Can someone answer this?

[Rizzle from the Portizzle]

but joints allow for no movement ok if on a sand and cement wall on concrete blocks. but will push the tiles off the wall with any movement grout joints are like surspension on are car allow for a smooth ride but a rought ride without them . so a 1800 mm wall tiled in 600x600 will allow 10mm of compressed movement between joints before pushing tiles off wall