How Marble and Terrazzo is Set – Careers Involving the Laying of Tile
Helpers do most of the mixing of cement and mortar, which leaves the setters free to concentrate on their work. It takes only one look at a wall that has been improperly laid (where the joint lines do not run true) to realize the importance of accuracy for these workers. Where color is used, the appearance of a whole job can be ruined by an improper blending of hues.
When setting marble, the workers first lay out the job. Then they apply a special plaster mixture to the backing material and set the marble pieces in place. These pieces may have to be braced until they are firmly set. Special grout is packed into the joints between the marble pieces, and the joints are slightly indented. This indenting is known as “pointing up.”
Tile setters attach tile (thin slabs of clay or stone) to floors, walls, and ceilings with mortar or specially prepared tile cement. They set a sheet of metal mesh to the surface to be tiled and then apply the cement to it, raking it with a tool similar to a yard rake. When this “scratch coat” has dried, setters put a second coat of cement to the mesh and to the tiles and set the tiles in place. Some smaller-sized tile comes in sheets made by fastening a number of tiles to a special paper backing so that they do not have to be set individually. Glassy,
nonporous tile is used primarily for floors, and duller, more porous tile is used for walls. After the tile is set in place, the setters tap it with a block of wood or a tool handle to even out the surface. They finish by applying grout (a fine cement) to the set tile, scraping it with a tool to remove the excess grout and wiping it with a wet sponge.
Terrazzo workers lay a base (first course) of fine, dry concrete and level it with a straightedge. They then place metal strips wherever a joint will be placed or where design or color delineations are to be made. This metal stripping is embedded in the first course of concrete. Then the terrazzo workers pour the top course of concrete-a mortar containing marble or granite chips-and roll and level it. Different-colored stone chips are used to color whatever pattern has been planned for the finished floor. In a few days, after the concrete has hardened, the floor is ground smooth and polished with large polishing machines.
Unlike many construction jobs, these occupations are relatively free from routine. Each job is slightly different, and workers rely on their training and ingenuity to a great extent. Marble setters, tile setters, and terrazzo workers generally do not have immediate supervisors on the job. They often manage their own time, schedule their work, and have the responsibility of doing whatever is necessary to provide the best possible job.
Because these workers have an opportunity to plan the job, see that the material is delivered on time, and follow the work through the cleanup phase, they often feel a greater sense of satisfaction from the completed job than construction workers who are responsible for only one part of the total job.