Reprinted from Western Roofing magazine Nov/Dec 2007.

Starting At the Top

California Architect Goes Green

by Frank Palmer, western regional sales manager, Versico

With the growing popularity of the USGBC LEED® standards, architects nationwide are designing buildings with an emphasis on energy-efficiency and environmental friendliness. However, designing an energy-efficient building and constructing one are two completely different things.

Many LEED designs fail to be implemented at the construction phase due to the costs associated with green building products, lack of environmentally-friendly materials, and a variety of other issues. For architect David Hertz, founder and president, David Hertz Architects, Inc., Santa Monica, Calif., LEED was more than just a consideration for his architectural firm’s new office building, it was the only option.

Not only does Hertz run his own architectural firm, which is heavily vested in green building solutions, but he also founded and owns Syndesis Inc., a company that specializes in the creation of sustainable strategies and environmental products. So, as an architect and an environmental strategist, LEED holds a special importance to Hertz. When he decided to purchase a rundown restaurant and convert it into a new office for himself and his fellow architects, LEED was his guiding light.

“As an architect and a teacher I feel a deep commitment and moral obligation to use less energy than I produce,” said Hertz. “I’m always trying to get my clients to incorporate green concepts into their buildings, so when I decided to remodel this building and make it my company’s new office, I had to practice what I so often preach.”

The result of the extensive remodeling process is the potential for one of the highest rated LEED buildings in the entire United States. Virtually everything that went into this building is green, including non-VOC paint, recycled workstations, recycled denim insulation used in the walls and ceilings, and tons of Syndecrete, a permeable concrete-like substance invented by Hertz himself. Although no LEED rating has been awarded as of yet - it typically takes a year to get an official ranking from the USGBC – Hertz said he anticipates the building to receive Platinum status, the highest ranking available.

Before you even step foot in the office however, the building’s green qualities are apparent on the roof. Because roofs play such an important role in the overall efficiency of a building, Hertz paid special attention to the materials that would don the top of his new office. After considering spray polyurethane foam and acrylic coatings for the rooftop, Hertz opted for polyisocyanurate insulation and two reflective single-ply membranes manufactured by Versico LLC. Combined with photovoltaic panels and a modular roof garden, Versico’s single-ply membranes create an energy-efficient and environmentally-friendly rooftop that will provide a variety of benefits for Hertz and his employees for years to come.

“David was considering an SPF and coating system for the building because he thought it would give him the best R-value,” commented Justin Ewart, president and owner of Allied Waterproofing Systems Inc., the contractor that installed the roof system on Hertz’s office. “However, SPF is not a viable long-term solution for energy-efficient buildings because the foam breaks down over time, reducing its insulating properties. Attaching polyiso insulation under the Versico TPO guarantees the insulation to maintain its R-Value over the life of the roof. After we sat down with David and explained the benefits of Versico’s single-ply membranes and polyiso insulation, he was sold.”

Allied is one of California’s leading installers of energy-efficient and green roof systems. They have received numerous certifications from roof garden manufacturers and they have also contracted with various solar companies to work in conjunction with them as they install solar panels at various projects.

“We are committed to improving the environment through the use of high-quality green roof and solar panel products,” commented Ewart. “For new construction roof garden projects we always specify Versico’s TPO membrane as the waterproofing agent because it is a quality material with proven durability. Long-term, sustainable materials are an important aspect of any environmentally-friendly rooftop, which is why Versico is a perfect fit.”

For this project Allied installed two different Versico membranes on the building’s rooftops, Versi-Weld® TPO and Versi-Flex® PVC, two reflective, heat-weldable products. These TPO and PVC products offer superior reflectivity and excellent heat weldability, features that played integral roles in Hertz’s design. “I wanted the reflectivity for the exposed membranes as a way to reduce my energy demands as well as the urban heat island effect,” said Hertz. “Plus I ended up using heat-weldable photovoltaic panels, so Versico’s PVC membrane was a perfect fit.”

Before Allied could install the unique roof system, the building had to be remodeled. Hertz, who admitted to being very hands-on throughout the entire project, oversaw the remodeling efforts that took two separate, but adjoining buildings, and converted them into one. While most of the interiors were gutted out, Hertz said more than 90% of the exterior shell was either kept in place or reused somewhere else within the construction process.

After the two buildings were combined and the structural integrity was beefed up to carry the additional weight of the future roof garden, Allied began installing the roofing products on the building’s three rooftop levels. For the largest roof level, a flat surface that covers about one-half of the entire building, Allied began the installation by mechanically fastening a layer of 1/4” DensDeck® to the plywood deck. Next, Allied mechanically attached Versico’s 45-mil Versi-Weld TPO membrane using the company’s 2 1/2” HPVX #15 fasteners and 2 3/8” HPV-XL insulation plates. No insulation was required for this portion of the roof because of the aforementioned recycled denim insulation that was installed into the roof cavity from the interior of the building.

It is this rooftop that also features the modular roof garden, which Allied later installed directly on top of the TPO membrane. The trays were pre-planted and delivered directly to the jobsite, making their installation easy and efficient. The easy-to-install roof garden not only adds aesthetic value but it also helps alleviate excessive stormwater runoff and provides additional insulating value for the office below.

“Roof gardens are an excellent way to add aesthetic value and energy efficiency to any building and modular systems such as this one are becoming very popular,” commented Ewart. “For a long time roof gardens were burdensome to install and maintain but the technology has progressed substantially in the past few years and they are a more attractive option for building owners than ever before.”

The highest, as well as the smallest, roof surface on the renovated building is arguably the most important in regards to energy efficiency and the LEED standards. The roof, which sits atop an old bell tower that has been transformed into a clerestory full of windows, is where the energy generating photovoltaic panels were installed. For this portion of the building Allied mechanically attached 1/4” DensDeck to the 1/2” plywood deck and covered that with a layer of Versico’s fully adhered, 50-mil Versi-Flex PVC. After the membrane was installed, Allied heat welded the photovoltaic panels directly to the PVC membrane, creating a monolithic assembly that reduces the likelihood for leaks.

In addition to the photovoltaic panels on this roof section, the clerestory itself serves a purpose by allowing natural sunlight to pour into the building. The plethora of light reduces the building’s needs for energy-guzzling light fixtures and adds aesthetic appeal that enhances employee morale.

“One reason we advised David to install Versico products on his building was because of Versico’s flexibility when it comes to roof gardens and photovoltaic panels,” said Ewart. “Most manufacturers are reluctant to put their name behind these kinds of products and systems, but Versico had no problem incorporating them into its existing warranties. This project received a ten-year, total system warranty directly from Versico,” he added.

Below the clerestory is an arched, or barreled, roof surface that features old timber framing viewable from inside the building. Allied began by installing a two-inch layer of Versico’s MP-H polyiso insulation. The insulation and its accompanying R-value was essential for keeping the timber framing open on the interior, something Hertz felt strongly about. Not only did Hertz want the excellent R-value that Versico’s polyiso provides, but California’s stringent building code, Title 24, demanded an R-value of no less than 11. Versico’s 2” polyiso board features an R-Value of 12.10.

Allied fully adhered the polyiso to the building’s plywood deck with Versico’s VersiGrip® adhesive and then topped it with a fully adhered layer of 1/4” DensDeck. After the DensDeck was installed, Allied fully-adhered Versico’s 45-mil, white TPO membrane using the company’s low-VOC TPO bonding adhesive. Next, 60 aluminum stand-offs were installed and flashed in with Versico’s TPO flashing membrane. The stand-offs allowed additional solar panels to be installed on this portion of the roof as well.

The reflective membrane, in addition to the polyiso insulation, helps keep the sun’s solar UV rays from entering the building and driving up Hertz’s air conditioning costs, just one way in which Versico’s roofing products helped this building in its pursuit of LEED certification. The membrane also helps increase the efficiency of the building’s solar panels by keeping the rooftop cool. Although this does not directly result in any LEED points, it will help lower Hertz’s future energy bills. All told, the roofing products Hertz selected for his new office will definitely have a significant impact on the final LEED rating.

“The roof was an integral part of our LEED-based design,” commented Hertz. “We got a cool roof point, a stormwater retention point, and a photovoltaic point as well. Whatever our final LEED rating ends up being, one thing is for certain, the roof played a very important role in obtaining it.” •••