Here below are a few common questions and answers related to polished concrete. For more specific information please check our Technical page. Please keep in mind that the polishing process, equipment used and necessary phases vary not only from project to project, but also by company, client requests, products manufacturers, diamond tooling, and more.
Q: Can all concrete slabs be diamond polished?
A: No. Most concrete ever poured was not meant or, let's say engineered for diamond polishing. In most cases when diamond polishing we are looking for concrete that is in "sound" conditions, meaning concrete that can maintain its structural strength and integrity during the grinding and polishing operation. Only in a few cases we encountered floors that could not be directly polished. In such a situation, if strengthening products are not enough, a cement overlay can be applied (after structural repairs are performed) or a new concrete slab can be poured prior to polishing. Thanks to new technology we can now repair moving cracks, control joints and expansion joints during the polishing operations.
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Q: Is polished concrete slippery?
A: No. Because of the invisible micro-scratch pattern left by the diamonds, polished concrete surfaces are extremely safe when dry. When a floor is wet (that's valid for any hard surface such as ceramic tiles, epoxy coatings, linoleum floors, hardwood, laminate, VCT...) it can become more slippery. In premises open to the public it is important to use "wet floor" signs to make users aware of the changed conditions, and possibly temporarily close wet areas to traffic. Since the California building code it is not specific on the parameters that make a floor "slip safe" but only states: " Floors and ground surfaces shall be stable, firm and slip resistant" (CA Building Code section 11B-302.1) it is difficult to determine if a floor is safe or not. The ANSI (American National Standard Institute) established some guidelines on what parameters to consider when determining slipperiness of floors, which in general depends not only on the floors, but also on the method of drainage, the shoes worn by users and other factors. In other words, the same highly reflective polished floor may be safe for a person wearing threaded sole shoes but not safe for a user with smooth sole shoes. ANSI also establishes the coefficient of 0.42 as a minimum safety standard for wet floors. A measurement can be performed with electronic and/or mechanic instruments to determine the specific coefficient of slipperiness on a specific floor.
Q: Does standard concrete cracks?
A: Yes. Portland cement based concrete is susceptible to cracking because it tends to shrink while curing. The curing is the chemical process that happens in the 4 weeks after concrete is poured and that allows concrete to gain strength. Concrete is a peculiar material that tends to increase its strength when compressed and becomes weaker when stretched. The internal forces developed in concrete when shrinking are causing points of weakness in the slab, which ultimately can become cracks. The best way to address the cracking is to install “control joints”, which are grooves or cuts every so many feet. These grooves are installed as soon as it is possible to walk on freshly poured concrete. They cause the concrete to become weak right in the bottom of the groove, and that’s where the crack will appear, but it is hidden from sight. In this way, control joints do not prevent cracking, only allow for cracking to happen in places where it can be hidden from sight
Q: Is there any concrete that will not crack?
A: Yes. A new type of concrete has been recently developed (Type K concrete). This concrete mix contains an additive that transform the concrete from a shrinking material into an expanding material. When this additive (CTS Komponent) is added to standard mix in conjunction with steel reinforcement or reinforcement fiber, the expansion in the concrete is transformed in compression force, which ultimately makes the concrete crack resistant. With Type K concrete control joints are installed every 100 feet, making most residential floors free from control joints. Keep in mind that cracking can always happen on concrete slabs of all kind, especially when the substrate moves, shifts and swells.
Q: Is all polished concrete high sheen?
A: No. Whenever a lower sheen/reflectivity is desired the polishing process can be stopped at a lower grit. This will not affect the performance and durability of the floor surface, but higher reflective surfaces are smoother and a bit easier to clean. The lower reflectivity finish (Honed Finish), usually obtained around 100 grit, produces a matte or satin look, and the light will still reflect, but not as mirror image.
Q: Does polished concrete easily scratches?
A: No. Because of the hardening produced by the diamond abrasion, Polished Concrete and Polished Cement are extremely resistant to scratching from walking traffic. Diamond polished floors are also mold and dust resistant, and can be easily sanitized, cleaned and maintained. As for any floor surface, care need to be given not to gauge the surface with heavy, pointy objects, which could cause a damage.
Q: Does polished concrete require maintenance?
A: Yes. As any other floor, polished concrete will require a certain amount of maintenance. High traffic floors (restaurants, retail centers, public buildings…) will require maintenance more frequently than residential floors. The biggest advantage of Polished Concrete and Cement surfaces is that the maintenance is very quick and more cost effective than for any other floor. On residential surfaces diamond polished floors may require a maintenance intervention as little as 5 years. The standard maintenance operation consists of re-application of protective sealer and buffing/burnishing.
Q: Does diamond polished concrete/cement require a protective sealer
A: Yes. Concrete is a very porous material, and when not protected with a topical sealer can be permanently stained. Polished concrete is a much denser surface than standard concrete, but still requires protection. A clear protective sealer offers a window of time to allow for cleaning of spills. We recommend cleaning spills as soon as possible, as when colored liquids are allowed to puddle for prolonged time, they can produce stains or discolorations. In kitchen areas we recommend using mats to prevent oil spillage near stoves. Unlike water based liquids, oil penetrates concrete much faster, and is very difficult to remove, if even possible.
Q: Is polished concrete installation messy?
A: No. In most cases polished concrete can be installed "dry", meaning that wetting the floor is not necessary ,so there will not be splattering of sludge! During the machining of the surface, dust control equipment is used to abate the airborne particulates. As it proceeds, the floor machine leaves a fine layer of grindings behind, which are removed at every pass by vacuuming. We recommend masking cabinets and other fixtures that cannot be removed before the flooring work, and that must be protected. Residual fine dust typically can be easily removed from flat large surfaces (walls, windows, ceilings...) with standard cleaning supplies. Please keep in mind that on each project a certain amount of residual dust has to be expected.
Q: Is polished concrete installation noisy?
A: A little bit. The amount of noise varies depending on environmental conditions, equipment used, and phases, but it is always within the OSHA regulations and allowed parameters. Work areas can be accessed without use of ear protections. There are mainly three noise components to this process: the floor machine, the dust control unit, and the abrasion of the diamonds on the concrete. Besides through the air, sound can also travel through the concrete slab itself, sometimes making the operation noticeable in other adjacent areas, even if they are isolated from the work space.