If you listen to folks talk about construction in Somerville, you’ll probably hear someone complain about the size of new homes. Sometimes the complaint is that new buildings only have tiny studios for single people. Sometimes you hear that new homes are too large and too expensive for current residents. Both complaints stem from the same root: builders maximizing profit under different sets of zoning rules. So let’s look at how our zoning and economics create conditions for the contradictory complaints.
Most of the city is designated as Neighborhood Residential (NR), a zone that allows three homes in a primary building, and a backyard cottage if there’s enough room on the lot. That makes it a sensible business decision to build larger, fancier homes and sell them for more money. In other words, city regulations that limit the number of homes will lead to an increase in the size and price of what does get built.
In areas that allow more homes per lot, we see the opposite phenomenon. In general, smaller homes cost more per square foot to buy or rent but are similar in cost to build. So for any given size of building, small apartments are usually more profitable, if it’s legal to build them. That’s why we see more small apartments in project proposals like the Copper Mill proposal in Davis Square.
Of course, not everyone wants a studio, and building only one kind of home creates a variety of business risks. That’s why, even in new buildings where studios would theoretically provide the maximum revenue, there is some variation in the size of homes. For example, ten percent of the apartments in the most recent Copper Mill proposal have three bedrooms.
Similarly, not every single-family home in Somerville is destined to become a triplex, because some people will pay extra for the space and privacy of a single-family. We sometimes even see developers combine the units in 2- and 3-family buildings into extra-large singles. That’s less frequent since our zoning started to allow triple deckers by right, but it can and does happen.
Is this a problem? What should we do about it?
We can all agree that different kinds of people need and want different kinds of homes at different times in their lives. And as we have pointed out before, decades of population changes mean that Somerville needs a lot more small homes than it has. There is also a growing body of evidence that creating lots of small homes has a positive impact on the whole housing market, including people seeking larger apartments. So we don’t think it’s a problem that a lot of the city’s new apartments are on the small side.
At the same time, we want to create space for new families with children to keep our community growing and diverse. The city’s zoning code has attempted to balance these competing priorities through a zoning tool called “Density Factor,” which sets a maximum number of apartments in a new building. This allows small homes, but they must be balanced by a few larger apartments.
Home sizes are shaped by whichever constraint binds hardest: zoning rules in low-density areas push homes larger and pricier; density allowances in higher-density zones push them smaller and more profitable. The complaints seem contradictory, but they're two symptoms of the same cause: zoning rules that don’t fit the needs of the city. Fortunately, we wrote the rules, and we can rewrite them as needed.
P.S. our building codes also incentives smaller apartments due to excessively strict fire egress rules. However, the rest of the world uses different rules which allows “point access blocks” or “single stair buildings”. We are seeing movement on this issue with local, state, federal, and national support growing for reform.