Green construction gains momentum
by RaeAnne Marsh

Plastic‑lined chain‑link fencing has become a presence around town as construction projects address the dust‑control issues of our hot, dry Valley climate. But the pink parking lot of Butte Papago Church of the Brethren, in Scottsdale, hints at the existence of an alternate method.

Continuing at a steady pace, commercial construction is not in the same highly‑publicized slump of the residential market. But the commercial construction projects have issues of their own, and dust control is one of the bigger ones. Water helps minimize dust, but there’s run‑off that must be dealt with. Other dust‑control solutions have consisted of coatings, which are water‑soluble and wash away in the rain, and polymers, which are not resistant to ultraviolet rays and break down in the desert scorch.

With growing ecological awareness and increased interest in LEED points (Leadership in Energy and Environmental Design Green Building Rating System), products and techniques are being added to builders’ menu of options.

The Butte Papago Church parking lot is made of an aggregate mixed with T.O.P., a special emulsion developed by Environmental Stabilization Solutions (nicknamed “enssolutions,”entac‑emulsions.

com), part of a Canadian company but whose offices and manufacturing plant are in Glendale, Ariz.

One hundred percent organic, the emulsion is made from pine pitch sheered into small particles.

“The smaller the particles, the better the emulsion,” explained Enssolutions’ general manager Patrick Ford. “We’ve developed a technology that allows us to sheer the pitch extremely fine.” The emulsion can then be mixed with decomposed granite aggregate– which is available now in 10 different colors, the church’s pink being one of them. “They wanted the parking lot to match their building of pink granite.”

With the parking lot, longevity is a desired attribute. On construction sites, short‑term use is what is needed. The LEED‑friendly product works for both, and serves the construction site in multiple ways.

Following the rough grade step at commencement of construction, the emulsion can be applied as a simple topical spray to seal the entire area, enabling the builder to avoid the migrating dust that accompanies disturbance of the land surface. It can also be mixed with an aggregate–which may be asphalt, if that is preferred–and laid down on the apron where all the construction vehicles enter and leave. “It’s biodegradable,” emphasized Ford. “When the project is done, they can break it up with a tractor and pave right over it.”

A few months, then, for the construction site use. How long, however, will the parking lot last? According to Ford, it will last as long as it is maintained, said maintenance consisting of a twice‑yearly “fog seal” to reapply the emulsion. “For an 18,000‑square‑foot parking lot, that will take about 20 minutes and probably cost about $150.” And the lot can be used again right away. Also, Ford noted, it can be applied at night.

Comparing the longevity of aggregate mixed with this emulsion to the longevity of asphalt, Ford explained that asphalt lasts in Arizona 10 to 15 years due to the harsh weather conditions. Plus, its dark color contributes to a heat sink effect that raises the temperature. Decomposed granite aggregate is available in lighter colors.

Referring again to the church, Ford said, “You can walk on this parking lot in your bare feet in the middle of the day.” He has found, however, that some people have an asphalt mind‑set, and relates the company will also mix the emulsion with an asphalt aggregate.

The company, whose staff is comprised of environmental engineers, geologists, and professionals that have been in the stabilizing business for more than a decade, also offers solutions for broader use than construction and commercial projects. Other environmentally friendly uses Ford cited include walking trails in Rio Salado. “It stabilizes [the ground]; if it’s raining, you won’t lose your footing because it won’t be muddy.” It can be applied by hand, truck, or helicopter.

Only recently gaining mainstream acceptance, “LEED is more and more required, especially by some cities for government buildings,” said Christa Langer, a LEED Certified Professional with Scottsdale‑based PK Associates (paulhoehler.com). 

In February 2005, Governor Napolitano signed and executive order implementing the LEED green building standard for all new state‑funded buildings. The City of Scottsdale followed one month later with adoption of a resolution approving LEED building policy for new city construction.