Single-stair reform

Update building codes to permit mid-sized apartment buildings — typically up to six stories — with one stairway instead of two. Dual-stair rules force inefficient double-loaded corridors that limit light, waste space, and squeeze out family-sized homes.

Legalize housingUpdated May 2026

What it does: Permits single-stair apartment buildings up to ~6 stories
Works at: State · City
Cost to government: ~$0 — a building-code update
First major win: Culver City, 2025 (first in CA)
Momentum: Wins in LA, Denver & Virginia

Why it matters

The problem

Requiring two staircases in mid-rise buildings forces double-loaded-corridor layouts: long hallways, units on one side, limited natural light and ventilation, and wasted floor area. The rule blocks the 4–6 story 'missing middle' outright on smaller lots — and with it the larger two- and three-bedroom homes urban markets lack.

The fix

Permit single-stair buildings up to six stories under modern fire and safety standards. More homes per lot without added height, flexible floor plans that fit family-sized units, better light and cross-ventilation, and lower per-unit construction costs.

The misconception to defuse early: This applies to mid-rise buildings only, not skyscrapers — and single-stair buildings are standard in Europe, Japan, and Canada up to six stories, with excellent safety records. Modern fire protection makes the second stairway unnecessary at this scale.

Craft the policy

What separates versions that produce homes from versions that produce headlines.

Include

A clear height / number-of-stories limit
Explicitly cap single-stair buildings — typically at six stories — keeping them within fire-truck ladder reach and pre-empting the safety argument about compromised exits.
Example language: “The building has not more than six stories above grade plane.” — Seattle building code
Modernized fire and safety requirements
Base the reform on modern safety standards, and keep codes updating as technology allows equal-or-better protection than the old prescriptions.
Example language: “The minimum performance standards of the codes… shall not be diminished by county or city amendments.” — see Connecticut HB 05524 (2024)

Avoid

Affordability mandates
Inclusionary requirements make many mid-rise projects financially infeasible to construct.
Parking requirements
Mandatory parking adds $35,000–$38,000 per unit — roughly 8% of total project cost — passed straight to renters and buyers.
Redundant safety measurements
Stacking multiple duplicative fire-protection systems drives up construction costs without proportional safety gains.

After it passes — implementation checklist

1Set a clearly defined, near-future effective date
2Create a framework and timeline for updating the code as technology and safety standards evolve
3Identify the enforcement mechanism — appeals board, third-party standing, or Attorney General referral — when projects are wrongly denied
4Engage the key stakeholders early: firefighters' associations, fire marshals, and EMS

Make the case

“This reform applies only to mid-rise buildings, not skyscrapers.”

“Single-stair buildings are standard in Europe, Japan, and Canada up to six stories — with excellent safety records under modern fire protection.”

“Single-stair layouts enable larger, better-ventilated homes with more bedrooms — housing the families urban markets are losing.”

Likely allies — and why they show up

Single Stair TX: The reform's dedicated state coalition model
Center for Building in North America: The movement's research base
Strong Towns: Missing-middle housing is the point
Home builder associations: Small lots become buildable
Building & code official associations: Codes that reflect modern safety science
Building Design Institute of America: Better floor plans, better buildings

Wins & momentum

2025Culver City, CAFirst California municipality to legalize single-stair mid-rise construction — a YIMBY Los Angeles winYIMBY-backed
2025Los Angeles, CACity Council voted to draft an ordinance allowing single-stair buildings up to six storiesYIMBY-backed
2025Denver, COCouncil approved five-story single-stair buildings in the building & fire code — YIMBY DenverYIMBY-backed
2025Richmond, VARVA YIMBY backed Sen. VanValkenburg's statewide single-stair pushYIMBY-backed
2026VirginiaUpdated the state building code to allow single-stair up to four storiesYIMBY-backed

Research & resources

ResearchSingle-stair apartment buildings: the safety recordPew Charitable Trusts
ResearchFire protection in modern multifamily buildingsPew Charitable Trusts
DataSingle-stair reform trackerCenter for Building in North America
GuideStep Up for Single Stair — organizing guideStep Up campaign
VideoSingle-stair research data webinarYIMBY Action (YouTube)

Related playbooks

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Make it easy to turn empty offices into apartments people actually live in.

Bringing this to your city council?

You don't have to make the case alone. Our chapters have passed policies like this before — join one, or start one, and bring the movement with you.

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All solutions