The Parking Conversion
This pattern is shaped by
Problem
When parking was built for peak demand that occurs a few days per year, vast areas of urban land sit empty most hours of most days — and yet removing this parking feels like theft to the businesses and residents who depend on it. The land is needed; the parking is also needed; and so the lots persist, decade after decade, waiting for a conversion that never comes.
Evidence and Discussion
A surface parking lot in a North American city typically sits empty 60–70% of its operating hours. The Institute of Transportation Engineers' Parking Generation manual (5th edition, 2019) documents that most lots are sized for the 85th percentile demand hour — meaning they are overbuilt for all but the busiest moments. In Edmonton, a surface lot serving an office building fills during weekday business hours but empties by 6 PM; a lot serving a church fills Sunday morning and sits vacant the other 160 hours of the week. The land underneath — often in established neighborhoods with full infrastructure, mature trees, and transit access — contributes nothing to the city most of the time.
The economics have shifted. Buffalo, New York eliminated citywide parking minimums in 2017; Minneapolis followed in 2021; Edmonton reformed its zoning bylaw in 2020 to remove minimums in the downtown core and reduce them citywide. When cities stop mandating parking, developers stop building it unless tenants will pay. The result is a growing inventory of surface lots and parking structures that no longer pencil out — their land value exceeds their operating revenue. In Los Angeles, the Lincoln Property Company converted a 1960s-era parking structure at 600 Wilshire Boulevard into 125 residential units (completed 2021), demonstrating that even structured parking can become housing when land values justify the investment.
Parking structures present particular challenges. Their floor-to-floor heights (typically 3.0–3.3 meters) fall short of residential code minimums in many jurisdictions. Their floor plates lack natural light in the interior. Their ramps and sloped floors resist conversion. But adaptive reuse districts (203) can address these barriers directly: Edmonton's proposed adaptive reuse provisions allow reduced ceiling heights for conversions, accept light wells and interior courtyards as alternatives to window-per-room requirements, and waive parking minimums entirely for projects that remove parking. The building that was the problem becomes the solution.
The conversion sequence matters. A surface lot converts simply: demolish asphalt, remediate soil if contaminated, build. A parking structure requires more care. The structural capacity is usually adequate — parking loads exceed residential loads — but the mechanical, electrical, and plumbing systems must be added from scratch. The retrofit sequence (143) applies: seal the envelope first, then size mechanical systems for the improved building, not the open-air structure that existed before. Buildings converted from parking often achieve better envelope performance than new construction, because the heavy concrete structure provides thermal mass that moderates temperature swings.
Therefore
identify all surface parking lots and parking structures within a fifteen-minute walk of frequent transit. For each site, calculate the as-of-right residential capacity under current zoning. Where the housing value exceeds the parking revenue capitalized at current rates, flag the site for conversion priority. Within adaptive reuse districts, allow parking structure conversions by right, with floor-to-floor heights as low as 2.7 meters for residential use and no window requirements for bedrooms that open onto interior courtyards at least 6 meters wide. Require soil testing for surface lots; if contamination is found, remediation must precede construction. The conversion is successful when the new building houses more people than the parking lot held cars at its peak hour — a ratio of at least 1.5 residents per former parking space.