How Geoshine™ creates a brilliant polished concrete floor

The Geoshine™ process can begin 7-28 days after a concrete slab has been laid and fully cured (read more about what this means). It encompasses a series of grinding, sealing and polishing steps carried out in two stages.

Stage 1: Grinding

In a new building, the grinding stage must be completed before any construction work begins on the slab. In a renovation, the grinding is done before any substantial carpentry work (e.g. skirting, joinery).

It is at this stage you decide how much of the aggregate in the concrete you want exposed: none (just a surface polish); partial exposure (a salt-and-pepper look); or full exposure (as much stone showing as possible).

Geocrete includes up to three millimetres (3mm) in its standard grinding process; you can have up to 5mm at extra cost. We use a four-head planetary grinder with metal bonded diamond heads to carry out three grinding cuts: coarse, medium and fine.

  1. Coarse – 30-grit diamond segments are used to grind 3mm off the floor to expose the stones.
  2. Medium – 60-grit diamond segments remove the scratches from the 30-grit segments.

Before the third grind, a clear acrylic polymer is applied to the floor as a grout. Its purpose is to fill in holes, cracks or unevenness caused by the coarse and medium grinds.

  1. Fine – 120-grit diamond segments are run over the floor, which combines concrete dust with the grout and pushes it into the holes and cracks. It also removes the 60-grit scratches.

In the final step in this stage we apply the first in a series of premium ‘surface densifiers’. This is a liquid chemical that reacts with some of the 15-20% of unconverted calcium hydroxide in the concrete and turns it into the much harder calcium silicate hydrate (CSH). CSH is what bonds with the aggregate to form concrete, giving it strength and hardness. The densifier is absorbed into the floor, continuing the chemical reaction.

It takes 2-3 days to complete stage 1 for an area of 200m2.

Stage 2: Polishing

This stage can start as soon as one day after the completion of stage 1, depending on your construction process. Stage 2 takes from 3-7 days for an area of 200m2.

In new construction, Geocrete will return after the plaster is hung. If access could become limited, some wall placements may need to be delayed. Other delays will also be needed to skirting, joinery, tiles, stairs and internal door frames until polishing is complete. The requirements are similar for a renovation.

The Geoshine™ polishing process can produce three different levels of sheen: matt, satin or high gloss. High gloss is the most requested surface finish.

  1. The floor is regrouted and densifier is applied over the surface and allowed to chemically react overnight.
  2. The next day, another thin coat of densifier is applied. While still wet, the grinding machine is used to polish the floor with a 50-grit polishing pad.
  3. Another coat of densifier is applied, allowed to dry and then polished. This continues for several applications, using finer polishing pads each time – 100, 200, 400, 800, 1500 and 3000 grit.
  4. A penetrating sealer is applied twice and allowed to dry. This sealer provides the final level of stain resistance; it can withstand red wine or coffee for up to seven hours without causing a permanent stain.
  5. A final buff removes the sealer residue and gives the floor its signature Geoshine™!

During further construction work, if protection is put on the floor only fabric painters’ drop-sheets should be used. These allow the concrete to ‘breathe’.

The strength of Geoshine™

You now have a brilliant, beautiful, incredibly hard polished concrete floor that will retain its lustre for 10 years. After 10 years, we recommend a repolish, buff and reseal.

The strength of Geoshine™ lies in its sequence, choice and application of densifying chemicals and the sequence and choice of grinding and polishing pads. We use the highest quality densifiers, which cost twice the price of standard densifiers, and the best grinding and polishing equipment available, regardless of the manufacturer.