Diamond Polishing and Grinding
Dimond polishing and customised concrete polishing give a high gloss finish to any surface. From a Woolworths entrance, a boardroom stone finish to the highest spec distribution centre, CHC-SA pour, and finish to the specification of the client. As integral members of the value chain, our ability to deliver on multiple levels within that value chain and maintain our product over time gives us the ability to deliver quality and price at competitive rates.
The success of the end result, is of course directly proportional to the successful planning and placing of the concrete floor. In order to achieve a good result, there is a significant amount of planning required:
CHC-SA will be able to assist with the following:
- Selection of the most suitable concrete mix. (Samples of the proposed concrete to be prepared. Different materials / aggregates = different result)
- We suggest 35Mpa / 40Mpa mix with 600g per m3 of micro fibre
- The higher the strength / Mpa of the concrete mix, the better it will perform over time.
- Floor design and saw cut layout.
- Saw cuts to be positioned correctly
- We recommend the use of some mesh in the floor, continuous through the joints (as per TR 34 attached). This helps to restrain the opening of the joints.
- Some facilities require a floor to falls. There has been much debate over the years in this regard. We suggest to rather have a level floor (only to slope around the drains)
Ideally, we prefer to place the concrete ourselves.
Levels of Concrete Polishing
How to achieve different levels of sheen on a polished floors and a better understanding of Polished Concrete:
At a level 3 polish, your concrete floors will really begin to shine and clearly reflect side and overhead lighting.
Depending on the diamond grit you use to polish a concrete floor, you can achieve different ranges of polish and different levels of sheen, from matte to a glassy mirror-like finish. These ranges are typically categorized in levels ranging from 1 through 4. For coarse grinding, you’ll generally start out using diamonds embedded in a metal matrix. As you begin to polish the floor in successive passes, you’ll typically switch to finer diamond abrasives bonded in a plastic or resinous matrix to achieve higher degrees of shine. Here are the four levels of polishing and the degree of shine you can expect to achieve at each level. (Source: Bob Harris’ Guide to Polished Concrete)
Level 1 polish A level 1 polish usually can be obtained by stopping at the 100-grit resin bond. When you look directly down at the floor, it will appear somewhat hazy with little if any clarity or reflection.
Level 2 polish A level 2 polish is obtained by stopping at the 400-grit resin bond, producing a low-sheen finish. When you look directly down at the finished floor and at a distance of roughly 100 feet, you can start to see a slight overhead reflection. This grit level produces a low-luster matte finish.
Level 3 polish A level 3 polish is achieved by going up to an 800-grit diamond abrasive. The surface will have a much higher sheen than that of level 2 finish, and you’ll start to see good light reflectivity. At a distance of 10m – 15m, the floor will clearly reflect side and overhead lighting.
Level 4 polish This level of polish produces a high degree of shine, so that when standing directly over the surface, you can see your reflection with total clarity. Also, the floor appears to be wet when viewed from different vantage points. A level 4 polish is obtained by going up to a 3,000-grit resin-bond diamond or by burnishing the floor with a high-speed burnisher outfitted with specialty buffing pads.
Measuring the gloss level Once you have completed the entire polishing process, you’ll be left with a beautiful, shiny surface. But how do you accurately assess the degree of shine, other than by simply visually inspecting the amount of light reflectivity or clarity of the polished surface? Today, specifications for polished concrete are now including specified gloss readings, determined using gloss meters (see table). Gloss values express the degree of reflection when light hits the concrete floor surface, and range from 20 to 30 (low gloss) to 70 to 80 (high gloss). For example, a gloss value around 30 will generally produce a low-satin sheen while a value of 80 will produce a very high shine, especially after high-speed burnishing.
Gloss Level Table
Grit – 100
Sheen Level – Dull or matte look
Gloss Reading – N/A
Appearance – Floor has little if any reflectivity.
Grit – 400
Sheen Level – Low sheen
Gloss Reading – 40 – 50
Appearance – From a distance, floor will start to reflect images from the side. Floor has a whitish or cloudy appearance.
Grit – 800
Sheen Level – Shiny look that is slightly cloudy
Gloss Reading – 50 – 60
Appearance – At a distance of 10m to 15 m, the floor reflects from side to side. Floor starts to shine, but has a slightly fuzzy appearance.
Grit – 1,500 – 3,000
Sheen Level – High sheen with clarity
Gloss Reading – 60 – 80
Appearance – Looking straight down on the floor, it clearly reflects overhead and side lighting. The floor is very shiny and looks wet from a distance.