As green building practices establish themselves as the de- facto construction standards, each individual component of a new building project falls under scrutiny with regard to its contribution to meeting the new “Green” requirements. Indeed, entire projects are now viewed as not just the sum of their parts, but rather as an integrated system where each piece must contribute to a greater overall efficiency. A case in point is the new choices for flooring. This article looks at how flooring can support and enhance a green building project. In concert with eco-responsible building and design trends, we believe “less is more” and with the advances that have been made in the polishing and finishing of natural concrete floors, many building teams are choosing to forego the traditional flooring options, requiring less flooring material, for a more beneficial use of native materials (polished concrete).

Green approval is becoming synonymous with Leadership in Energy and Environmental Design, (LEED) certification. LEED addresses the major concerns of green building including: the use of resource-friendly materials, energy saving design, and providing healthy indoor environmental quality (IEQ). Amazingly, the natural attributes of a finished or polished concrete floor assist in all those areas. This can add up to significant LEED point earnings, as shown in the chart at the end of the article. Let’s consider these areas in more detail.

Resource Friendly – (a.k.a. reduce/re-use/recycle)

 

This one is pretty obvious. Utilizing concrete as your finished floor eliminates the need for floor covering products, (i.e. tile, stone, VCT, carpet, wood, etc.). In our opinion, putting a floor over a floor is a bit redundant and this is one of those construction areas where going green actually eases the building budget. Of course, you can apply those savings toward other green credit areas, such as landscaping or supplemental electrical sources. We now understand that traditional floor coverings, besides costing money, leave a huge carbon footprint, (the sum total environmental effect of a product’s life cycle). Carbon footprint assessments include valuations for: material extraction, manufacturing, transportation, installation, maintenance, disposal and replacement and these costs are paid for initially by your budget, but ultimately by our planet’s air, soil and water quality.

The carbon footprint of concrete is low because concrete consists of portland cement, stones, and water. These natural ingredients are almost always extracted locally, which results in a reduction in transportation costs and carbon emissions. As recycling efforts become mainstream, sometimes concrete ingredients are not extracted at all.
Another recycling strategy is in the use of fly ash, a bi-product of coal-burning energy plants. Fly ash is added to the mix, displacing some of the portland cement and resulting in a stronger cure. Using up otherwise useless fly ash also reduces the need for landfills, which of course nobody wants for a neighbor.

Remember: Traditional floor coverings, besides costing money, leave a huge carbon footprint.

Reuse

As we mentioned, carbon footprint also involves maintenance and replacement. We will talk about the ease of maintenance a little further in the article. But for now, let me ask you this, “When was the last time you had to replace a concrete slab?” For most people that answer would be  “never” as typically a slab will outlive the building itself. Which brings us to the LEED credit of “Building Reuse”. In a renovation or addition project, the reuse of the concrete slab can be the largest contributing factor towards achieving credit points.

Energy Savings

Finished concrete saves energy in several ways. In the summer time, a slab in contact with the ground draws the earth’s own natural cooling abilities into the building. In the winter, if a building has been designed to expose the slab to natural sunlight, it will soak up this radiant heat. Then at night the slab will release the heat into the building to provide a more uniformly warmer interior. Both of these are examples of concrete’s inherent thermal mass capability, which save money on heating and cooling costs.

Another aspect of concrete’s energy savings is through lighting. Using reflective (light colored or shiny) concrete allows sunlight to reflect more deeply into the occupied spaces. The polished concrete provides a brighter, more naturally lighted space that reduces the need for electrical lighting and lowers energy costs. It is universally agreed that natural light is almost always preferable to artificial light in the workplace. Studies have shown that natural daylight increases comfort, productivity, and even retail sales. Used outdoors, reflective concrete helps reduce the “heat island effect” by reflecting heat away from the property and keeping the building cooler. There is also a surge in the residential use of finished concrete, especially since natural daylight provides a warming effect.

Reduced Maintenance

The final savings aspect of finished concrete is in reduced maintenance. Would you rather strip and wax VCT, scrub and seal tile and grout, steam clean carpets, or use a microfiber dust mop to scrub your concrete floor? Easy answer and so is the concrete floor maintenance process, especially when we use new lithium-silicate based cleaners that actually help extend the life cycle of a polished or natural concrete floor. Easier maintenance on a floor that will last many times longer then a floor covering sounds great to us.

Healthier Environmental Quality

Indoors is where about 90% of our time is spent. And without a healthy indoor environment, health issues are the documented result. According to the U.S. Green Building Counsel, it is estimated that 17 million Americans suffer from asthma, and 40 million have allergies. This contributes to millions of days absent from work and school. Indoor environmental quality (IEQ) covers airborne contaminants as well as Volatile Organic Compounds (VOCs) chemical fumes, lighting quality, temperature, air speed, and humidity. Here’s the breakdown: particulates, airborne fungal spores, fine dust allergens from dust mites, cats, dogs, and insects and other pets (77%); Gases: CO, CO2, radon, VOCs, tobacco smoking, and other combustion sources (21%); Other: uncomfortable temperature, humidity, lighting, etc. (19%). The totals are more than 100% due to the fact that one building can have several, but not necessarily all, of these problems.

The type of flooring used will have a major impact on all these IEQ factors. However, consider how a natural polished or stained concrete floor helps to resolve many of them. A concrete floor will not require the use of VOC adhesives or sealers, in contrast with carpet, wood, stone, tile, and especially VCT. The densifier chemical that hardens and assists in the staining and polish procedures does not create any off-gassing. The lithium silicate creates a hardening reaction with the calcium hydroxide occurring naturally in concrete.

Concrete floors require reduced maintenance procedures. Meaning reduced chemical use, as compared to the stripping and waxing used to maintain VCT and other surfaces. According to the EPA, 40% of cleaning chemicals can contribute to chemically related work injuries. So any effort to reduce the need for those chemicals is a step in the green direction.

Floor coverings, especially carpet, will harbor dust and mold allergens. Trapped moisture is also a problem, both from spills and cleaning procedures. Carpets are a sink for urine, odors, spills, and other pollutants. In contrast, a densified, polished and stained concrete floor has reduced porosity, greatly decreasing the penetration of moisture and hence, the growth of bacteria. The floor should be polished to a maximum grit level for best results. Additional non-toxic options for grinding, hardening, and protecting concrete are also available.

As far as concrete maintenance goes, lithium based cleaners will continually react with the new calcium hydroxide generated by the concrete due to foot traffic, etc. Microfiber dust-mopping with no chemical additives are all that’s necessary on a routine basis to combat abrasion, and maintain a uniform luster on the surface. Simpler cleaning procedures translate to a healthier building, and healthier occupants.
In our opinion, an additional IEQ issue is safety. According to Nu-Safe Floors, the average cost of a slip-and-fall is 18,500 dollars, which translates collectively into billions of dollars per year just in the US. Slip-and–fall is the second leading cause of accidental death and injury, next to automobiles. It accounts for 57% percent of general liability claims, and 51% of worker’s comp claims. Furthermore, 50% of slip-and-fall accidents are blamed on flooring. How do we combat this? Well, it is important for building owners to know how safe their floors are. Slip tests measure the coefficient-of-friction of a floor. A slip-test device called a tribometer physically senses a floor’s slip resistance. More and more insurance companies are requiring this test. How does finished concrete measure up? Very well! Since concrete is not being waxed, slip and fall issues are reduced. Static and dynamic co-efficient of friction slip-tests have shown finished concrete to exceed both OSHA and ADA testing standards. Good news! This reduces potential liability claims for both owners and tenants.

Fact: Slip-and–fall is the second leading cause of accidental death and injury, next to automobiles

Green Issues Are Important!

Green building legislation has been increasing in recent years, meaning that new and renovated buildings will be legally required to address the green issue. LEED addresses all of the concerns that have been identified previously, using a comprehensive point system to qualify for one of four certification tiers: Certified, Silver, Gold, and Platinum, each equaling points on the LEED scale. A “Certified” LEED project equates to 26-32 points, “Silver” is 33-38 points, “Gold” is 31-51 points, and “Platinum” is 52-69 points. A casino in Las Vegas is going for a platinum LEED certification, which means if they qualify, they will get a 50% property tax break granted by the state of Nevada, which will quickly repay all extra expenses related to going green. Add to that the ongoing water/energy savings, increased productivity and property value, and it’s obvious that going green is profitable for the bottom line. Obviously, finished concrete flooring can be a major factor in achieving these goals. In conclusion, the following is a reference guide that shows the different LEED credits that concrete flooring helps to achieve.

Concrete in LEED Credit Guide

Leed Credit	Title	Strategy	Possible Points
SSc7.1	Heat Island Effect	Use reflective concrete for a high solar	2
		reflectance index. This keeps the area
		surrounding the building cooler.
EAc1	Optimize Energy performance	Utilize thermal mass of concrete in	11
		building performance calculations to
		achieve energy cost savings of up to 45.5%
MRc1	Building Reuse	Reuse existing concrete for major	2
		renovation or addition to help achieve 95%
		building material reuse
MRc2	Constr. Waste management	Divert waste concrete from demolition	3
	Divert 95% From Disposal	to recycler
MRc4	Recycled Content	Use recycled concrete or fly ash to help	3
		achieve a building total of 30% recycled
		content
MRc5	Regional Materials	Use concrete manufactured within 500	3
		miles to help achieve a total of 40%
		regional materials
EQc4.1	Low-Emitting Materials	Use exposed concrete to eliminate the use	1
		of harmful adhesives and sealants
EQc4.2	Low-Emitting Materials	Use low VOC stains and sealers on	1
		exposed concrete
EQc7	Thermal Comfort Design	Utilize thermal mass of concrete to assist	1
		in achieving the thermal comfort standard
EQc8.1	Daylight 95% of Space	Use reflective concrete inside to increase	2
		daylight footcandles
		Total LEED points affected by concrete	29

References:

USGBC New Construction Reference Guide version 2.2
EPA
OSHA
ADA
Protecting The Built Environment – Cleaning For Health by Michael A. Berry PHD

About the Authors
Adam A. Schoonover is a LEED AP and GreenPoint Rater with over 25 years in design/build construction. He is currently developing GreenRatingCenter.com, a consumer’s guide to green building products.



John J. Dykstra is a flooring/chemical/concrete industry veteran with more than 30 years experience. Published in numerous maintenance/health-care publications and author of the book “Infection Control for Lodging and Hospitality Establishments” published by John Wiley and Sons, Dykstra currently conducts coefficient-of-friction floor validations.