When the owner of Connecticut Avenue’s grand Kennedy-Warren apartment house decided to expand the art-deco landmark, it had a ready-made way to win over local preservationists: It merely dusted off the original plans. According to the blueprints from 1931, the 300-plus-unit building in Cleveland Park was designed to be bigger than it eventually became. For the owner, B.F. Saul Property Co., achieving historical accuracy appeared to be easy. All the planners had to do was finish where their Hoover-era predecessors had left off.

But in the details, the project, whose planning and construction took eight years, was daunting. Replicating the existing exterior stone elements, such as the eagle and sunburst designs over the doors and the elephant reliefs under the windows, was difficult enough. Contractors had to hunt down the proper tone of limestone in various Indiana quarries. Plaster molds and photographs were then delivered to masons at the quarries, who used hand tools to carve the designs without ever setting foot in D.C. “If we’re off, we might be off by one-sixteenth [of an inch] or so,” says Manny Seara, the Springfield, Va., contractor who supervised the stone work.

The plans were less specific about the building’s interior, so that facet of the expansion required more interpretation than imitation. The lobby in the new wing was to be nearly as lavish as the lobby in the old wing had once been—but the old lobby hadn’t been lavish in decades. Various shades of gray masked what had once been a colorful ceiling, and all the existing photographic evidence of its original appearance was in black and white.

A little paint archaeology—microscopic analysis of flakes taken from the ceiling—uncovered the original color scheme of acid green and orange-red. The decorative painters on the job, from Baltimore-based Valley Craftsmen, however, disregarded authenticity at the behest of interior designers, and mercifully came up with a “mellower” palette, says Sam Robinson, president of Valley Craftsmen. Designers created deco flourishes inspired by existing elements in the building—such as the sunburst—and Robinson’s crew stenciled them in both the old lobby and the new.

What looks to be the most complex feature of the Kennedy-Warren expansion was actually one of the least complicated to carry out. The owners wanted something that would evoke the wood-veneer panels that had lined the lobby and corridors until they were replaced by wallpaper in the ’60s. Seeking a durable alternative to wood, they commissioned Robinson’s company to paint a couple of hundred faux-wood panels on the walls of both the old and new lobbies and the corridor connecting them.

All told, the fakes exhibit more craftsmanship than real ones could have. Each one is different from the next, the pseudo woodgrain the result of the whims of the painter and the naturalistic effects of a badger-hair brush. The trick is in the expert movement of the wrist. “You wiggle it this way, you wiggle it that way, and you may streak it a little bit,” Robinson says.

—David Morton