To be able to inspect ceramic tile installations at the level of a professionally-trained floor inspector there are a number of things you must know. For instance, how tile is manufactured and classified will give you an understanding of the materials and what the tolerances are for specific types of tile. You should be knowledgeable about what constitutes proper installation. You have to be able to evaluate the tile work and determine whether the right tile was used for the installation. If you are planning on doing your own tile inspection before purchasing a house, do your homework. Having to remove or install new tile after you move in can cost you a lot of money.
Look at a tile floor and inspect it for lippage. Lippage is how level the tiles are in relationship to the adjoining tiles. If the tiles are not level it could mean they weren't set properly in the mortar, which can create problems that require reinstallation.
Check the tile installation for cracked tiles, loose tiles, lifting, chipping and splitting. All of these pertain to either the quality of the initial installation or to structural problems. These could also be created by excessive expanding and contracting of the building during seasonal freezing and thawing.
Look for crazing in the glaze of the tile. These are tiny fissures in the surface glaze caused by the tiles being cooled too quickly after they were fired in a kiln. These are inferior tiles and hold the potential for the glaze to shale off the surface.
Watch for cracked grout lines between the tiles, especially in showers and on counter tops. This is a sign of an old tile installation, a building that shifts or a sub-standard installation. Examine the grout closely to see if it looks dry and porous or if it has been properly sealed with grout sealer. Unsealed grout is porous and readily absorbs moisture from the atmosphere or from liquids being spilled on the floor. Check for stained grout.
Pull up a floor grate if there is one and look to see what the floor tiles are cemented to. A mortar bed is the best foundation for floor tiles.