Willis A. Smith Construction Inc., a Florida building contractor and construction manager, had operated from a converted warehouse complex for 36 years when continued growth absorbed five earlier expansions and dictated a need for still more office space. In response to increasing interest in green construction programs, the contractor applied leading-edge design, technologies, materials and construction practices to create a new 18,000-square-foot (1,672-m2) headquarters facility, completed in January. The building has earned LEED Gold certification from the U.S. Green Building Council, Washington, D.C.
David Sessions, company president, championed the LEED-certified building program because his organization frequently works as a construction manager as opposed to traditional hard-bid contracting. This role demands the construction manager to maintain an owner’s perspective in design, budget development and overall project management.
“We had served as construction managers for several ‘green’ building programs in recent years, so it was logical for us to build a state-of-the-art green facility,” Sessions said. “LEED certification is the construction industry’s most universally accepted and demanding criteria. We viewed this as an opportunity for us to learn firsthand from our own experience and to study some common misconceptions about LEED, such as adding costs to a facility’s construction programs. We wanted the building to create a strong community statement about our capabilities but relatively simple and unassuming, so that our customers would become interested in sustainability, green design and construction practices.”
Team Effort
Willis A. Smith Construction ranks among the most prominent construction management firms in southwest Florida. The company has 14 LEED-accredited professionals on staff, and more are planning to earn the enviable credential. The company also holds corporate memberships in both the USGBC and the Florida Green Building Coalition. By designing and building its own project to LEED standards, Willis A. Smith Construction had the latitude to involve the entire staff in identifying both proven and innovative concepts. Furthermore, the collaborative program could be judged objectively in terms of the incremental cost of alternatives for the roof, insulation values, HVAC, lighting and material content. Every feature was scrutinized for contributions to LEED and the life cycle benefits.
“We now openly share the lessons we learned and some unique aspects we now would do differently,” Sessions said.
Capturing Creativity
Rather than working under the constraints of a budget-driven project, the force behind the new headquarters was to achieve enough credits for the rigorous LEED Gold designation. The commitment to a green building program also played to the context of the new building’s 2.6-acre (1.05-hectare) site within a large, mixed-use commercial development of energy-efficient residential, corporate business parks, recreation, medical, retail and school segments. When fully built out, the development will represent one of the larger green communities in Florida.
“We had no preconceived notions and started with just a blank piece of paper,” Sessions said. “Input was invited from every level of the company for assessment. Our administrative staff made recommendations about their desired functionality and flow, while project managers were directed to thoroughly acquaint themselves first with the LEED Reference Guide before advocating their ideas.”
The collective charette focused on six areas of green construction that included interior and exterior environments; materials; energy and water efficiency; and innovative elements. The Lawson Group Architects, a local firm, translated the adopted features into formal documents and specifications. The result was a contemporary building reflecting a popular architectural style in southwest Florida. It is situated within a liberally landscaped site whose traits also contributed to the LEED score.
New Method
Because the owner has been an authorized Butler Builder, Sessions combined the advantages of the Kansas City, Mo.-based Butler Manufacturing pre-engineered structural framing and heavily insulated VSR architectural standing-seam metal roof system with an advanced method of concrete wall construction that applied an insulated concrete form system.
The cast-in-place concrete wall construction has a synthetic stucco exterior finish above a manmade stone wainscot. The recycled steel
(48 percent post-consumer and 26 percent preconsumer recycled content) that Butler uses to fabricate metal building systems helps meet LEED 4.1. The steel systems earn credits by inherently reducing the nation’s solid waste stream. The concrete walls and drywall used for the interior finish also have recycled content; in this instance, the fly ash salvaged from the exhaust scrubbers of power plants instead of virgin-mined gypsum.
The full-height insulated concrete walls created with the ICF system also delivered exceptionally strong construction rated to withstand a calculated 200-mph hurricane. The walls cost a 10 to 15 percent premium over traditional masonry construction, but the contractor concluded that the amount of reinforcing steel needed for the project could be significantly reduced overall while achieving cost savings on future projects using the same hybrid materials combination. Equally important, the roof assembly and preinsulated concrete walls collectively deliver an energy-efficient, R-30 building envelope.
Durability and energy efficiency are also ingrained in the Butler standing-seam metal roof system. This roof system originated 40 years ago and has since revolutionized the use of impermeable steel as a roofing material. The system has earned UL Class 90, Miami-Dade County and other roof certifications equating to withstanding theoretical 130-mph wind forces. The recycled steel in the metal roof and reduced “heat island” effect from the reflective roof coating contributed further LEED credits.
Other Efficiencies
Completing the building envelope are low- E (51 percent light transmission) insulating, impact-resistant windows fitted with shades on the sides with direct sun exposure. A clerestory over the core cubicles of the open-plan work area enhances the muted natural light admitted by the glazing. Ironically, the project was ineligible for LEED credits for daylight harvesting because the interior falls just short of the required foot-candles of daylight. This could be corrected on future projects simply by using larger windows, one of several lessons learned from the project.
Even so, enough natural daylighting reaches the interior space that only 50 percent of the T5 fluorescents operate on sunny days and are supplemented by task lighting provided at work stations.
The building’s air conditioning is a split system with eight zones. The units range from a 15 to 18 Seasonal Energy Efficiency Ratio rating that well exceeds the code minimum. Automatic thermostats and humidity control ordinarily set back the facility’s HVAC system after hours. The zones can be selectively overridden to avoid cooling the entire facility whenever someone is working late.
Although purposely omitted from the original design and construction, the building now has a photovoltaic energy system to reduce energy consumption even more. The solar system eliminates 24,000 pounds (10,800 kg) of carbon dioxide annually. Any surplus generation flows back to the grid for a credit charge, underscoring why such buyback elements in rate structures and state and national rebates now make the payback on solar technology very economical.
The system array consists of approximately 60 American-made solar panels. Each panel, which employs low-cost, silicone wafer technology, is capable of producing 205 watts of DC power. The energy passes through a power converter for conversion to usable AC current. Sessions emphasized that the collector panels were installed on top of the building without penetrating the standing-seam metal roof. Instead, the panels are held in place by nonpenetrating clamps along the ribs of the standing seams.
Healthier Building
The interior utilized low- or zero-emitting Green Seal products exclusively to sustain quality indoor air (Green Seal is based in Washington, D.C., and provides science-based environmental certification standards). The paint was a proprietary line with zero-VOCs, and the wood trims, cabinetry, carpet and adhesives are free of formaldehyde. Once again, interior finish products also have recycled content.
Fresh and Clean
The building’s water efficiency-a 72.5 percent reduction in total potable water savings qualified for LEED credits. Sessions is notably proud of this feature because it earned a LEED innovation credit. The water conservation provisions respond to the drought conditions that have held southwest Florida in a stranglehold in recent years. Rainfall runoff from the roof, along with condensate from the AC units, are captured and flow to a dual-cistern system. From there, it is treated, filtered and pumped through the building for toilet and urinal flushing.
The plumbing system utilizes dual-flush toilets as well as low-flow faucets and urinals to achieve a 30 percent reduction in potable water use. A modest 1-inch (25-mm) of rainfall collected from just half of the building’s roof area is enough to recharge the two-month reserve stored in the cistern system. The runoff flows into the first of two precast concrete cisterns with a total capacity of 6,000 gallons (22,712 L). The contractor calculated the capacity as enough to bridge the area’s relatively dry mid- March through mid-May period. Any excess flows to a pond.
The Great Outdoors
More than 50 percent of the irrigation water reduction derives from the landscaping plan and irrigation system. The flourishing plantings might suggest otherwise but are exceptionally water-efficient and indigenous to the region. These were selected for inherent drought resistance and proven applications to xeroscaping. To augment the benefits of the roof’s cool roof coating on the heat island effect, the grounds received 22 strategically spaced, 25-foot- (8-m-) high oak trees. Their calculated growth within the next five years will shade half of the area.
Passing Along Savings
Sessions said the somewhat experimental building program cost 6.87 percent more than conventional construction, but achieving the enviable LEED Gold rating would cost only 3.5 percent for future clients. The company can now draw from firsthand experience to recommend important innovations and responses to environmental, constructability and life cycle performance considerations to help future clients benefit when pursuing similar green building programs.
Elise Lipoff is the public relations specialist for Willis A. Smith Construction Inc., Sarasota, Fla. As a publicist and communications whiz, Lipoff capitalizes on the trends of social media, furthering the reach and impact Willis A. Smith Construction has on a local and national level. Visit
www.willissmith.com.
