NyrenHaresign_1_150In his 34 years as an architect, David Haresign estimates that almost half of his work has involved restoration or adaptive use. That includes converting a historic school into condos, an old department store warehouse into a speculative office building, and an airplane parts warehouse into an office building for America Online. A partner at Bonstra | Haresign Architects in Washington, D.C., and a ULI member, he shares some key lessons from his experience.

Q: What should developers know before embarking on adaptive use projects?

The key thing is to understand the existing building in every way possible. That includes contextual constraints, such as zoning requirements and use limitations, and legal constraints. Also the physical context. Sometimes people buy industrial buildings in edge neighborhoods—you have to make sure you are not pioneering too much.

You need to understand the condition of the building. Buildings constructed at the turn of the 20th century often have a brittle concrete structure. You can’t assume that they can take on an additional structural load or even handle the current load.

Q: What makes a building suitable for adaptive use?

An older building may not lend itself easily to all uses—it may not have the ideal building depth or layout for residential units or office space. Sometimes buildings built in the 1950s or later are more easily molded and modified than older structures, because they are generally made of lighter-weight materials. For the Creative Center 1 in Dulles, Virginia, America Online acquired an airplane parts warehouse that was less than 10 years old, with a very wide footprint—about 450 feet by 270 feet (137 by 82 m) at its widest points. You wouldn’t think of that as an office building, but by dropping atria light wells through the center of it, we were able to make it more like a typical office building, so people were never more than 40 or 45 feet (12 to 14 m) away from light. Everything depends on the building and its adaptability.

NyrenHaresign_2_300Q: What about the costs? How do you evaluate whether an older building is worth adapting?

Adaptive use may save money for basic structure, and it may save time. It costs more in terms of fees for professional services and project management. The older the building, the more investigation the design team has to do. Selective demolition may be needed to investigate what’s behind those old walls.

Sometimes you just don’t know until you actually get into the project. For Parker Flats at Gage School in Washington, D.C., the conversion of a historic school into condos, we thought we were going to be able to save more of the roof joists. But it had a metal roof, and most of the rafters had been destroyed by heat. We couldn’t see that when the building was purchased or even when we were doing field investigation, so we’d estimated that we would have to replace about half of the roof structure. We probably ended up replacing 80 percent.

We tell our clients that on a new building, their contingency needs to be about 3 to 5 percent of the hard costs. For renovation work, it depends—for a newer building, 5 to 8 percent is probably enough. For an older building, the contingency may need to be as much as 10 or 12 percent.

On the other hand, when you adaptively use an existing building, you don’t have to pour a new foundation or build the structure. Even if you have to strip it back to the skin, you are starting with something. I’m a big believer in adaptive use and renovation.