Zoning + Small Units

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We attended a great panel discussion at the BSA entitled “Designing Boston: Parochialism vs Production”.  Moderated by Michael P. Ross, the panel was composed of three City of Boston councilors: Bill Linehan (District 2), Frank Baker (District 3) , and Tito Jackson (District 7).  With a starting point of how the City of Boston can do more to encourage the development of affordable housing both for lower and middle class residents, the discussion was far-reaching and informative.

One topic was zoning, both in terms of how to better streamline the approvals process and how to use zoning regulations to shape the growth of affordable housing for the City.  In the words of Bill Linehan, “Zoning is key to stabilizing development going forward.”  The role of zoning, when coupled with an increasing need for one-bedroom and studio housing units, is an interesting one.  While there is support for small units, the current zoning often makes the creation of a building with many smaller units, as opposed to a building with fewer larger units, difficult.

Take the neighborhood of Roxbury as an example.  For our work on the Housing Innovation Competition, we heard that there is a shortage of studio and one-bedroom housing in the neighborhood.  According to the 2014 American Community Survey, 66% of households in Roxbury are either singles or couples and the remaining 34% of households are families of three or more.  Yet the housing stock in Roxbury consists mainly of multi-bedroom units, and only 27% of the housing stock is studios or one-bedrooms.  This has led to a situation where multi-bedroom units are being shared by multiple tenants, displacing families.


The zoning code often uses the unit as a standard of measure for how much can be built on a site zoned for residential use.  For example, the number of parking spaces and the amount of open space that needs to be provided by a building is governed by the unit.  In the Roxbury neighborhood, these requirements are the same whether it is a one-bedroom unit or a three-bedroom unit.  Utilizing the 24 Westminster site from the competition as an example, this site is zoned as 3F-4000, meaning it is designated for a 3-unit building and each unit must be provided with 1 parking space and 650 SF of open space.  With a lot size of just over 10,000 square feet and a F.A.R. of 0.8, this zoning naturally leads to large units with 3 or more bedrooms.

Per the American Community Survey, however, there is a high likelihood that such a multi-bedroom unit would be shared by multiple parties.  For example, the 3-bedroom unit could have three separate tenants with 1-2 adults per bedroom and everyone sharing the common amenities of bathroom, living, and kitchen/dining.  Recognizing these multiple tenants per unit, the parking is thereby effectively reduced to 0.33 spaces per tenant and the open space to 233 square feet per tenant.   In contrast, our project for the Housing Innovation Competition proposed many small units on the site. With our design of 10 one-bedroom units, each unit had 0.5 parking spaces and 404 square feet of open space (564 SF if the front porch and roof deck were included).  With an F.A.R. of 0.63 this structure was in keeping with the density of the neighborhood, and this degree of parking and open space is above the actual condition of how many multi-bedroom units are inhabited today.  It would, however, require a variance from the zoning code.


It is interesting to analyze and understand how the zoning code shapes our built environment.  The code creates opportunities for certain solutions while limiting the possibility of others.  As City of Boston seeks to find innovative solutions to meet the  need for compact affordable units in low to mid-density neighborhoods, aspects of the zoning code will want to be redesigned as well.