Opportunities exist for developers to leverage prime downtown locations and create value through the redevelopment of older assets. Many of these opportunities present complex challenges that require incorporating modern design, technology and environmental strategies into structures that were built more than 30 years ago. The most successful projects involve teams that begin with a holistic approach and a sense of how best to balance priorities, especially when project goals present conflicts.
Such was the case in the redevelopment of 1200 Nineteenth Street by the Washington, D.C. office of Hines, an international real estate firm. The developer brought in architectural team member SmithGroup, because of its established expertise in retrofitting older buildings for current conditions.
The original 1960s, 245,000- square-foot office building was well-located on a prominent corner site in D.C.’s Central Business District in a neighborhood that had been rezoned for increased commercial density. The full-building redesign added 90,000 square feet on three new floors, and transformed a B-quality building into a trophy-class asset. In addition, the building earned an Energy Star® score of 99 (out of 100) and enhanced the existing street-level retail.
Before photo of 1200 19th Street.
After photo: A structural steel framing system enabled the owner to add value with three new floors and minimized the amount of weight added to the original structure.
Leveraging Zoning to Create Value
In 2003, Hines acquired the property, recognizing its strong location, efficient floor plates and potential for value creation. There were many challenges with the existing building. Overall, the box-like property lacked curb appeal and identity. Its limestone façade featured rows of small, non-descript windows and an undistinguished entry lobby that was dated and dark. At street level, awnings diminished the storefronts that appeared dark and unwelcoming through windows that were too deeply recessed. The building systems were highly inefficient and all of the key office tenants were vacating the building. Leases with retail tenants required that they remain open for business through renovation.
Determined to create a signature complex in the competitive D.C. office market, Hines set the bar high for its redevelopment goals. The building was located in a neighborhood that had been designated a new Downtown Receiving Zone, affording Hines the opportunity to take advantage of transferrable development rights (TDRs), which allowed for the possibility of three floors to be added to the building.
Structural engineers, Thornton Tomasetti, determined that the existing 1960s structure could support three new floors and a penthouse by the use of a structural steel framing system. This was a critical factor. Salvaging the existing concrete structure saved almost a year on the demolition and construction schedule.
Going Beyond the Boring Box
The big-picture design challenge was how to transform a boring 1960s box into a dynamic structure. Building on conceptual ideas that Hines brought to the table, the decision was made to replace the existing limestone façade with a glass curtain wall of super-clear, low-iron glass, which affords a subtle reflectivity and sheen. To create scale and visual interest, the design featured three distinct zones: the retail base, main entrance and a modern cornice set off-center. The glass façade was designed as a series of asymmetrical planes. It featured a darker, more reflective top floor contrasted with less reflective layers for the lower façade of the building. The roofline – once flat and uninspiring – was designed to angle gracefully above the streetscape. A sunshade wraps the entire top floor of the building, reducing heat gain and creating an interesting visual expression as a modern cornice.
Identity and rebranding programs to enhance the streetscape included new signage, custom lighting, enlarged storefronts and sustainable landscaping.
The curtainwall was designed as a unitized system, which provided the ability to observe development details as the units were being fabricated. A glazing subcontractor was brought into the project during the early stages of design to help engineer a system that could be fabricated and installed quickly. Pricing determined many of the components in the curtainwall system such as mullion finish, sill and glass. The system design was modified to achieve the clean look of recessed caulking without the higher cost of a dry sealed system. The exterior details were achieved through modifying the standard mold to produce fins and channels on the glass.
SmithGroup specified a low-iron glass with a low e-energy coating to maximize the transparency, views, and access to natural light in the interior, while minimizing the energy loss through heat gain – all important aspects of sustainable design.
As with any major repositioning of an older building, the structure did not conform 100 percent to the original drawings. This was a particular challenge when it was discovered that additional concrete demolition of the beams was required. Six rear perimeter columns were reinforced with steel and additional concrete to address seismic issues that were not code requirements in 1964 when the building had been completed. Select portions of the concrete structural slab were reinforced with carbon fiber to address additional live load on the existing roof, which would become an occupied floor following the addition of 90,000 square feet above. General Contractor Clark Construction Group, LLC was able to have the steel structure fabricated and installed during the demolition of the exterior façade and the interior renovation.
Designing a Focal Point
Before photo of the lobby.
After photo: The entrance lobby contrasts modern materials such as stainless steel and back painted glass with Portuguese limestone and FSC-certified red oak.
Creating a lively, functional streetscape presence and defining a once lack-luster building entrance were integral requirements that the redesign captured successfully. The majority of the ground floor incorporated retail uses and the tenants remained open during 20 months of construction. During that time, the awnings were taken down, and replaced with larger storefronts of clear glass accented with illuminated channel signage. Adjacent to the storefront retail, 20-foot wide sidewalks were redesigned to include a sustainable garden and feature recycled granite (from the original building) and locally-sourced rough cut granite. Other improvements to the streetscape included the addition of cobblestone pavers, bicycle racks and a lay-by. Indigenous trees were planted within attractive tree boxes providing shade for outdoor restaurant areas. To reduce storm water run-off, a critical issue in downtown Washington, D.C., a four-foot swatch of pervious granite pavers was constructed along the entire street curb.
The main building entry, once difficult to locate, was offset with a strong angular exterior glass canopy. It mimics the building’s asymmetrical design through a projecting prow, which is slightly offset from the center. The new building lobby was designed with a mix of contrasting, contemporary materials. The concept created a sleek, minimal lobby reflective of the building exterior, but also contrasted with natural, warm materials. Walls feature Rhino white marble from Africa and a white, back-painted glass supported by similar stainless steel connections featured on the exterior entry façade. A Portuguese limestone floor is complimented with warm acoustical ribbed ceiling panels in red oak. The elevator lobby wall is clad with sustainable Forest Stewardship Council (FSC)-certified red oak panels and stainless steel trim that replicates the façade trim. The intent to have a part of the lobby function as art, in place of a commissioned piece, was realized in a large panel of silk-screened glass reflecting a modern snowflake pattern.
Sustainable Strategies Earn Efficiencies
Working closely together, SmithGroup, MEP Engineer Tolk and sustainability consultant BVM Engineering successfully achieved many of Hines’ sustainable goals for the building, including providing employee comfort and limiting negative effects on the environment. Tolk designed a high-efficiency, floor-by-floor mechanical system that included rooftop chillers modeled to achieve a 64 percent reduction in carbon dioxide emissions. The toilet rooms were designed with low-flow faucets, sensor controls and dual-flush toilets to reduce potable water consumption by an expected 38.7 percent. The building materials throughout the project were selected to reduce volatile organic compounds emissions. Atop the building, an intensive green roof reflects heat from the building and provides magnificent landscaping for a rooftop terrace amenity that enjoys stunning views of the Washington Monument, National Cathedral and other landmarks.
Hines incorporated a stringent program of enhanced commissioning that ensures the building systems continue to perform at their highest efficiencies. In December 2008, the building was pre-certified LEED Silver for Core & Shell. Based on the sustainable energy strategies, Hines anticipates that the reduction of greenhouse gases is equivalent to annually removing almost 600 passenger vehicles from the road.
1200 Nineteenth Street re-opened during the second quarter 2009, and McKinsey & Company, Inc. moved into its new offices on the top three floors in November 2009. The efforts of Hines’ team to create value, retain the best of an older structure and provide a modern, sustainable environment illustrates that there are proven strategies that can attract top tenants and help guide complex, sustainable redevelopments regardless of a building’s unique characteristics.