Missing-middle zoning could boost Denver's affordable housing supply by nearly half
A simulation of ten policy options suggests that citywide upzoning for duplexes, townhomes and similar “missing-middle” units could raise Denver's market-rate multifamily output by about 46% while cutting construction costs.
Colorado faces a severe affordable-housing crunch, with more than half of low-income residents spending over 30% of their income on housing and a shortage of over 106,000 homes statewide. To explore remedies, scholars from the University of Denver’s Center for Housing Research and Innovative Solutions collaborated with Terner Labs at UC-Berkeley, feeding a Housing Policy Simulator ten simplified policy proposals for Denver.
The model, which accounts for interest rates, zoning rules and past market trends, indicated that a citywide missing-middle upzoning—allowing duplexes, triplexes, quad-plexes, cottage courts and townhomes on any parcel with a minimum of four units—could boost market-rate multifamily construction by about 46% and cut average unit costs from $826,000 to $597,000. Policies that reduce permitting staff or enforce downzoning were projected to hinder development and raise expenses.
While the simulation highlights the potential of missing-middle zoning, the authors caution that neighborhood resistance, infrastructure concerns and political realities, such as the recent defeat of a similar reform in Lakewood, could limit actual outcomes. They argue that combining zoning changes with other measures like transit-oriented development and parking waivers would likely yield the greatest impact on affordability.
Why it matters
Understanding which zoning reforms can realistically expand housing supply helps policymakers address Colorado's growing affordability crisis.
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