San Francisco architect Cary Bernstein recently completed this renovation and expansion of an old cottage in San Francisco's Potrero Hill neighborhood. The cottage had suffered a series of haphazard additions over a 100-year period, and the client wanted more space and an updated modern interior. Bernstein describes her goals thusly: "To expand the house while staying within the existing footprint to protect the mature gardens, to preserve the charm of the existing building’s ad-hoc character, to integrate a modern architectural vocabulary with the older construction, and to build sustainably." The resulting home fluidly knits together a modern vocabulary of open interiors, connection to the outdoors, innovative structural details, and a mix of contemporary and reclaimed materials. For a peek inside, click though the slideshow.