Steve H wrote:
And what is best for ceramic tiling over boards?
Our kitchen was done nicely with cement based adhesives and grout. After a
couple of years most are loose as a result of both the flexing of the boards
and the drying effect from ch pipes that run under the floor. The tiles are
still in place, and it is not much of an inconvenience, but what should have
been used by the contractor?


A thick bed of flexible cement, but you have to stabilise the surface
first, which is why one always is recommended to screw waterproof ply
over the lot before starting. And only a certain amount of flexure can
be catered for anyway..sometimes you have to remove floor boards and
stiffen up the joists first.