Terrazzo flooring is typically installed over a concrete subfloor. Some installers add a thin layer of sand and cement to the concrete while others pour the terrazzo directly onto the concrete. Before installation can begin, the floor must be properly prepared to receive this material. First, metal divider strips are arranged to separate different colors or designs that are planned for the terrazzo floor. These strips are made from brass, copper or aluminum depending on the desired finish. The strips may be glued to the concrete subfloor using an epoxy adhesive or may simply be set into the sand and cement base, if applicable. Additional metal dividers are also placed at control joints along the concrete floor. This helps prevent the terrazzo from cracking due to shifts in the concrete. Finally, a concrete primer is added to the entire floor to help the terrazzo bond with the surface.
Pouring the Terrazzo
A terrazzo floor is made from a two part epoxy mixture. This mixture contains an epoxy resin and a complementary hardener, which must be mixed immediately before use because of their quick drying time. Some terrazzo floors use pigments and dyes to color the epoxy, while others use a clear finish. The epoxy is mixed and spread within the metal strips using a trowel. As soon as it has been poured, an aggregate mixture is spread across the surface. This aggregate may contain glass, marble or stone, and may be a blend of several different materials. The aggregate will settle into the epoxy as it hardens so that some stones rest at the surface and others are embedded underneath. One color at a time is poured and allowed to dry overnight. This process is repeated until the entire floor has been poured and allowed to cure.
Polishing and Sealing
After the terrazzo is dry, installers use a heavy-duty floor grinder to polish the surface. They start with a high level of abrasion and repeat the process using finer and finer grinding tools. When this process is complete, the floor is very smooth and even, with little to no texture. After the polishing is complete, a clear sealer is added to the surface of the floor. This sealer prevents water and other substances from permeating the surface, helping to repel stains and prolong the life of the terrazzo.
- Photo Credit Colros: Flickr.com
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