the tiles and look if water is penitrating,but with a small hairline crack its doubtfull.also stand in the bath to see if there is any movement,the seal between the bath and the tile is the usual culprit for leaks.
There could also be a leaking joint in the pipe causing the leak.