Tile Grout Cracking

[andy]

My floor is chip board i have had it tiles and although after a while most tiles have set there is some spring in the floor. Because of this the tile grout keeps cracking in some areas, is there any solution to this problem...... Please Help!!!!!!

[thedoctor]

It is possible to remove the grout and fill the joints with a silicone mastic Andy but this is a horrific job and almost impossible to keep neat. Also there is no guarentee that once done, the tiles themselves will not start lifting and even cracking as is common when floor tiles are laid on a floor which has not been properly strengthened.