Polished concrete is concrete that has been treated with a chemical densifier and ground with progressively finer grinding tools. The grinding tools are usually progressive grits of diamond grinding cup wheels and diamond polishing pads. Typically, concrete is not considered polished before 400 grit, and it is normally finished to either the 800, 1500, or 3000 grit level. Stains and dyes are often applied to enhance polished concrete as well as other options such as scoring, creating radial lines, grids, bands, borders, and other designs.
Polished concrete is considered a good sustainable design flooring option because it makes use of the materials already present. Most modern buildings are built on a concrete slab; polishing the exposed concrete eliminates the energy and material consumed by applying a floor covering. It is something to consider when building or modernizing towards a more green solution.
Polished concrete floors are low-maintenance, as they are more durable and easier to clean than many flooring options. Its relatively high coefficient of friction can make it non-slippery. Polished concrete reduces dust mite and allergen problems, and does not support mould growth. Anecdotal evidence suggests highly reflective polished concrete reduces lighting needs and improves natural lighting, but as of yet there has not been a study to confirm this. Polished concrete flooring is hard wearing and will not chip or dent like softer surfaces such as timber and mopping with warm soapy water once a week is the only maintenance required.
LEED 2009 standards contain guidelines for using polished concrete flooring to qualify for LEED credits.
New or retrofit
In simple terms, the process of polishing concrete is similar to sanding wood. Heavy-duty polishing machines, for example concrete grinder, are used to gradually grind down surfaces to the desired degree of shine and smoothness. The closest equivalent example would be polished granite or marble.
Polished concrete floor installation is categorised into two types: new floors, and retrofit floors.
New floors require less work resulting in lower costs, but there are a few things to be aware of before a new concrete floor can be polished. Firstly the slab can contain a decorative aggregate. The two most common aggregates are river stone, granite, and black basalt mix, however the aggregate can be almost anything. The finished surface of the concrete will need to be finished to a high standard to facilitate the polishing process. During the finishing phase any decorative aggregates such as seashells or car parts can be dropped into the surface of the concrete. Builder needs to be aware as early as possible if the concrete is to be polished so that the final finish is of the best quality.
Retrofit floors can be done in two ways. The existing floor slab can be cut or sanded and the natural aggregate will be the feature or a topping slab with a minimum thickness of 50 mm can be added on top of the existing slab.
Process involved in polishing concrete:
- The concrete floor is cut 3–4 times depending on the finished surface. This can be done wet or dry depend on the site situation.
- The surface is then grouted with cement to correct imperfections and fill air bubbles.
- Two more cuts are done after grouting.
- A clear liquid hardener referred to as an indensifier is then worked over the surface for about 1 hour. The indensifier will provide a glossy look to the finished floor. It will also give the floor extra strength.
- The floor is then left overnight for curing before 3 more polishing grit are done.
- Lastly the concrete surface will be sealed with a stain and block out sealer to reduce water and oil staining.
- Timing of delivery depends on the type of equipment that a contractor uses. It can be expected that a 32" grinder will average 600 square feet per hour per grit, and a large Bobcat mounted 3-headed grinder can grind 2,000 square feet per hour per grit. The Bobcat grinders have limited availability on the east and west coast.
Notable buildings with polished concrete
- Solyndra, Fremont, CA – President Obama and Governor Arnold Schwarzenegger walked on this Diacon polished concrete floor in May of 2010
- California Academy of Sciences, San Francisco, CA
- Saddleback Church Teen Center, Lake Forest, CA
- Planes of Fame Air Museum, Chino, CA
- California State University, Sacramento, CA by Pacific Decorative Concrete
- University of New Mexico Arena "The Pit" Albuquerque, New Mexico
Wikimedia Foundation. 2010.
Look at other dictionaries:
Concrete densifier — A concrete densifier is a chemical applied to a concrete surface in order to fill pores, increasing surface density. Chemical densifiers are used on polished and non polished concrete to reduce dusting and wear; on polished concrete surfaces… … Wikipedia
Concrete polishing — The art of concrete polishing is a recent innovation to the concrete industry. It is a process that was adapted from the ancient method of polishing stone.The adaption of polished concrete was first originated in the early 1990 s by an engineer… … Wikipedia
Concrete sealers — are coatings applied to concrete to protect it from corrosion. They either block the pores in the concrete to reduce absorption of water and salts or form an impermeable layer which prevents such materials from passing. Extensive research from … Wikipedia
Decorative concrete — Stamped Concrete in various patterns, highlighted with acid stain) Decorative concrete is the use of concrete as not simply a utilitarian medium for construction but as an aesthetic enhancement to a structure, while still serving its function as… … Wikipedia
Snowhill — Infobox building building name = Snowhill caption = A view of Phases 3 and 4 from St. Chad s Cathedral building type = Hotel, residential, office and retail architectural style = Postmodern structural system = location = Snow Hill Queensway,… … Wikipedia
Diamond grinding cup wheel — A single row diamond grinding cup wheel with 8 diamond segments. A diamond grinding cup wheel is a metal bonded diamond tool with diamond segments welded or cold pressed on a steel (or other metal, such as aluminum) wheel body, which usually… … Wikipedia
International Grooving & Grinding Association — (IGGA) Logo Industry Grooving, grinding, concrete pavement restorati … Wikipedia
Diamond grinding of pavement — Diamond grinding is a pavement preservation technique that corrects a variety of surface imperfections on both concrete and asphalt pavements. Most often utilized on concrete pavement, diamond grinding is typically performed in conjunction with… … Wikipedia
Strathmore (Maryland) — Strathmore is a cultural and artistic venue and institution in North Bethesda, Maryland, USA. Strathmore was founded in 1981 and consists of two venues: the Mansion and the Music Center.The Strathmore arts complex is connected to the Grosvenor… … Wikipedia
Paris Métro Line 14 — Line 14 Year opened 1998 Last extension 2007 Rolling stock MP 89 6 carriages per trainset Stations served 9 Terminal stations … Wikipedia