Spotlight on Zoning Practice

Harnessing the Power of Patterns for Zoning Reform

As noted by many neuroscientists, philosophers, and psychologists, humans are pattern-seeking animals. Patterns help us make sense of the world, and arguably, our affinity for patterns underlies the widespread application of Euclidean zoning and its strict separation of uses. But when used at a different scale and in a different way, patterns may also help us diversify and expand the supply of housing in our communities.

In sewing and other handicrafts, patterns can speed the process of replicating desirable objects. Similarly, architectural pattern books can speed the process of reproducing desirable buildings. In the January issue of Zoning Practice, "Pattern Zones and Pre-Reviewed Homes," Richard Murphy, AICP, outlines the key features of a pattern-book-based approach to zoning and explains how this approach can complement other efforts to promote missing middle housing.

Foundations of a New Pattern Approach

As Murphy explains, a pattern-book-based approach to zoning is rooted in three foundational concepts: pre-reviewed plans, the pattern book, and pattern zones. Pre-reviewed plans are sets of reusable housing construction plans that have already been vetted by local officials, which takes the guesswork out of permitting processes. The pattern book is a collection of pre-reviewed plans available to potential home builders. Pattern zones are zoning districts where specific pre-reviewed plans are permitted by right.

As Murphy notes, this approach has many direct antecedents, ranging from the mail-order houses of the early 20th century to Christopher Alexander's influential book A Pattern Language to the increasingly widespread adoption of prescriptive form controls in contemporary zoning codes. The distinct advantage of a pattern-book-based approach is its scalability. You can start as small as a single pre-reviewed building plan, permissible by right in a single zoning district, and, if desired, expand to a communitywide (or even regional) optional form-based code.

Making Good Easy

According to Murphy, the core philosophy behind pre-reviewed plans is to make the housing the community wants that's easiest to build. This stands in contrast to conventional proscriptive zoning that tries to eliminate every undesirable thing, without asserting an affirmative vision for desirable development. It is more flexible than an orthodox form-based code, which specifies a somewhat prescriptive vision for all permissible built forms.

Murphy says this approach is especially beneficial for communities who fear the unintended consequences of widespread upzoning. Pre-reviewed plans that are rooted in local architectural styles or that mimic the scale and massing of existing homes can alleviate concerns about integrating missing middle housing types into established neighborhoods. Local officials can also use a pattern-book approach to zoning to incentivize more energy-efficient or physically accessible residences than are required under local (or state) building codes. Perhaps most importantly, when successful, this approach can be a proving ground for additional zoning reforms by providing community members with proof of concept.

Pattern Zones and Pre-Reviewed Homes

Each issue of Zoning Practice provides practical guidance for planners and land-use attorneys engaged in drafting or administering local land-use and development regulations. An annual subscription to ZP includes access to the complete archive of previous issues.

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About the Author
David Morley, AICP, is a research program and QA manager with APA and editor of Zoning Practice.

January 12, 2024

By David Morley, AICP