For this project were were asked to polish the concrete floor of a newly constructed barn in Newtown CT. The owners wanted a dark grey polished slab with a satin finish rather than a very high shine.
We started by grinding the floor with 30/40 grit metal diamond tooling. The slab was very soft (see note) and we were able to expose aggregate very quickly.
Due to the softness of the surface we did not think it was a good candidate for a full polish so we decided to grind to 80/100 grit and then add the color stain.
We stain our floors with Elite Crete Hydra-Stone. The color is sprayed onto the surface in several coats to give the same effect as an acid stain but without the mess and spell.
After staining we coated the floor with Elite Crete PT-1 clear epoxy. Epoxy is a self leveling material that dries to a deep, high gloss. The next day the slab was sanded and top coated with Elite Crete AUS-V, a durable aliphatic urethane which dries to a satin eggshell finish.
Note. Here in CT we often come across soft concrete slabs. In my opinion, this is caused by contractors working the surface too early. By not allowing enough time for the water to react with the cement to develop hardened concrete, the bleed water is forced back into the surface resulting in a weak, permeable and soft top surface. At its most extreme the top surface of the slab will comprise of concrete dust. Dusting is more common in winter when cure times are lengthy due to temperature.
