Supply Meets Demand: Converting Office Space to Multifamily

WASHINGTON, DC-In a competitive job market, employers pay close attention to workplace trends that might help them attract and retain the best talent. Finding office space with natural light and a flexible layout allows companies to design an environment that will prove attractive both to employees and to potential clients. As new offices with shiny amenities that meet these needs come to market, many older buildings are passed over despite their prime location. Building owners are faced with difficult decisions on what can be done to make these properties more productive, a prospect that often requires substantial renovation or outright replacement.

Adaptive reuse can optimize the operational and commercial performance of a building by transforming obsolete spaces to serve entirely new purposes. When office vacancy rates are elevated and urban housing is scarce, refitting less competitive office buildings for residential use can eliminate both problems with a single solution. While it's not the right answer for every property, these conversions can potentially meet a real market need on a considerably faster timeline than demolishing the old building to make way for entirely new construction.

Structural Challenges

Some of the same factors that make a building attractive for office use can present challenges to designing an appealing residential community. A typical older office building is 240 feet long and 120 feet deep with a rectangular central core for mechanical, electrical, restrooms and elevator support. In comparison, a standard double-loaded corridor in an apartment building is only 65-70 feet deep. Placing apartments along the perimeter windows of the office building and then stretching them to line up along a central hallway would create uncomfortably deep apartments without any natural light in the inner rooms. Reducing the depth of the units by adding additional corridors leaves a considerable footprint of internal, windowless space without a straightforward purpose. Finding ways to utilize this inner core efficiently can be a determining factor in deciding if residential conversion is a good fit.

In a recent project at 200 Stovall St., a design team from Cooper Carry decided to dedicate this interior space to resident amenities. Tapping into a strong market for off-site storage unit rentals ubiquitous in cities, they envisioned dedicated storage areas on every floor where residents can tuck Christmas décor and empty suitcases out of sight when they're not needed. Thinking about the services and lifestyle interests of busy professionals, they also incorporated conveniences that can save residents time and travel to accomplish other tasks. The building boasts a three-level gym, movie-screening room, double-floor sports bar with golf simulators and video gaming equipment, a pet spa and dog run, co-working/workshop areas, and a rooftop pool deck and outdoor entertainment area.

The multi-floor design of some of these features boosts the number of units in direct proximity to the most desirable amenities and allows the building management to diversify offerings and consolidate maintenance efforts – overseeing a single multi-story gym with a range of exercise equipment instead of three separate areas with identical banks of treadmills, ellipticals, and spin bikes.

Spanning multiple floors does involve removing portions of the slab between floors, requiring careful design to ensure that the building's structural load is adequately distributed to the existing foundation system. The feasibility of such changes depends on the availability of original architectural drawings or other accurate information about the building's design and engineering. In the areas where a slab is removed, the two sets of 10-foot tall columns that supported it originally essentially become a single set of 20-foot tall columns and subject to a whole new set of code requirements for safety.

At 200 Stovall, the developer also decided to incorporate on-site parking. This added value to the building along with some additional technical challenges. Since they wanted to retain the street level retail space and digging below an existing building would have been impractical, they converted a number of the original office floors above the lobby into parking, with ramps for access, open walls for ventilation, and careful waterproofing to prevent damage to the space below.

Lest we only focus on the challenges, we should mention some of the ways older office buildings are well-suited for residential conversion. The 10-foot floor to floor height ceilings that were common in older buildings might not make for lofty office space, but they are taller than those in many residential units. Some developers choose to expose the structure for even more volume and an industrial feel. At 200 Stovall, the architects and engineers determined that the foundation could support an additional three floors, so those were added to the top of the building to maximize the site's efficiency. The decision to re-clad the building's exterior also gave designers the opportunity to set some of the deeper in the façade to make room for small balconies in some of the units, adding visual interest to the façade and a nice feature for tenants.

Another upside to a renovation is that as the project progresses, leases can be staggered as individual floors are completed. This means fewer agents and less real estate in the lobby devoted to leasing at a single time. With this leasing pattern in mind at 200 Stovall, the lobby plans included a leasing office located within the building's co-working and conference space, adjacent to the building's food hall and lounge areas for a more communal atmosphere. With 5,200 residential units in the building, staggered leases allow for more gradual turnover and steadier management.

Adaptive Reuse

Being able to modify an older building for a new use significantly reduces the time a building languishes in construction without offering owners a return. It is also the greenest option of what to do with an unmarketable building, eliminating much of the debris that might otherwise be headed for the landfill if it were instead demolished for replacement with new construction.

Of course, with an older building also comes older building materials. The mechanical, electrical, and plumbing systems of a 48-year-old building have almost certainly outlived their usefulness and will require replacement. Sometimes the discovery of asbestos in the tiles or the ductwork insulation of a building adds complications, underscoring the need for owners interested in adaptive reuse to do due diligence before embarking on a renovation.

With a new purpose, the reimagined building will also require new zoning. Close cooperation with municipal officials and the owners and occupants of neighboring buildings throughout the process can defuse potential difficulties in changing the building's use. With the growing rate of buildings unable to compete for market-rate office tenants, adapting from a homogenous jungle of office buildings to a neighborhood with a range of uses may even require more dramatic reconsideration of traditional zoning distinctions to accommodate a modern mixed-use urban character.

As office vacancies in older buildings increase and the housing market remains strong, the potential for adaptive conversion of offices to multi-family residential properties becomes increasingly more economically viable. Though not every building is well-suited to such adaptation, careful planning and creative design can facilitate a transition to a more efficient and productive use of older properties.

Steve Smith, AIA, is a principal at Cooper Carry.

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