In San Francisco, the comparatively chilly maritime climate often calls for wearing an extra layer, even in the summer. This goes for buildings too. For the recent renovation of a 78-year-old hybrid commercial and manufacturing facility in the city’s Design District, Pfau Long Architecture inserted an operable glass roof above a new warehouse atrium that can be that extra layer when the weather is cool or rainy but be opened on warm, sunny days. This light-filled, permeable space is a transformation of what had been a relatively utilitarian structure, and still honors its industrial nature.