It is not quite placing square pegs into round holes but Douglas Development is fitting 39 apartments into the dome-roofed former roller skating rink above the Adams Morgan Harris Teeter.

Called the Citadel, the project exemplifies adaptive reuse -- the architectural idea of transforming industrial sites into living spaces. By preserving the 32-foot-high dome, Douglas created one of Washington's more unique apartment projects. It includes 31 units hosting large picture windows facing the city and eight interior units with only large skylights to flood the sleeping lofts and living areas with natural light.

"The product surpasses what we envisioned," said Norman Jemal, senior vice president of Douglas Development.

Units vary from 600 square feet to 850 square feet, with rents running between $1,935 and $2,590 per month, utilities included, said Jason Hogan, marketing director for the Citadel's manager, Borger Management. Residents can use a controlled access bicycle storage room and limited garage parking. Hogan expects the first leases to be signed the first week of May.

"People are amazed with the soaring high ceilings," Hogan said.

For years, the space above what is now the Harris Teeter on Kalorama Road was either vacant or underutilized. A lack of windows and the domed roof made leasing the space challenging, Jemal said.

The apartment idea formed about a decade ago when Douglas worked to bring Harris Teeter to the building. Jemal said the company waited for the market to improve before building apartments.

Adaptive reuse projects are not always easy or the best way to maximize profits, but they are rewarding, said Ed Hord, senior principal with Baltimore architecture firm Hord Coplan Macht.

"It's a very green thing to do," Hord said. "It keeps the fabric of the city."

A combination of federal, state and municipal tax credits is often what makes preserving a structure economically viable, Hord said. Without credits, developers generally opt to raze and replace old buildings.

Hord's firm has worked on several adaptive reuse projects in Baltimore, which has an abundance of underused industrial sites. In Washington, such projects are less common. With government-related office work being the predominant industry, there just are not a lot of industrial properties to adapt.

"You get some cool spaces," Hord said. "One of the secrets is you don't fight the building. Don't fight it, flaunt it."

For the Citadel's designer, Georgetown-based R2L: Architects, the secret meant embracing the dome. Large skylights and windows were cut through the reinforced concrete. R2L was confident they'd be well lit; Douglas was confident the unconventional units would rent.

Initially, R2L planned to remove part of the dome and create a courtyard, said Tom Lenar, principal at R2L. But engineers worried the structure's integrity would suffer. The building stretches 125 feet from front to back -- far too deep for conventional apartments -- so the interior units were designed, Lenar said.

Those interior units, with only skylights, attract a lot of attention, Jemal said. "People look at them and love them because they are so airy and bright."