Recently Eric Herot tweeted some images from his neighborhood of Jamaica Plain, showing how Boston’s zoning laws mean that the parking required for triple deckers takes up enough space to build another triple decker. The buildings that comprise the majority of the housing stock of many neighborhoods and have provided generations of Bostonians with affordable housing (this is being written in a triple decker in Cambridge).
But while parking requirements do drive up housing costs and waste land that could be better used for just about anything, triple deckers have an even bigger problem: themselves. In Boston many were built during the City’s first great building boom, between 1890 and 1914. They were built of wood along streets designed to feed into the expanding street car network and they were sold as a unit. Usually, and this still happens, the first floor would be occupied by the owner’s family and the second and third would be rented out to pay off the mortgage or provide an income.
At the time, not only were families bigger, on average, than they are now, but buying a triple-decker was as much an indication of social advancement as addressing a housing need. As a result of wood construction and social climbing, the typical triple-decker is big.
Really big. According to Zillow, the median price per square foot in Boston is $530. The typical triple decker runs about 1100 square feet a floor, so excluding land costs, that’s $583,000 per unit. In addition to being bigger than many suburban houses in terms of lot coverage, the lots they are on are also commonly huge. It varies around the City, with around 3400 square feet common around Forest Hills and some Dorchester triple deckers are on 4000 square foot lots.
While those are a far cry from the quarter-acre lots of recent suburbs, it still represents a signifigant amount of land. Absent the zoning restrictions that lock in the form and uses of a neighborhood, small, incremental developers could add quite a bit of housing and retail space in many lots now home to triple deckers.
South End rowhouses are usually on 1100 square foot lots and the apartment buildings of the Fenway and Allston are often on 4000 square foot lots and up. There’s so much land locked up by triple deckers that a substantial increase in density could be made without any increase in height or massing. There’s a lot of nostalgia invested in them — there’s probably no one in Boston who hasn’t lived in one at one time and there are still plenty of families left who got a measure of security from buying a triple decker and paying off the mortgage from renting two of the floors. Realisticly, that’s impossible now, but the memory is powerful.
But the zoning rules and absurd process make working at such a small all but impractical. Political will for change is in even shorter supply than housing.