Polished Concrete Takes the LEED

By Jim Cuviello

Over the last year I have noted a tremendous increase in the number of architects and designers that are specifying polished concrete as a finished floor surface specifically based on the “green” and sustainable qualities of the new generation of polishing products.  It is clear that polished concrete can help achieve Leadership in Energy and Environmental Design, (LEED) points in every category and that it is the only flooring option that can be renewed on site. There is no other flooring on the market that beats processed and polished concrete based on an assessment of eco-responsible and sustainable attributes, and in this article I will explain how I can say that.

Polished concrete starts with the processing of the concrete surface, the act of changing an existing concrete surface by means of a mechanical process that involves cutting and/or refining the surface to a desired finish.  Polished concrete is one of many end results in the processing of the concrete surface by mechanical refinement through the use of multiple abrasives that are measured in grits (much like sand paper for woodworking).  Grits are applied from roughest to finest and each girt density refines the concrete surface in preparation for the ultimate surface finish we want to create. When “properly” processing concrete to a achieve a fully polished finish, one that has clarity of reflection and durability, a contractor will use six to nine different grits depending on many factors.  During the process a densifier is applied that creates a crystalline structure within the pores of the concrete to make it denser, thereby increasing the concrete stain resistance. The densifier also fills is micro surface imperfections making the surface more uniform and helping us attain clarity of reflection and durability we ultimately want to see.

Once we are finished we have a beautiful, durable and efficient floor surface that eliminates the need for carpets, wood, tile and other flooring materials that require expensive replacement, maintenance and use of harsh cleaning chemicals. The natural concrete floor provides long-lasting beauty and ease of maintenance as additional environmental benefits.

Concrete processing has been in use for a slightly more than a decade.  It was first used as a matter of function in warehouses to eliminate dusting, increase lighting, reduce ware on equipment and to create a permanent, low maintenance, coating free flooring solution.  Advances in concrete polishing technology have allowed contractors the ability to add color, decorative saw cuts, specialty aggregate that latter gets exposed by grinding and then there is the engraving, sand blasting and etching of the concrete surface.  As a result of these advances the process of polishing is now being promoted as a flooring solution to other markets such as retail, restaurants, schools and office buildings.  The end result is a functional astatically pleasing flooring solution.

Why Concrete Processing is now LEED compliant:

There are three components that make concrete processing and polishing green and sustainable – the concrete itself, the process of polishing and the final floor finish.

Concrete is primarily made from natural materials, but can incorporate recycled material such as recycled glass or fly ash.  Even the concrete itself can be recycled and then used in other projects.  Concrete is extremely durable, the ingredients for making concrete are readily available, obtaining many of its ingredients does not cause any permanent environmental harm and there is no toxic off gassing.  Concrete also has the ability to absorb, store, and later release significant amounts of heat better than many other flooring materials.

As I mentioned earlier, a polished concrete floor system is the only flooring currently on the market that can be renewed on site.  All products used for installation fall well within VOC limits.  The installation process can be done either wet (which CPm editor in chief Craig Walton advocated in the last issue) or a combination of wet and dry, either method will yield acceptable indoor air quality limits.  

ENERGY & ATMOSPHERE

Optimized Energy Performance

The concrete polishing process does not affect the thermal mass of the concrete floor.  This credit can be identified because the aesthetic beauty and ease of maintenance of the polished concrete surface does help in the decision to select concrete as the primary floor substrate.  Thermal mass is a property that enables building materials to absorb, store, and later release significant amounts of heat. These materials absorb energy slowly and hold it for much longer periods of time than do other less dense flooring materials. This characteristic helps offset heat costs and reduces spikes in the heating and cooling requirements.  

Additional credits can be obtained because the increased reflectivity of the floors surface increases the effectiveness of installed overhead lighting.  Also, the polished concrete requires less maintenance over other flooring materials like VCT or carpet.   As a result the energy needed to run maintenance equipment and the energy used for lighting that is needed for night cleaning is eliminated.

MATERIALS & RESOURCES

Building Reuse
Concrete polishing rehabilitates and/or enhances “existing” concrete floors.  This eliminates the need to have other types flooring materials put through an energy draining manufacturing process and the need to use fossil fuel to transport flooring material to a job site.

Recycled Content
Like the optimized energy performance credit it is the concrete that earns the credit and not the polishing process.  The use of recycled content in the concrete such as fly ash and glass will help gain credits in this category.  Items such as glass can be used as a decorative enhancement when ground to exposed and polished.

Regional Material
As the popularity of concrete polishing continues to increase it is now probable to find a certified concrete polishing contractor within a 500-mile radius of any geographic region.  Items used in the polishing process are collected and prepared before being taken to the job site and I most cases the elements needed to make concrete can also obtained within that same 500-mile radius.  

INDOOR ENVIRONMENTAL QUALITY

Construction IEQ Management Plan – During Construction
The concrete polishing process can be done either wet or in a combination of wet and dry.  In both situations when the polishing process is properly done air quality fall within expectable limits.

Low Emitting Materials – Adhesives and Sealants
The concrete polishing process uses solvent free, non-toxic chemicals that exceed expectable limits VOC limits.

Mold Prevention
The polished concrete surface does not hold water like other flooring materials such as carpet and is easily maintained with cleaners to prevent mold.

INNOVATION AND DESIGN PROCESS

The concept of processing concrete to a polished finish is, in itself, innovative.  There are three benefits to green or sustainable building – Indoor Environmental Quality, Overall Reduction of a Building’s Environmental Footprint and Energy Efficiency.  Polished Concrete addresses all three of these benefits.

As I stated at the beginning of this article, properly prepared polished concrete provides a green and sustainable flooring solution unmatched by anything currently available.  The process is proven and we are constantly seeing new and more eco-friendly solutions being delivered to the market.  Clearly processing concrete to a polished finish as a final floor is the new wave in green and sustainable flooring.

About CPm contributor, Jim Cuviello:
Jim Cuviello is president of Cuviello Concrete - Polished |Stained |Crafted www.concrete-medic.com Director of the Concrete Processing and Polishing Technical Institute www.polishingtinstitute.org located in Stevensville, MD.