Converting single-family homes to triplexes can ease the housing crisis and offer affordable, flexible options for more households. Why is it largely illegal?

A “Multigenerational Roommate House” outside of Dallas offers a model for affordable multifamily housing — if only it’s made legal in more places.
The home’s owner, Monte Anderson, “applied some savvy interpretation of local zoning rules to transform it into a legal, owner-occupied, multiunit home for five single adults ranging in age from almost twenty to over 70.” The units have separate entrances, bathrooms, and kitchenettes (full kitchens would trigger a zoning violation).
This style of housing is illegal under most U.S. zoning codes, explains Lauren Ronnander in an article for Strong Towns. But advocates for reform argue that allowing single-family conversions to duplexes or triplexes “can give residents the flexibility to live where they want at a price they can afford.”
According to Ronnander, allowing duplex conversions can also raise property values and, in turn, local tax revenue, benefiting cities. “In cities that make this type of housing legal by right, thousands of stagnant properties can be improved, raising property values, increasing tax revenue and revitalizing aging neighborhoods.” Legalizing single-family conversions can create more housing choices while avoiding the opposition and infrastructure costs that come with larger multifamily projects.
FULL STORY: This “Multigenerational Roommate House” Shows How To Heal the Housing Market

Florida Considers Legalizing ADUs
Current state law allows — but doesn’t require — cities to permit accessory dwelling units in single-family residential neighborhoods.

HUD Announces Plan to Build Housing on Public Lands
The agency will identify federally owned parcels appropriate for housing development and streamline the regulatory process to lease or transfer land to housing authorities and nonprofit developers.

Conservatives’ Decongestion Pricing Flip-Flop
When it comes to solving traffic problems, the current federal administration is on track for failure, waste, and hypocrisy.

Research Shows More Roads = More Driving
A national study shows, once again, that increasing road supply induces additional vehicle travel, particularly over the long run.

Can Progressive Planners Appeal to Conservative Principles?
Trump’s approach to policies like NYC’s congestion pricing isn’t just irrational and wasteful — it defies the tenets of conservatism. But there are ways to reframe the issues.

Oak Park Plans Earth Month Events
Join Oak Park, Illinois, for a series of Earth Month events highlighting the importance of community engagement and education, integrating sustainability into local plans, and planning for the most vulnerable, such as birds, bees and butterflies.
Urban Design for Planners 1: Software Tools
This six-course series explores essential urban design concepts using open source software and equips planners with the tools they need to participate fully in the urban design process.
Planning for Universal Design
Learn the tools for implementing Universal Design in planning regulations.
Florida Atlantic University
City of Grandview
Harvard GSD Executive Education
UCLA Lewis Center for Regional Policy Studies
City of Piedmont, CA
NYU Wagner Graduate School of Public Service
City of Cambridge, Maryland