in the news

Back to Guest Features

july 2013
guest feature article

New Corporate Green Roof is First on a Commercial Building in Historic Durham, N.C. Downtown District

David Aquilina


By David Aquilina
Strategic Storyteller


All Photos Courtesy of Xero Flor America Unless Otherwise Noted


 The new Xero Flor America HQ in Durham, NC; Photo Courtesy of Sam Roberts.

Original 1854 tobacco boom town, home of the Durham Bulls, and penned the "Foodiest Small Town in America" by Bon Appetit Magazine, Durham is also North Carolina’s first commercial district on the National Register of Historic Places.

Durham's Downtown Historic District is a compact, unified, relatively little disturbed commercial area with buildings dating principally from the first four decades of the twentieth century, vividly expressive of the city's boom period.  Where the original Durham Station and tobacco fields once stood, the downtown area itself survives as a closely knit and tightly organized collection of outstanding early twentieth century commercial, public, and ecclesiastical buildings and appropriate background structures
of that period.

 Postcard during Durham's Historic Disctrict's Heydey; Photo:

Currently, the area is entering a renaissance, as developers explore new possibilities with its architectural heritage.  Factory and warehouse buildings from the area’s old tobacco companies are now filled with lively bars and restaurants, shops, and high-tech offices.  Early 20th century storefronts are now full of exciting loft apartments and condos, attracting life back to downtown and its unique charm.

Some of Durham's newest highlights are the expanded Bulls ballpark, American Tobacco complex, and the Durham Performing Arts Center; Photo:

Xero Flor America (XFA) is now headquartered here in downtown Durham, North Carolina.  XFA is the official and exclusive distributor for the Xero Flor Green Roof System in the U.S.  The system utilizes pre-vegetated mat technology engineered in Germany and refined over 40 years of continued research and development.  Xero Flor mats, planted with varieties of Sedum, have been rolled out on tens of thousands of rooftops worldwide covering hundreds of millions of square feet.

 Beautiful view of the Xero Flor America HQ; Photo Courtesy of XFA.

In the U.S., Xero Flor America has installed its system in 38 states.  The Xero Flor green roof on the Dearborn Truck Plant at the Ford River Rouge Complex in Michigan measures 454,000 square feet.  It is the largest green roof on a single, freestanding building in North America and one of the largest in the world.  The new Javits Convention Center green roof in New York City also uses Xero Flor.  When completed, it will total 292,000 square feet and will be second in size to the Ford installation.  Other Xero Flor America (XFA) projects include seven green roofs at Columbia University and the five-roof installation on the Silver City Townhomes, an affordable housing project in Milwaukee, Wisconsin.

 The Xero Flor America HQ in bloom; Photo: Sam Roberts.

In July 2012, XFA moved into renovated offices in The Republik Building at 211 Rigsbee Avenue in downtown Durham’s historic district.  The new 2,343 square-foot Xero Flor green roof atop the building, completed in February 2013, is the first green roof installed on a historic building within the boundaries of the district.

 Photo: XFA.

“The green roof at 211 Rigsbee may not have the impressive scale of some of our other projects,” said Clayton Rugh, Ph.D., general manager and technical director, Xero Flor America (XFA).  “But is has the potential to be a landmark in the greening of downtown Durham, especially to show how green roofs can help solve the region’s stormwater problem.”

 Photo: Sam Roberts.

Moving Downtown

XFA had its offices adjacent to its Southeast regional production fields and facility outside Durham.  Last year, the company decided to get more connected to the business community downtown.  “We started searching for offices in the historic district — ideally, in a building where we would have the opportunity to showcase our green roof system,” said Rugh.

  Photo: XFA.

Robert Shaw West, chairman and CEO of The Republik, a local firm offering brand strategy and communication services, had the solution.  His offices are located at 211 Rigsbee. Originally constructed in the 1940s for the Durham Insurance Service Company, the building is known to local history buffs as the home of WSSB radio.  West purchased the property from the City of Durham.  The Republik renovated the outmoded offices into a more contemporary, open and collaborative work environment.  They had space available on the second floor for XFA to lease.

 211 Rigsbee Avenue; Photo: Sam Roberts.

“It was serendipity.  Clayton was looking for offices downtown, and we had space,” said West.  “Plus, we had to re-roof our building last year.  Since we needed a new roof, it was an ideal time to also consider adding a green roof, which supports our commitment to sustainability.”

Going Green Up on the Roof

XFA moved into 211 Rigsbee in July 2012.  The 2,343 square-foot green roof was installed in February 2013.  In addition to the standard building permit process, putting a green roof on the historic building required additional review and approval.

 Photo: Sam Roberts.

“Except for certain minor items, such as re-painting a previously painted surface, most changes to building exteriors within an official local historic district require a Certificate of Appropriateness (COA),” explained Anne Kramer, urban designer with the Durham City-County Planning Department.  The goal is to ensure preservation of the historic character of the buildings. Alterations to roof coverings or forms require a COA.

 Photo: Sam Roberts.

With the COA from the Durham Historic Preservation Commission, XFA and The Republik had the green light for the green roof.  The project demonstrates that properly planned and installed green roofs can be compatible with historic preservation.

Photos L-R Courtesy of: XFA; Sam Roberts.

The XF301+2 system option was selected for the project.  Fully saturated, it weighs only 10-11 pounds per square foot, making it ideal for the retrofit.  Xero Flor America showcases three of its plant palettes on the roof: Appalachian Plant Mix, Southern Plant Mix, and the Mid-Atlantic Plant Mix.

Accessible by an external roof ladder, the green roof is not open to the public.  XFA does take potential clients and other visitors up on the roof to show them the Xero Flor system and explain how it works.

 Photo: Sam Roberts.

“As a forward-thinking company known for innovation, The Republik wanted to lead the way with the first green roof on a historic building within the downtown district,” said West. “Other business owners and developers in Durham can now see how practical and beneficial a green roof can be.”

Stormwater Management in Durham

“Our region gets 45-50 inches of rain annually.  That is more than Seattle,” said Chris Dreps, executive director, Ellerbe Creek Watershed Association, Durham, N.C.  “Rainwater running off impervious surfaces like roofs, parking lots and roads picks up pollutants that harm our waterways.”

 Ellerbe Creek; Photo: City of Durham

The city center of Durham sits on the watershed boundary between the Jordan Lake and Falls Lake Reservoirs, major sources of drinking water for the Triangle region of North Carolina.   Pollution carried by stormwater has impaired both.  Both are subject to North Carolina state rules for reducing pollutants and nutrients in the Neuse River basin and the Pamlico Sound.   Runoff from The Republik Building goes into Ellerbe Creek, which has the highest population density of Durham’s urbanized watersheds, and flows on to Falls Lake.

Photo: Sam Roberts.

“Given its size and the specific Xero Flor option installed, the green roof atop the building on Rigsbee can prevent more than 50,000 gallons of stormwater runoff annually,” said Rugh.

Could the green roof at 211 Rigsbee signal the future of stormwater management for Durham’s downtown?  Peter Raabe, North Carolina conversation director for American Rivers, the nation's leading river conservation organization, hopes so.

 Photo: Sam Roberts.

“Our office in Durham is on the fifth floor of the Snow Building on Main Street.  Looking out my window during storms, I see the rain pounding down on the roofs of downtown buildings and surging into the streets.  That runoff then rushes through the city’s stormwater drains that flow right into the creeks that feed the Falls and Jordan Reservoirs,” said Raabe.  “That inspired a vision.  What if some of those were green roofs?”

 Photo: XFA.

According to an analysis conducted by American Rivers, there are 777 buildings in Durham’s downtown district with a total of nearly 5.2 million square feet of rooftops.  Annual runoff from those roofs tops 140 million gallons.

Photos L-R Courtesy of: Sam Roberts; XFA.

Based on the area’s annual precipitation, and a realistic annual retention efficiency rate of 75 percent, every square foot of the type of green roof atop The Republik Building can prevent about 20-23 gallons of stormwater runoff annually.  Thus, if 25 percent of the roof surfaces downtown were covered by similar green roof assemblies, runoff in downtown Durham could be reduced by an estimated 27-29 million gallons annually (roughly 20 percent).

The Republik Building / Xero Flor America HQ; Photo: Sam Roberts.

“I am convinced more green roofs will be going up in downtown Durham,” said West.  “They are important for reducing runoff and protecting the environment.  Other building owners will also see the benefits of green roofs for improving energy efficiency and enhancing downtown offices, apartments and condos with views of green space.”

David Aquilina

Publisher's Note:  See the Xero Flor America Headquarters Green Roof in The Greenroof & Greenwall Projects Database. is featuring it as our Project of the Week for July 22-28, 2013.

David Aquilina, Strategic Storyteller

David Aquilina

David Aquilina, Strategic Storyteller (, is a corporate communications consultant and freelance writer.  Xero Flor America is one of his clients.  David makes his home up on the edge of the northern prairie in Minneapolis, Minnesota.

Contact David Aquilina:

The opinions expressed by our Guest Feature writers and editors may not necessarily reflect the beliefs of, and are offered to our readers to simply present individual views and experiences and open a dialogue of further discussion, debate and research.  Enjoy, and if you have a particular comment, please contact the author or send us an email to:


Back to Top



Ad: American Hydrotech