Can building design reduce opposition to housing density?
A new study found several design tweaks that made suburban residents more likely to accept denser development — to a point.
High-demand metro areas face soaring housing costs largely because there aren’t enough new homes to go around. In response, some local governments are embracing policies that make it easier to build more homes in existing inner-ring suburbs, with California implementing two such laws just last week. But resistance to denser suburban development can be fierce, leading to political and community tensions that preserve the status quo.
In London, this very trend inspired a group of researchers to ask a question: Could thoughtful housing design help overcome the opposition to suburban housing density? The new work, published online last month in the journal Urban Studies, suggests the answer is a heavily qualified yes, but. While certain designs made low densities (three stories) significantly more acceptable, the effects waned at medium (six stories) densities and all-but disappeared for high-density buildings (nine stories).
Still, the research team sees a glimmer of hope in the results, since even the lowest densities would effectively double the density found in most London suburbs today. They conclude:
It is important to note that our low density proposition is still considerably higher than typical existing suburban densities and so, if made more acceptable by design, it could contribute to significantly increasing housing density in the suburbs. … Thus, design can make a difference in promoting density that is higher than the existing suburban fabric.
To reach that conclusion, the researchers conducted an online study of more than 900 suburban London residents in early 2020. Study participants saw a randomized photo series of 24 housing developments, which they were told to imagine would be built within a 10-minute walk of their own home. Some of the photos showed current London housing developments; others showed design adaptations of these same developments, with changes made to things like building setback, parking supply, facade material, roofing, and public greenery.
The random photo series cut across three different density tiers: low, medium, and high. For some photos, study participants rated their perceived density of a development (from very low to very high). For other photos, they rated how acceptable they found the density level, from 0 (completely unacceptable) to 10 (fully acceptable). Here’s what they found:
Unsurprisingly, acceptability declined as density rose. Consistent with real-world trends, the researchers found a strong correlation between the perceived level of density in a picture and acceptability for that density to exist nearby. People accepted having a fairly low-density neighbor, but as perceived density rose, the acceptability scores fell.
Several design changes made low-density buildings even more acceptable. Low-density buildings were generally more acceptable than taller developments, but a number of design tweaks made some three-story buildings significantly more acceptable than others. These treatments included brick or wood facades (versus steel), more window coverage, larger green spaces, pitched roofs (versus flat), and no parking. The researchers believe these particular features reinforced a classic “village green” suburban feel.
Only a couple designs made medium-density buildings more acceptable. Most design changes failed to make a difference on how study participants felt about six-story developments, but a couple moved the needle. Brick finishes (and to a lesser extent wood) significantly improved acceptability over steel facades. Abundant private greenery (and to lesser extent large public spaces) also made for significantly more acceptable ratings.
Only one design feature improved high-density acceptability. When it came to the nine-story buildings, the only design intervention that significantly increased acceptability was a pitched (versus flat) roof. Pitched roofs might have given off a single-family suburban feel, whereas flat roofs perhaps conjured public housing blocks. Even with the pitched-roof bump, high-density acceptability only rated around a 5 out of 10.
The big caveat here is that it’s far easier to accept a picture of a development than an actual one. Still, the good news is that design may have a meaningful impact on opposition to low-density buildings that nevertheless represent a significant increase in housing supply. The bad — if not surprising — news is that design had a “diminishing effect” on the acceptability of greater densities, with virtually no impact on high-density housing.
There was one more bright spot from the work: the impact of attitude. In assessing general attitudes about housing, the researchers found a strong connection between participants who agreed strongly that “London has a housing crisis” and acceptability of density across all building levels. In fact, the effect size of that attitude on acceptability was greater than any single design treatment.
This finding suggests the importance of tackling housing opposition across several fronts — “with design being just one,” write the researchers, and public urgency being another. A few other promising fronts are also emerging.
One is the rise in suburban renters. In London, home-ownership rates fell from 68 percent in 1991 to 62 percent in 2018. In the U.S., renting is becoming more common in the suburbs, with some developers even moving to “built-to-rent” models. While this trend does have some worrying equity implications, making the wealth generated by homeownership less accessible, one silver lining for density advocates is that renters generally have less reason to oppose denser housing on the grounds of protecting home values.
Technology can also play a role. The suburban participants in the current study expressed a clear opposition to steel structures, which may have reminded them too much of the types of buildings found in downtown areas. The use of a new construction material like sustainable mass timber for mid-rise buildings could ease the transition into denser suburban environments.
Finally, the pandemic may change some minds. While people didn’t flee cities en masse, many residents did move to other parts of a given metro area. Households that made an accelerated exit from city centers may well seek a more urban lifestyle than the traditional suburbs provide, reducing opposition to — and perhaps even encouraging the creation of — denser mixed-use developments.
Maybe in time the classic suburban feel will be less about a “village green” and more about an “urban village.”
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