Philadelphia, like many eastern US cities, has lots of brownstones. I’ve explored this form before as an example of strong composition in architecture, where every element contributes to the whole and no space or stylistic detail is wasted. But whereas most brownstones are huge and highly unaffordable (think Boston’s Back Bay or Brooklyn’s Park Slope), Philly has a sizeable number of rowhouses in miniature.

Originally built in the 18th century to house servants, the trinity houses are so-named because they contain three main rooms, stacked one over the other. A bedroom (with a tiny bath) stands over a living room, which in turn stands atop a kitchen on the ground or garden level. Sometimes a fourth floor houses a second bedroom or office. A cavernous enclosed spiral stair connects the floors, though some modern homeowners have replaced them with open spirals.

Inside a trinity house. (Philadelphia Magazine)

Most trinity houses are built in alleys between the square city blocks. The off-street locations enable car-free common spaces and private yards. Many such neighborhoods are in the heart of the city, where other housing options far exceed the price range of most residents.

When Philadelphia Magazine asked readers to describe their experiences living in a trinity house, they received a spectrum of responses. Some residents praised the affordable downtown living, the energy savings, and the liberation caused by forced minimalism. Others bemoaned the constant stair-climbing, the difficulty of moving furniture, and the inability to host large gatherings. Trinity houses are not for everyone, but they’re a fantastic option to have. If only more cities could offer the same.

Thanks to Josh Bonaventura-Sparagna.