What Is Terrazzo?
Many people question what is terrazzo? To answer that question, terrazzo is capable of forming many unique finishes. If to sum up terrazzo in one sentence, terrazzo is described as a composite material, poured in place or prefabricated for precast terrazzo which is used for flooring, base, walls, stair treads, countertops, and other custom products. Terrazzo consists of chips of marble, granite, quartz, glass, shell or other suitable materials. Terrazzo uses either a cement or epoxy matrix as the binder.
Metal strips divide sections, make color transitions, design decorative patterns or logos and allow for movement or crack mitigation. Divider strips are made from aluminum (epoxy terrazzo only), zinc, brass or plastic but never stainless steel.
Installation – Epoxy Terrazzo
Epoxy terrazzo is less labor-intensive and doesn’t require many of the skills that cementitious terrazzo does. Epoxy terrazzo is a mixture of a Part A (Base color) and a Part B (Hardener). The typical ratio is 5:1. The part A & B are mixed together with filler powder (marble dust) and the aggregate. The epoxy and aggregate mix is then poured on the floor and placed at the required height with hand trowels then closed with a power trowel to flatten and tighten up the aggregate. It is the practice of some installers to also seed the floor prior to power troweling. Epoxy installed in the proper ambient conditions can be ground within 24 hours.
Grinding, Grouting, And Polishing Stages
Grinding of both cementitious and epoxy terrazzo are relatively the same procedure with the exception being the process for the initial rough grinding. Epoxy terrazzo rough grinding is done dry with vacuum systems to collect the grinding dust. In contrast, cement terrazzo is wet-ground so a grinding slurry is created. After the floor is rough ground until the metal or plastic divider strips are exposed and the aggregate is uniformly exposed, both systems are grouted. In this step, an installer matches binder material to fill any pin holes or voids. After proper curing of the grout, the floor is then polished. Typically polishing is done wet in both systems to the required finish level ranging from 120 grit up to 3000 grit. Both cementitious and epoxy systems are thoroughly cleaned, dried and treated with a minimum of 2 coats of the appropriate sealer.