What are Polished Concrete Floors?
A polished concrete floor is a regular concrete floor where the surface has been ground by a series of diamond tools designed to mechanically refine the concrete surface so that it produces consistent gloss, clarity and shine. The polishing process is similar to the one used for granite and marble.
A concrete floor typically needs to be ground 7-10 times, reaching at least an 800 grit finish, to achieve a polished surface. The surface appearance of a polished concrete floor is created through the diamond polishing process and not by the use of a surface coating or sealer. There is no surface material to peel, chip or crack. This allows the concrete slab to breathe and maintain a healthy state.
Polishing concrete creates a surface with a teflon-like resistance to marking and dirt which makes them easy to maintain and keep clean. This is one of the primary advantages over other concrete flooring options.
A self-levelling polished concrete topping is another type of polished concrete flooring. Ardex PC-T is a well known concrete topping that is designed to be polished. Concrete toppings, otherwise known as polishable overlays are typically used when a concrete floor has been damaged too badly to be polished. It may also be poured onto wood floors to create a concrete floor. Once the topping has been poured and reached the minimum curing time, it will be diamond polished like regular concrete.
Polished concrete floors are available in different levels of sheen. The first level is an 800 grit finish, it has the lowest level of gloss, clarity and shine. It’s commonly used for industrial floors because it has the lowest cost while still providing a like-new appearance.
The 1500 grit finish is the mid level and can be found everywhere from industrial floors to art galleries. It provides improved gloss, clarity and shine over the 800 grit for a nicer aesthetic appearance.
The 3000 grit finish is the highest polish level providing excellent gloss, clarity and shine. It is excellent for high traffic applications like retail stores, offices, universities and other institutions that need to maintain a professional image.
Can any Concrete Floor be Polished?
Any existing concrete floor where the cementitious portion (cement paste/gel) of the concrete retains its integrity can be polished. If the concrete slab has been compromised by chemical contamination, or other factors, the floor will not retain its polished surface for an acceptable length of time.
Concrete floors that have integrity but have been physically damaged may also be unsuitable for polishing because the final finish may be blotchy and inconsistent. The expectations of the customers would determine whether or not this second scenario would be suitable for polished concrete flooring.
The general rule for determining if a concrete floor can be polished:
- It should be free of oil and other chemical contamination
- There should be minimal surface damage
- The floor should not have a large number of repairs or trenches
Concrete floors that were covered with carpet, tile or wood floors can normally be polished without issue, after an adhesive removal grinding process. Concrete floors that had VCT tile will retain a checkered board pattern in the floor but may be polished if the customer deems it acceptable.
A professional concrete polishing process begins with an aggressive diamond tool that removes the surface concrete and exposes a clean, new layer. It’s important to remove any surface contamination or soiled concrete.
All of the proceeding grinding steps are finer grits that progressively hone and polish the surface. It is a best practice to use a lithium silicate densifier with the polishing process to enhance the durability of the surface.
The hardness or MPa of the concrete surface will predominantly determine the durability and life of the floor.
What is the cost of a Polished Concrete Floor?
The cost of a polished concrete floor will vary based on the following criteria:
- The size of the project
- The condition of the concrete floor
- If the area is one open space or multiple spaces
- Access to job site (week days, nights, weekends)
- The level of polish 800 grit – 3000 grit
- The amount of repair work and joints to fill
- Standard or terrazzo look
- Edge polishing
A general cost guideline for polished concrete floors:
- Industrial floors $1.95 to $3.50 per square foot
- Commercial floors $2.50 to $8.50 per square foot
Every concrete surface needs to be individually assessed to receive an accurate quote.
Are Polished Concrete Floors Slippery?
No, polished concrete floors are not slippery. They exceed the minimum dynamic coefficient of friction level (ANSI A137.1) at all grits (800, 1500, and 3000 grit). Architects, designers and plant managers can find detailed information about slip resistance (DCOF) on the Concrete Polishing Council’s website. Slip resistance problems for a polished concrete flooring system will primarily be caused by poor maintenance of the floor. Poor maintenance can cause any flooring type to become unsafe so it’s important to have a structured program in place. Stain guards and floor coatings can decrease the slip resistance of a polished concrete floor so test data should be consulted before use.
What is the Best Finish for a Concrete Floor?
The best finish for a concrete floor is determined by the requirements of the business or organization. Here are some general guidelines when considering flooring options:
- Polished concrete is best for high traffic offices, retail, warehouses and dry manufacturing. It provides a low maintenance, durable surface with the lowest cost.
- A resinous floor coating like epoxy, polyurethane or polyaspartic is best for businesses that handle chemicals, oils, or liquids.
Concrete floors need to be completed sealed off from chemical contamination because they will absorb chemicals. Once they are absorbed they cannot be removed and may leach into the environment.
What are the Advantages of Polished Concrete Floors?
- a beautiful but understated appearance allows merchandise or other elements in the room to remain the focus
- extremely durable, will stand up to high traffic environments
- existing concrete floors can be polished negating the need to bring in new flooring
- teflon-like polished surface resists marking and dirt making it easy to clean and maintain
- exceeds the slip resistance minimum dynamic coefficient of friction (ANSI A137.1)
- environmentally friendly and VOC free
- low cost to install and maintain
- increases ambient light up to 30% through reflection
- no coating to scratch, chip or peel
What are the Disadvantages of Polished Concrete?
- Concrete is porous and will absorb liquids which may stain or damage the floor. It is not suitable for environments that are regularly exposed to liquids.
- Concrete is susceptible to acidic substances. It should not be used in areas with regular exposure to any type of acidic substances including fruits and vegetables, beer and wine, chemicals, oils, and acidic cleaners.
- It does not have a consistent, homogenous finish. You will see variations in the amount of fine and large aggregate on the surface. The colour may also vary from region to region.
Call us for a free concrete polishing quote, (647) 544-4143.
Polished Concrete 1 Inc. is a concrete polishing and epoxy flooring contractor serving the greater Toronto area and Mississauga, Brampton, Vaughan, Oakville, Burlington and more.