One Size Does Not Fit All: Cambridge Affordable Housing Development

In the Cambridge’s  proposed Affordable Housing Overlay (AHO) the increased height and Floor Area Ratio (FAR) called for will impact neighborhoods in strikingly different ways. For example, up to 94% of buildings in zip code 02138 are two to five times smaller than the proposed 2.0 FAR and 1 to 3 stories shorter than the proposed height limit.[i] This will ultimately make such properties, previously considered as homes for working class and middle-income families, attractive development targets.  The scale of buildings can be categorized into five different groups based on FAR and lot coverage. The below graphic succinctly illustrates the scale of each level of development intensity, as well as the potential negative impacts of unrestrained development “as of right” in every neighborhood, without normal rights of legal appeal

Map Below: Targeted sites in each zip code for 40 unit, 4 story tall AHO projects comprise very property over 10,000 SF. Properties between 5,000 SF and 9.99 K SF could be combined or used as is for 4 story projects with fewer units. FAR of 2.0 Impacts: Using Cambridge examples from the 02138zip code, the largest of Cambridge’s five zip codes with 3318 structures, reveals how changes to FAR limits can impact neighborhood density dramatically.

​The map above shows the likely target area for larger Affordable Housing Projects (40 unit, 4 story structures). Here is a clickable map, you can see the buildings areas when you zoom in: 
https://www.google.com/maps/d/u/0/viewer?mid=1XVdaCmcmz4_l9jFo187U1YVUkN7b5rrx&hl=en&ll=42.37762733165042%2C-71.12497354128416&z=15
The light lavender background is the 02138 zip code where most of these large developments are slotted to occur also will be impacted far more because currently these properties have far LOWER FAR (density, Floor Area Ratio) then elsewhere in the city and a building with a 2.0 will represent a massive density and scale change here. See the graph below for the large differential impacts of a 2.0 FAR on the cities key zip codes. The lower the graph differential the more naturally a 2.0 FAR would fit in.

An FAR of 2.0 is universally reserved for large urban densities,  not for other types of residential areas as the comparison below indicates. Key parts of residential Cambridge do not meet the criteria for 2.0 FAR found in other places like New York city, Mumbai, or outlying areas of Paris.

Let's look now at the FAR context of specific Cambridge neighborhoods in 02138 where these large AHO Developments are targeted to be built. As we can see below some of these large projects would dramatically impact a local neighborhood.  

Group 1 (above): 0.20 to 0.49 FAR (410 structures) = 12% of buildings in 02138. These are primarily small 1 and 2 story structures on streets where the proposed 2.0 FAR for affordable housing up-zoning can be 4 to 10 times larger than the massing of current structures, with up to 40 new units replacing existing smaller homes.
 

Group 2 (above): 0.49 to .99 FAR (1421 structures) = 43% of buildings in 02138. Mostly 1, 2, and some 3 story, single & two-family residences where a 2.0 FAR will mean 4 story structures (often double the height) and 2 to 4 times the massing of current structures.
 
Increasing FAR allowances for Groups 1 & 2 to 2.00 FAR, allowing 4-story heights, and permitting 40-unit capacities would be a massive increase in density and height for most residential streets in 02138, radically transforming these areas, whether it be for market rate or affordable housing.

Group 5 (above): 2.00- 2.99 FAR (circa. 122 structures) = 4% of buildings in 02138. Selected above are 4 story affordable housing developments similar to those being proposed city wide. Most FAR 2.0 buildings in 02138 are 3-5 story, 9+ unit apartment buildings in very dense settings, largely reserved for commercial or institutional uses.  
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Disparities between the locations of current AHO developments and available properties elsewhere. Many targeted sites are located in the city's most expensive properties in part because these were the least urbanized parts of the city . These larger properties also have the largest proportion of large trees. Some are historically protected. So units placed in these areas not only become very expensive to build - increasing the costs of each unit dramatically and making fewer available, but also in some cases more impactful on the environment.

The larger properties appropriate to the large 40 unit AHO developments disproportionately fall in one city zip code: 02138. Since the AHO petition is "as of right" removing any oversight from citizen groups such as the Planning Board and removes any ability of citizen appeal this makes one of the largest areas of the city feel the impacts of this decision disproportionately to other zip codes.

The graphs below show properties 10,000 SF and larger and their locations in zip codes around the city. By far the largest number of these Affordable Housing projects (roughly 87%) in Cambridge are being targeted for  properties in the 02138. zipcode.

While the potential AHO locations based on size are somewhat  more widely distributed for 5,000 SF Cambridge properties and larger, still 02138 remains the disproportionate target.

What can be done now to add more Affordable Housing more equitably and in ways that will bring MORE of these units to the city and will have impacts more evenly distributed. There are many possibilities including focusing these large scale developments on the major corridors as Urban Planning guidelines have long proposed and through strategic zoning and other changes enabling neighborhoods in 02138 (and elsewhere) to introduce more affordable housing within the framework of the current housing infrastructure. 

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Conclusions: Sensible limits on both FAR and height in neighborhoods with predominantly 1 and 2 story homes can help moderate  impacts of the AHO, while still allowing room for new growth and development. Along with key zoning changes in the Donovan Petition we will be able  to add far more to our affordable housing in this city and at less steep financial, environmental, and other costs.