The Perfect Profile
Correct surface preparation is the key to obtaining beautiful flooring that lasts for decades. Claude Besson, from National Flooring Equipment, explains the best techniques for concrete profiling. Concrete surface profile (CSP) is a standardized measure for the roughness of a surface that has been established by the International Concrete Repair Institute (ICRI). CSP is expressed in a range of 1 to 9, with the latter representing the roughest finish possible. There are several methods to obtain the ideal CSP, which can be grouped in two broad categories - mechanical and chemical. Before starting any concrete profiling, scraping off old coatings will save time and allow the operator to limit dust and broken parts. After this step, one of the most commonly used techniques for mechanical concrete profiling is abrasion using diamond grinding to erode the surface providing progressive disintegration of the concrete, resulting in a flat and relatively uniform surface. Contractors can also use differences in heat to profile a surface, a method known as expansive pressure. Here, the surface is heated quickly using flame blasting, high-pressure water jetting, or steam blasting, causing the top to peel off. Another option is pulverization, with small particles traveling at high speed colliding against the surface. This method causes minimal damage to the surface, being undertaken most commonly by abrasive blasting, sandblasting, or shot blasting. For very rough profiles, contractors can use the impact technique, which is usually done with a bush hammer or scarifier. In this method, the substrate crumbles as a result of repeated impact by a hardened point, which causes the aggregate and cement paste to crack. Chemical reactions are used when the job site cannot accommodate large machinery and the substrate is so compromised that handheld devices are not powerful enough. Although not considered environmentally friendly, chemical treatments might be the only solution. The method involves applying a solution of water and muriatic or citric acid to the concrete with a low-pressure sprayer or a plastic sprinkling, which can remove the superficial cement paste and expose the fine aggregate. Acid treatments produce a very light profile similar to fine sandpaper. As light profiling is suited to thin coatings, this method is ideal for micro toppings that are less than 4 in (10 mm) thick. Because chemical treatments can release toxic materials, operators should wear personal protective equipment such as goggles. Contact between machinery and acid should be avoided as well to prevent corrosion. Operators should also be aware of local regulations governing safe disposal of acid and contaminated water.