Buying an American Four- square on a tree-lined Chevy Chase street fulfilled a dream for designer Katy Anderson, who had always wanted a historic property. After renovating the home’s interiors, Anderson and her husband embarked on a favorite plan for the outside: enclosing an existing side porch and attaching a new porch in back. “I’m from Atlanta, and porches are a way of life there, a way to extend the seasons,” observes the designer. “I wanted to take the indoors out.”

Anderson collaborated with architect Christopher Snowber on the renovation, which was a challenge when it came to the exterior because of the home’s historic designation. “As with many homes that have a strong historic character and engaging details, the trick was to echo the character of the existing house without being slavishly redundant,” Snowber notes. The design team enclosed the open porch on the driveway side of the house to create a mudroom; it matches a porch on the other side that was previously converted into Anderson’s home office. Both spaces boast restored architectural details and glass expanses over the openings between columns.

A roomy screened porch replaced a small deck and slate patio off the back. It extends along the side of the house to connect with her office. With its comfortable all-weather furniture and rug, the new structure “feels like another room,” Anderson says. A wood-burning fireplace provides a focal point and curtains frame the screens. Painted-wood floors paired with walls clad in their original stucco convey a vintage look, while reclaimed-wood ceilings unify all the porch spaces.

Renovation Architecture: Christopher R. Snowber, AIA, Hamilton Snowber Architects, Washington, DC. Interior Design: Katy Anderson, Katy Anderson Interiors, Chevy Chase, Maryland. Builder: Zantzinger, Inc., Washington, DC.