Revealing the beauty of concrete floors
The first stage
Determine the condition of the floor and its compatibility for the specified finish. Is the brief to polish the very top surface laitance or to grind down to reveal the aggregate stones?
The concrete may be new and completely flat, but it could equally be poorly laid or old and uneven, worn, cracked, scratched and covered in contaminants. These can all be addressed, but there needs to be acceptance that a polished concrete floor often isn’t uniform. When revealing the aggregate, the type, distribution and colour in the mix and its depth etc. can vary. Hand grinding a sample area and on bigger jobs a sample area on each individual slab, will give a good indication of the finished result.
For any evident cracks, they can be left but made stable or filled and colour matched. Again, it depends on the brief. The distressed look can be popular.
The equipment:
Levelling, flattening and smoothing the surface is addressed by mechanically grinding it. This is then followed by polishing it to the specified level of shine. The machine used may be dictated by the area size, accessibility and available power supply.
For medium to large projects:
A Terrco? Grinder & Polisher fitted with metal bonded diamond shoes, with the operator progressing from coarse to fine grades. The benefit of a multi-head, direct drive machine like Terrco, is that the diamonds cut randomly over a large surface area, resulting in flatter floors and no linear tracking marks.
When the area is flat and smooth, polishing can begin with resin diamonds, again working up through a series of steps from the coarsest to the finer grades. Wet polishing increases diamond life and produces even better results. A high gloss finish isn’t recommended for high traffic areas, as it can be slippery when wet.
For small to medium projects:
An STG450 fitted with a heavy-duty drive plate to grind the area flat. This would be followed by the SFD (Surface Finishing Diamond Pad) system from the coarsest grit, up to the finer grades to the desired finish.; matt, sheen or high gloss.
In both cases, after grinding, but before polishing, a liquid chemical hardener or densifier can be applied to the surface to form a hard, crystalline structure. If required a multitude of finishing seals are available.