What is the proper method to apply sealer to tile and the grout in between.It is large shower made with 6x6 tiles covering the floor and halfway up the walls.Above the large tiles are very small glazed tiles.The lady of the house had it built butdoes not know if the handyman sealed it or not.I looked at the tile and grout and does not appear to be sealed.When opened the service door behind the shower head and faucets I also noticed standard sheet rock was used for backer to the entire shower.Problem Later?