Denver Place: An Energy-Efficient City Within a City

April 4, 2006

As Colorado’s third-largest commercial office property, Denver Place (located in the heart of Denver) truly stands above the rest. With two office towers linked by two terraced buildings spanning an entire city block, Denver Place is a showcase and a prominent part of Denver’s cityscape.

Built in the early 1980s, Denver Place is home to offices, a retail mall, an athletic club, and a hotel conference center, and has been labeled “a city within a city” by Denver residents. Its towers, shaped like elongated hexagons, make them among the most identifiable in Denver’s skyline.

In addition to its unique design, the property has also been recognized by the Environmental Protection Agency (EPA) for being an ENERGY STAR® building. Awarded based on energy consumption and performance of the building, Denver Place helped lead the way in promoting the trend of environmentally friendly buildings.

Located in a region known for harsh weather elements, the 20-plus-year-old roofs on the north terrace and south tower of Denver Place started to fail. As the time neared to re-roof the encapsulated city, the property management company (Amerimar Realty Management Co.) recognized the importance of utilizing materials that contribute to an environmentally friendly property.

“Energy efficiency was an important factor when deciding on a roofing system,” states Lori Carter, property manager of Denver Place for Amerimar. “We wanted a light-colored roof that is durable and reflective.”

Amerimar, a national real estate investment and management firm, stresses initiative and imagination with relation to its buildings. When it was time to choose the roofing contractor to update the Denver landmark, WeatherSure Systems Inc. of Englewood, CO, seemed to be a natural fit.

“We have a history with Craig Garey and WeatherSure Systems Inc., and we know that we can count on their quality workmanship, service, and reliability,” commented Matt Gallo, chief engineer at Denver Place. “Craig recommended using a Versico Inc. Ballasted Roofing System because of the ease of installation and cost-effectiveness.”

In an effort to reduce waste and maintain cost-effectiveness, Amerimar wanted to utilize the existing ballast in addition to pavers; accomplishing this task was a challenge. “With access to the roof only available by elevator, transporting the materials took time,” states Craig Garey, principal of WeatherSure Systems Inc.

The project consisted of two phases. The first phase focused on the 8,000-square-foot terraced area. Covering areas occupied by retail establishments, it was vital to the buildings’ tenants that minimal disruption occurred. The arduous task of removing the ballast, the existing membrane, cleaning the ballast, and transporting the materials via elevator and three flights of steps was done with minimal effect on the building occupants.

Once the existing system was removed, Versico’s 60-mil VersiGard® EPDM membrane was installed. Because it does not require labor-intensive screws to attach the membrane, the VersiGard Ballast Roofing System is an economic alternative to other systems. It also does not require costly adhesives as the membrane is held in place by the ballast and pavers.

Known for its excellent value, dual-seam protection, and low odor, 60-mil VersiGard membrane addressed the need for extra protection while minimizing disruption to the tenants. A typical ballast installation utilizes 45-mil membrane, but Amerimar wanted the added durability. “We chose to use Versico’s 60-mil VersiGard membrane because of its added durability to protect the building from the elements,” says Garey.

Following the VersiGard membrane, the cleaned ballast rock and 900 decorative pavers were installed. The walkway pavers were placed around the perimeter of the building, the rooftop equipment and then positioned in the shape of the Denver Place logo on each side of the roof.

“The complex paver design was a challenge, but the end result really maximizes the value for Amerimar while increasing durability and enhancing the appearance of the roof for tower occupants to see,” comments Garey.

The second phase of the project focused on the south tower. The 12,000-square-foot job presented another challenging installation. Again, the only access to the roof of the 34-story building was by elevator. “The fortunate thing about the entire project is that by using the VersiGard Ballast Roofing System, we were able to keep the number of our crew down to seven,” continues Garey. “When working in tight quarters like this in an urban environment, that makes a difference.”

Amerimar’s commitment to having an energy-efficient building was met by utilizing Versico’s ballast system. Recent studies underwritten by the Single Ply Roofing Industry (SPRI), a recognized technical and statistical authority on the single-ply roofing industry, have been conducted by the Oak Ridge National Laboratory (ORNL) to identify the thermal performance of ballasted roof assemblies.

ORNL’s Andre Desjarlais, a SPRI member, explains that ballasted systems capture and hold onto heat, storing it in the mass of rock on the roof’s surface and thereby preventing its transmission into a building at times of peak energy consumption during the day. Eventually, the stored heat radiates off the roof. “It's just a different mechanism for reducing heat flow into a building,” Desjarlais explains.

Further testing is being conducted to determine if ballasted roofing systems meet ENERGY STAR requirements, but preliminary results suggest that if the ballast meets minimum weight requirements, the system performs as well as light-colored membrane.

“We are delighted with the results of both the north terrace area and south tower,” Carter says. “The light-colored ballast, the paver design, and the strength of the entire system have met our expectations.” Gallo agrees: “WeatherSure provided an economic and durable roofing solution with Versico’s VersiGard Ballasted Roofing System.”

As an integral and easily recognizable part of Denver’s skyline, Denver Place is sure to continue protecting its “city within a city” for years to come while continuing to be an energy-efficient building.

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