This involves polishing, not grinding away, the top layer of the surface paste. Typical of the industrial setting, this finish reveals all the variations in colour and texture. No aggregate is exposed, just a sandy and often uneven finish. Because the imperfections aren’t being ground out, it is crucial the concrete placement is smooth and has an even surface. It is still smooth to touch and hardeners are applied, however it will be more susceptible to staining. The bronze polished concrete floor can be brought up to a matt or high gloss.
First step is a deep grind which reveals the variations in sand, gravel and aggregate underneath the sandy layer. Giving a Terrazzo like look. Hardener is then applied. After the first grind, progressively smaller diamond disks are used to remove the scratches made by the previous grind. Floor is treated with an impregnating seal after the final grind. The silver finish is left with a matte or satin look.
For a Gold finish, the initial grinding and polishing step is finer. Because the grind is not as deep into the concrete, less aggregate is exposed. This gives a smooth, salt and pepper polished concrete look with a highly reflective surface. Typically, 1 mm of the surface is ground away, so there is no room for error or variations in levels. This finish can only be achieved if the concrete has been power floated and is completely smooth before the grinding commences.
The platinum finish gives the floor the best characteristics and is often opted for in a domestic situation. It involves more grinding steps than the other options, bringing the floor up to a 3,000 grit. The result is an unbeatably durable floor, with a highly reflective finish. Between 2 mm and 3 mm are ground off from the surface. The polishing process closes the pores in the concrete, facilitating its resistance to staining. The more it is polished, the more pores are closed. Platinum finish is generally considered to be the ‘Rolls Royce’ of polished concrete floors.