This is the sort of housing project that you'd fully expect to find in Tokyo. Seven homes built on a small urban lot measuring only 11 feet wide by 93 feet deep. But in this case, it's not Tokyo; it's Chinatown, Philadelphia, where a residual lot that was created when the sunken Vine Street Expressway was carved through the middle of the city in the 1950s.

Designed by Philadelphia-based Interface Studio Architects (ISA), the project contains 7 levels of livable space. What's interesting, though, is that from a building code perspective this is still a 4-story building. There are two mezzanine levels that don't get counted (and that create some great double-height spaces). This also seems to be what allowed them to get away with a single egress stair in the middle of the building.

The other technique that was used to maximum density is facade projections. Philadelphia's zoning code allows for projections up to 3 feet in the horizontal dimension. And if you look at the above plans, you'll see that these were used to "top up" or extend the site's 11 foot width to 14 feet, when it made sense to do so from a programming standpoint. The result is some very livable spaces.

I am endlessly fascinated by these sorts of projects because they demand creativity and because you ultimately end up unlocking something that the market had been overlooking. Here is an example of a small leftover urban parcel that was previously used as surface parking for two cars. Now it's seven beautiful homes.

Photos/drawings: ISA