rherbert

Thanks for your reply.

The builders are still saying that the new grout will eventually take when they rake down deep enough into the old wall grout. However, each time they do this the floor grout just pops up to expose the shiny smooth wall grout.

Can your clarify a few points for me?

Do they have to get all the old wall grout out as they say this is an impossible task as it sank to under most of the tiles? Also they have no problems removing the floor grout but find it really hard to remove that original ceramic wall grout.

Is the problem caused by the original grout being wall grout as we have never had this problem regrouting floor on floor grout?

I really do not want to reach a stalemate with the builders as everything else is fine.