One of the many ways mobile and stationary homes differ is that, short of rigging some kind of sidecar, there’s no way to enlarge a travel trailer. Oakland-based architects Cheng+Snyder encountered this dilemma when they were hired by engineer Gregory Piche to make a streamlined 1961 trailer livable for a family of three. With only 112 square feet to work with, it was a tall order for the architects, but principals Irene Cheng and Brett Snyder had an idea.

By installing a fold-out wall, they transformed the main room into what Snyder calls a “balcony on wheels.” When the wall is up, it contains a sleeping bunk and storage unit; when it’s down, it functions as a dining surface and allows the family to extend their activities outdoors. With other space-efficient features, like storage cubes that double as seats and a drop-down table, the home is able to accommodate a walk-in shower as well as workspace for Gregory.

The trailer’s eco-friendly credentials are impressive, too. Rooftop solar panels and a backup propane system power modern appliances, including a furnace, refrigerator, microwave/convection oven, stovetop, and hot water heater. The result is a rolling residence that is a paragon of both space and energy efficiency.