Key Takeaways
⇢ High‑density does not require high‑rise buildings. Well‑designed two‑ to three‑story ‘house‑scale’ buildings can achieve 60–90 units/acre.
⇢ Missing middle works best within a 5–10 min walk of a main street — population densities of ~8,000–11,000 people/sq mi support shops, transit, and social life.
Summary
a. The house‑scale multi-unit forms like duplexes, triplexes, courtyard buildings, and cottage courts were once ubiquitous but have been outlawed by a century old traditional U.S. codes and zoning systems.
b. Over 50% of U.S. households prefer attached housing (townhomes, small apartments) if coupled with easy walking access to shops/restaurants.
c. A rapid “Missing Middle Scan” (mapping + fieldwork + code review) can guide cities to target neighborhoods for reform in ~3 months.
d. Opticos’ projects that transformed mid-rise housing into mainstream walkable neighbourhoods:
○ Urban Waters (Papillion, NE – Omaha Metro): a series of buildings in a walkable neighborhood pattern that look like a larger single family home, but actually have five, six, seven units within that building.
– It behaves and functions like a single family neighbourhood but it delivers that in a missing middle or a plex building type.
– Despite a dependent context and heavy snowfall, Opticos provided only 1 parking space/unit, in addition to on‑street parking.
– With spaces for cars and for people and communities, the project generated high resident satisfaction.
○ Halsell Builders (Santa Maria, CA): city removed density caps enabling the developers to deliver a 3-storey courtyard building with 120 dwelling units/acre.
○ Culdesac Tempe – Car-free living (Arizona): a pilot project that demonstrates there is a demand for car-free living.
– 636 dwelling units, 21 local businesses, and zero parking spaces for residential use.
– Climate-responsive design with buildings shading each other and no asphalt use to avoid heat gain.
○ Sacramento Zoning Reform: city removed density caps and introduced sliding‑scale FAR incentives (more units = more allowable square footage).
How can Cities in North America apply these learnings?
We need interventions that deliver diverse, attainable housing in walkable neighborhoods, cut car dependency, and support low‑carbon, socially vibrant communities:
a. Amend residential zones to allow 2–6 unit house‑scale buildings:
○ Conduct GIS + field surveys to identify 5–10 min walk‑sheds with schools, parks, shops ready for “missing middle” infill.
○ Graphically model existing zoning metrics vs. target typologies to spot dimensional barriers (lot width, setbacks, parking).
b. Conduct a Missing Middle Scan: map walkable nodes, audit codes, and create zoning amendments with a 3‑6 month reform road‑map.
Interesting resources
a. Washington State Department of Commerce ‘Missing Middle Housing Toolkit’. https://www.commerce.wa.gov/growth-management/housing-planning/middle-housing/
b. AARP & Opticos Guide: Discovering & Developing Missing Middle Housing. https://www.aarp.org/livable-communities/housing/info-2022/missing-middle-housing-download.html
c. Resilience Matters: Ten Years of Transformative Thinking, edited by Laurie Ann Mazur (Island Press, 2025), includes “Why Missing Middle Neighborhoods Are the Sweet Spot Between the City and the Suburbs”. https://islandpress.org/ten-years-transformative-thinking
d. NAR Community and Transportation Preferences Surveys. https://www.nar.realtor/reports/nar-community-and-transportation-preferences-surveys
Ideas for further reading
a. Missing Middle Housing: Thinking Big and Building Small to Respond to Today’s Housing Crisis – Book by Daniel Parolek.
b. Urbanism in the Age of Climate Change – Book by Peter Calthorpe.
c. Sacramento Adopts One of the Most Progressive Missing Middle Strategies in the U.S. by Dan Parolek. https://opticosdesign.com/blog/sacramento-adopts-one-of-the-most-progressive-missing-middle-strategies-in-the-u-s/
