This job is done in- and outdoors: the surface of the wall or floor is first carefully prepared, and then the tiles - which come in many shapes and sizes and of many different materials such as marble, ceramics, stone, brick etc. - are then affixed to it. The tiles can be for decorative or for utilitarian purpose: in a bathroom or toilet they would serve both purposes, by having a pleasing appearance at the same time as making it easy to keep clean. Tilers work either alone or in teams if the job is very large.