The duplex where Alex Infingardi, above, lives with Miguel Martins and their dog, Sebastian, once housed a telephone company.

If you walked into Alex Infingardi and Miguel Martins’ condo, your first reaction might be, “Whoa.”

Rather than stepping into the kind of Victorian foyer you’d expect to find in a home less than a mile from the U.S. Capitol, you are instead greeted by the underside of an industrial metal staircase.

The staircase leads up to a second floor without any walls or railings to divide it from the main space. Everything on the upper floor — the office on one end and sleeping area on the other — looks out over the family room and dining area below.

“You’re pretty much almost floating when you go to sleep,” Infingardi says.

Washington may be known for stuffy rowhouses and anonymous apartment blocks, but behind some staid facades lie surprising spaces that are anything but cookie-cutter.

Whether it’s the nooks and crannies of a historic home or a sharply angled room in an ultra-modern high-rise, unusual layouts can be a challenge when it comes to interior design. Those same quirks can inspire owners to get creative, unlocking unique design opportunities you won’t find in right-angled abodes.

In Infingardi and Martins’ 1,100-square-foot condo, the open loft posed a challenge, so Infingardi, an interior designer, employed a few tricks of the trade.

The open loft in Alex Infingardi’s duplex creates some spatial challenges. He created privacy in the “bedroom,” above, by facing the headboard toward the living room.

He chose to place the foot of the bed near the back wall, with the headboard serving as a partial railing to create a cozier, more private “room,” Infingardi says.

The desk on the opposite end of the upstairs space is also placed along the open edge, providing a view of the home and windows.

Infingardi says that safety is not a concern in his railing-less loft. He can put a hand on the ceiling for balance if he needs it — it’s tall enough to stand under and yet low enough to reach.

With such a wide-open design, Infingardi played with paint colors to create the feeling of different rooms. One end of the first floor is painted a deep red to mark off the dining area, and the other end is charcoal gray to set out the family room.

“Accent walls help separate spaces,” he says.

Infingardi and Martins’ home is one of 18 units in the Telephone Company Condominiums (629 Constitution Ave. NE; 202-543-2272,, which was built in 1906 for Chesapeake and Potomac Telephone and then converted to condos in 1985. High ceilings allowed 16 units to be reborn as two-level lofts and two others as single-story condos.

On the other side of Capitol Hill, Brandon Gregoire lives in another unusual space, also in a historic building. Gregoire happened upon the Lovejoy Lofts (440 12th St. NE; 202-543-2272, in 2004 when the former school building was being converted into a 54-unit condominium. Three days later, he put an offer on an attic apartment.

One step inside tells you why.

White-painted wooden support beams run from floor to ceiling with diagonal branches reaching left and right. They form a border around the entire apartment.

“The beams turn some people off and some people on,” says Gregoire, who loves them. In addition to their look, “they help break the apartment into different zones.”

While he did the majority of the decorating himself, Gregoire brought in interior designer Tracy Morris to help with the tough stuff. “The main challenge was the ceiling pitches,” Morris says.

Because the unit was once an attic, the ceiling slants down sharply, creating unusual angles where it hits the walls.

“Most homes have a break where the ceiling starts and the wall ends,” she says, but the lines aren’t clear-cut in this place.

So Morris painted both the walls and the ceiling a neutral color. “Some designers prefer a sharp edge,” she says. “I just like it to blend in so that the place looks bigger.

In Gregoire’s home, exposed bricks play the role of accent walls. A triangular red brick wall grounds the family room and frames a window that offers fabulous views of the Capitol building at night.

When Gregoire bought the unit, it was a one-bedroom/one-bathroom with a ladder leading up to an open storage nook, but he had grander ideas.

He added a spiral staircase and moved the bedroom upstairs. Now his first floor also has a den, and his upstairs is an elegant bedroom under a sloped ceiling and a skylight.

Even newly designed buildings have units with funky shapes.

Karen Kalicka is an interior designer with clients in Turnberry Tower (1881 N. Nash St., Arlington; 703-243-3000) — a luxury condominium located near the Rosslyn Metro station.

The building is shaped like an ellipse, so many rooms have an angled wall of windows that form the outer curve.

Finding area rugs for these spaces can be a challenge, Kalicka says. The rugs either need to be smaller then the floor and set away from that wall, or “cut to mirror the shape of the room,” she says.

Also, most bedrooms in the building do not have perfect right angles — opposing walls are often different lengths. Kalicka says that furniture placement in a room like this is key. If you put the bed’s headboard along the shorter wall, it could make the room feel claustrophobic. “It’s like an optical illusion,” she says. A better choice would be to place the headboard on the longer wall.

If you can get past the challenges, there are some definite benefits, Kalicka says. “Angles add softness. They open things up, and they certainly add interest.”

After all, who wouldn’t want to live in a condo that makes visitors say, “Whoa.”