Grinding, More Grinding

Much of the terrazzo restoration process is centered around grinding. Not only is grinding an integral part of removing surface layers of terrazzo, but it is also necessary for achieving the finished polish that terrazzo is famous for. While it may seem odd, terrazzo grinding often ranges from 3 to 12 steps, where initial layers are quickly and deeply stripped off and subsequent applications serve to polish and smooth out the newly excavated layer. The way grinding works is by essentially cutting off top layers (surface coat, stone, sealant) to reveal a new layer beneath. With most terrazzo floors easily reaching an inch thick or more, shaving off a quarter of an inch will reveal an all-new floor by cutting through the worn layers to a new flat surface.

Hole Filling

If there are any holes or chips that extend below the newly revealed surface, then it may be necessary to create a patch for the damaged area. To do so, people will likely drill into the hole a small amount to create a rough surface for the patch to dig into, then they will attempt to match the original coating and stones used to create a seamless mixture that will fill the area. The hole is overfilled and then ground down and polished in with concrete diamond tooling to make as natural a patch as possible. When done correctly, there should be little-to-no evidence of a hole ever existing when the patch is completed. It is important to note that holes are best filled after the grinding, but before the final polishing, so that the floor can be easily matched and blended with the most accuracy.

Final Polish

After the numerous rounds of grinding and any hole filling, all that will be left for your floors is to polish them up. There are a few ways to polish with terrazzo floor polishing tools during terrazzo restoration, the most common way features an acid powder distributed across the floor, which is then mixed with water and polished by a specialized machine. This method effectively ingrains the polish onto the surface of the terrazzo floor below and keeps the surface smooth and level. Even though the polishing may seem like a single step, it is not uncommon to see 20 passes of the polisher across the floor to ensure a long-lasting shiny surface. At the end of the restoration, the terrazzo should be highly shiny, a clear indication that the restoration will almost certainly last for years to come.