Frequently Asked Questions
Ground and Polished Concrete Floors
Q. What is Concrete Grinding and Polishing?
When grinding concrete floors, the weaker concrete outer skin is removed and the stronger and harder concrete surface is exposed. Concrete floor grinding and polishing is created by mechanical processing of the concrete surface by means of grinding and refining the surface using diamond-encrusted abrasive tools until a desired finish is achieved.
This process takes some time and only a qualified specialist in concrete grinding and polishing, such as World of Decorative Concrete, should ideally be appointed to install a ground and polished concrete floor.
Q. Can anyone grind and polish concrete?
To achieve the standard and quality of the concrete grinding and polishing to the standard displayed on World of Decorative Concrete’s webpages, full knowledge of the process, of concrete and the proper execution of the process, along with the best quality machines and grinding tools, are required.
There may be a number of companies and people in the grinding and polishing industry. However, it’s always a fair recommendation to inspect actual work done and to obtain references from companies/individuals who made use of these companies. World of Decorative Concrete’s products can be viewed across most of southern Africa. One of the greatest achievements has been the successful completion of 63 000 m2 concrete flooring and the manufacturing of all the hard landscape items at the Moses Mabhida World Cup Soccer Stadium in Durban.
Q. Is Ground and Polished Concrete slippery?
When ground and polished concrete floors are been kept clean and dry, these concrete floors are generally no more slippery than normal plain power floated concrete floors. In fact, it tends to be less slippery than waxed linoleum floors, polished marble and epoxy floors.
According to the ADA, OSHA and ASTM guidelines, ground and polished floor surfaces shall be considered slip resistant if the measured static coefficient of friction is a minimum of 0.5 when tested in accordance with either ASTM C-1028 ( field laboratory test) or ASTM D-2047 (laboratory test) methods. The results were as follow:
Dry Floor: High gloss polished floor finished with a 3000 grit resin diamond- 0.7 averages of multiple readings, meaning it EXCEEDS the OSHA standards by 40%.
Wet Floor: High gloss polished floor finished with a 3000 grit resin diamond- 0.61 averages of multiple readings, meaning it EXCEEDS the OSHA standards by 22%.
There are other ways of finishing of a ground and polished concrete surface by means of a non-slip sealer and/or by applying WODC’s special surface technique.
When used externally and/or if a client wants that extra peace of mind regarding safety, please consult with World of Decorative Concrete.
Q. What does it take to produce a quality Ground and Polished Concrete floor?
World of Decorative Concrete uses high-tech machinery, specialized diamond tools and employs unique techniques in which we are thoroughly experienced. This superior application, special process and knowledge of concrete has been fine-tuned to produce magnificent concrete floors, unequalled in the industry. It is important to mention that quality Ground and Polished Concrete floors are not done by just exposing the aggregate in the concrete and then applying a sealer. This finished product will never achieve the brilliance, nor be as long-lasting as a true Ground and Polished Concrete floor.
Q. Will the end product always deliver the same result?
The actual grinding and polishing process determines only 20% of the final outcome of the floor. The other 80% is determined by the placing of the concrete and also the type of concrete used.
It is very important for the client to understand the look and feel required for the floor. This is influenced by the type of product chosen, as well as the type and method of the grinding and polishing process. Artevia Polished, supplied by Lafarge, has a different look than the Terra Floor Overlay. The process and method of application and the materials are different for these two polished concrete systems.
It is very important that the client pays close attention to the following:
Choice of concrete
The client should consult with World of Decorative Concrete before commencing with a project. World of Decorative Concrete will specify the materials and processes in order to meet the client’s expectations.
Placing of concrete
This aspect is extremely important. In most cases where disappointment occurs with the final result, the placing of the concrete was the underlying cause for the unsatisfactory end result.
To guarantee an acceptable end result, the concrete mix and placing of the concrete must be strictly controlled and high-level supervision must be maintained throughout the process. Contact World of Decorative Concrete in this regard.
Q. Can a Terra Floor system be installed and ground and polished by anyone?
The answer is a definite NO! This product was self-engineered by World of Decorative Concrete. Only our employed, well trained staff or well-trained sub-contractors, approved by us, are allowed to install, grind and polish a Terra Floor.
Q. How much dust is generated by the grinding and polishing process?
World of Decorative Concrete uses high-tech machinery to do a dry grinding process, which generates dust, especially during edge grinding. Due to the fact that normally we are working simultaneously with other trades at the same time, dust can be a problem for them. We use industrial vacuum machines as far as possible and/or lightly wet the surface during the grinding process to control the dust levels to the best of our ability
Q. Will the floor be super flat and what about levels?
Flatness of a Ground and Polished Terra Floor:
The substrate below will determine the flatness of the floor. Due to the fact that a Terra Floor is only a 12-15mm overlay and that clients want to see a good aggregate distribution, variation in the flatness of the floor may occur. The average variation is +- 5mm over a length of 3m.
Flatness of a Ground and Polished Artevia Polished Floor:
Clients usually choose their Artevia Polished Floor based on concrete samples which are normally manufactured under controlled conditions and not based on pump mixes. Where concrete is pumped on site, the aggregate can be up to 20% less than in the sample supplied. In small or difficult areas where it is not financially viable to pump the concrete, and where one needs to discharge and place the concrete by hand, the end result to achieve a flat floor can be difficult. The average variation is +- 5mm over a length of 3m.
Levels on site:
For both a Terra Floor and an Artevia Polished Floor, it is the responsibility of the main contractor to issue World of Decorative Concrete with the final floor levels. Where levels are a problem on site, it is very important to consult with all parties involved, prior to the placement of a Terra Floor or an Artevia Polished Floor, to resolve matters.
It is not the responsibility of World of Decorative Concrete to address levels that was ignored during the initial concrete casting process by others.
Please note that World of Decorative Concrete only removes a maximum of 4mm-5mm from the top surface of the concrete during the 7 stage grinding and polishing process.
Q. What are the benefits of Polished Concrete?
Beautiful – Polished Concrete have a luxurious natural look, competitive with Natural Stone flooring.
Long lasting solution – No sealers that can wear off are used.
Coating free – Because there are no coatings to cure, the floor is ready for immediate use.
Needs minimal maintenance – Just a sweep and mop! No strippers and waxes are used.
“Green” – A significant number of LEED points are gained by using Polished Concrete.
Highly durable – Our densifier/sealer hardens and dustproofs the concrete.
Tough – Polished Concrete is not damaged by foot traffic, forklift tires, vehicles, pallets, etc.
Safe – Wet or dry, it meets or exceeds all OSHA slip resistance standards.
Yours in ‘Concrete with Soul’
Go to our Contact Us page for more information and to make contact with our concrete specialists.