CALL FOR ENTRIES: Denver’s Single Stair Housing Challenge
The competition includes a $20k prize pool & invites thoughtful proposals for mid-rise point access blocks on underutilized lots where building code reform can unlock valuable housing potential
Cedarhusen is Stockholm's first mass timber high rise and contains 245 units which are primarily dual aspect. At 13 stories tall, the building would be illegal to build anywhere in the US due to the use of single stair egress.
For nearly 5 decades, Seattle has constructed unique single-stair midrise condominiums that increase urban home ownership & help address the housing crisis.
This is a condo🧵of rare Seattle point access blocks that are illegal anywhere else in the US (except NYC + Honolulu).
Seattle's Parkview Green is an innovative housing model. Property owners who have lived in a home on the site for 25 years will not be displaced by development of the small lot.
Instead, the owners will live on a top floor unit of the 16-unit, 4-story, single-stair project.
44 West 77th Street, NYC (1907):
•15 stories
•34 units
•82'x100' lot
•full depth units
•1 stair
The project is illegal to build in US today due to the use of a single stair
Two Ten Comstock is among the rarest housing projects in the US. Featuring 8 family size urban condominiums w/ a single stair to reach the upper floors, the project would be illegal to build in any other city in the US due to Seattle's unique building code. Good find
@buildllc
Capitol Hill single stair🧵
Point access blocks are so prevalent in Seattle's Capitol Hill that the neighborhood has added hundreds of units on small lots using the city's unique single stair code provision.
These projects are illegal to build in most of the US.
Dubbed the "world's littlest skyscraper," the Newby–McMahon Building in Wichita Falls, TX:
•4 stories
•40' tall
•10'x16' footprint
Originally constructed in 1919, if built today, the building would be illegal to build in most of the US due to the use of a single stair
Adding 19 units on a 40' wide lot in Seattle's Wallingford neighborhood, the Densmore apartments create new mid-rise housing options with a 5-story, single stair design.
The project is illegal to build in almost the entire US due to code constraints on single-stair apartments.
Seattle's building code promotes more walkable, low-carbon communities by allowing for small-lot, mixed-use development
Made possible by the city's unique single-stair code, this is a🧵of unique mixed-use projects that activate their neighborhoods & are illegal in most of the US
Seattle's University District is walkable and bikeable, and is served by transit.
This is a 🧵 of student housing options created in the U District using the city's unique single-stair building code
Single stair apartments can provide a safer option for new housing in the US
Instead of long dead-end corridors allowed in 2-stair double-loaded corridors, point access blocks fire safety measures include:
•pressurized stairs
•limits on height & unit count
•short corridors
How effective are single-stair midrises at increasing density?
By placing 7 of Seattle's single-stair precedents on underutilized lots, this 2-block study adds 100 infill housing units. 7 precedents that are illegal in most of the US & provide a range of housing options
Seattle's building code has safely used 6-story single stair egress for nearly 50 years.
The Grenfell disaster is frequently used to discount Seattle's unique code but there are major fundamental differences in the comparison between Grenfell and what is permitted in Seattle.
Winner of Finland's NBO Housing Competition for affordable housing model, the HASO & HEKA Eskolantie Apartments in Helsinki, Finland by Matti Iiramo:
•7 wood-framed stories
•4 point access blocks
The project is illegal in the US due to the height of the single-stair buildings
Legalize this building in every city and on every Main St in the US.
Located in West Seattle, the Admiral Mixed-Use is a 4-story point access block containing 12 condos & ground floor retail.
Due to building IBC restrictions, the project is illegal to build in most of the US
Broadway Hill Apartments are aspirational infill
•Compact 30' wide lot
•4-story walkup
•9-units
•Exterior central stair w/ outdoor gardens at each floor
The gorgeous project in Seattle's Capitol Hill is illegal in almost the entire US due to the single stair plan
This is a 🧵of dense Seattle projects on small lots 35' wide or skinnier that are illegal to build in the US outside NYC and Honolulu
Seattle's unique code encourages small infill by allowing the use of a single stair up to 6 stories in height
One of my favorite accounts to watch this year has been
@aussieflya
sharing construction progress of a point access block:
•30' wide lot
•6 floors + mezzanine
•17 units
•studio, 1, 2, & 3-bed unit mix
•1 stair
The project is the largest possible using a single stair in NYC
To encourage smart growth, the US needs to add density to neighborhoods originally zoned for only single family homes.
To do this, the building code must be reformed to encourage more single-stair projects like Seattle's compact 10-unit Jansen Court.
Preserving an existing century-old home, Seattle's Jansen Court apartments use the city's unique building code to add density to a small urban site by only using a single stair.
Because it is a 5-story point access block, it would be illegal to build anywhere else in the US.
Thanks to Seattle's unique stair code, point access blocks like the Alki Condominiums create density on small beachfront lots
Located on Alki Beach, the project adds 10 units to the waterfront
At 6-stories tall, the Alki Condominiums are illegal to build in most US cities
Ironic that Seattle's East Union Lofts won numerous state and
@AIANational
awards while being featured in dozens of publications that fail to mention one key fact:
In the US, the single-stair project was only legal to build in Seattle and NYC at the time of construction
Built in 1981, before Seattle capped single-stair projects a 6 stories, the Bellevue Ave Condos have:
•19 units (some that are multiple levels)
•2 and 3-bed units
•26,000 GSF
•8 stories
•1 stair
Today, the point access block would be illegal to build anywhere in the US
Zoning often restricts infill development to low-rise, 3 or 4-story construction.
These low rise single-stair Seattle projects add density to small sites & are illegal to build in most of the US. Building code needs to be updated to allow this type of fine-grained infill.🧵
Left: non-IBC compliant 4-story single-stair apartments built in Seattle
Right: IBC compliant 3-story single-stair apartment with multiple mezzanines in DC
Seattle's 13th Ave Apartments efficiently use a single-stair to add (20) 1-bed units on a small urban lot in Capitol Hill.
Due to building code restrictions, the 5-story point access block is illegal to build in most the US and is only allowed in Seattle, NYC, & Honolulu.
One of Seattle's most ambitious single-stair designs is located in Phinney Ridge:
•6-stories
•24 units
•Narrow 35' wide lot
•pursuing Living Building Pedal Certification
The midrise project is illegal to build in most US cities due to the use of a single stair
The 8-story Hirbour Tower in Butte, MT was America's first skyscraper west of the Mississippi
Renovated to include housing using a code variance, the single-stair project adds 7 units on a 28' wide lot while preserving a historic structure
How to promote a walkable neighborhood with a small lot:
•1,600sf ground floor commercial space
•4 floors with 16 units above
•1 stair
At 5-stories tall, this mixed-use infill in Seattle's Queen Anne is illegal to build in most of the US due to the use of a single stair
In Seattle's U District, the 8th Ave Apartments propose to add 18 units to a 50'X60' lot using a compact, efficient single-stair design.
The 60' tall, 5-story walkup project is illegal to building in nearly all of the US due to the use of a single-stair
Designed by awarding-winning firm Weinstein A+U, the Alki Condos replaced two single-family homes with (10) 1,800+ sf units.
The 6-story, waterfront project overlooks Seattle's skyline & is made possible by the city's unique single-stair building code
Gramercy North with full-floor condominiums & located in Downtown Manhattan:
•Built in 2019
•26' wide lot
•14 condos
•1,500 SF, 2-bd units
•15 stories
•1 scissor stair
Due to the use of a scissor stair, the project would be illegal to build in any other city in the US
Seattle's NW 39th St Apartments will replace 2 single family homes in Ballard w/ 22 units & a the unit mix includes (10) 2-bed units
All units are triple-aspect providing abundant daylight
Workshop ipb's infill project uses single stair egress to create small lot density
Designed, developed, and built by
@buildllc
, the 4-story, single-stair Park Modern project is one of the most innovative mixed-use projects in the US
Providing 12 condos atop three ground-floor commercial spaces, the project is also illegal to build in most of the US
Excited to share that next week, I'll be presenting to Minnesota's APA Chapter to discuss point access blocks.
Reforming US building code to allow taller point access blocks will enable the construction of healthier, more varied, and more sustainable multi-family housing.
Zurich's Rocket&Tigerli project will soon be the world's tallest mass timber building.
At 32 floors and over 250 units, the building would be illegal to build anywhere in the US due to the use of single stair egress.
The Louisiana Apartments (1908) at 507 West 113th Street in NYC was built on a 50'x85' lot. The project contains:
•7 floors
•21 units originally (now 33)
•2, 3, & 5 bed, cross-ventilating unit plans
•1 elevator
•1 stair
Seattle's 301 Belmont is illegal to build according every building code in the US
Thanks to innovative architects working w/ forward-looking building officials, the mid-rise project has a construction permit to add 34 units on a small corner lot using single stair egress
We can build better cities in the US that are more walkable, family-friendly, and affordable.
We need to update the code to allow single-stair projects like Seattle's Capitol View, built by Habitat for Humanity
Seattle's single-stair provisions are one of the most unique approaches to housing in the US.
Proven safe through decades of use, this 🧵details fascinating insights on Seattle single-stair safety shared by a fire safety expert last week when we presented to an AIA chapter.
Which apartment floor plan is safer?
The double-loaded corridor on the left with long travel distances, a dead-end corridor, and dozens of residents on each floor
OR
the 4-story, point access block on the right with a compact footprint, short corridor, and pressurized stair?
A narrow midblock midrise, Seattle's Bellevue Ave apartments are designed to add 45 units on a narrow 40' wide lot w/ two single-stair structures.
The six-story paired point access blocks would be illegal in most US cities due to the use of single-stair egress.
Seattle's 403 Thirteenth boutique condominiums add 6 units on small 50'x60' corner lot in Capitol Hill. Units range in size from 500 SF studios up to 1,200 SF 2-beds.
The 40' tall infill project is illegal in nearly all of the US due to the use of a single stair.
The state of Vermont allows taller single-stair housing than any state in the US because the state adopts NFPA 101 for egress requirements & not the IBC.
NFPA 101 (30.4.2.6) allows 4-story single-stair w/ 4 units per floor and VT is exploring amending to allow 6 units per floor.
Stockholm developers plan to continue the use of mass timber for large scale high-rise projects with the construction of Stockholm Wood City beginning in 2025
By late 2026, the Flatiron Building will be residential, with 60 luxury condos replacing the offices where Macmillan editors once pored over copy.
Read more:
Designed by Citizen Design, Seattle's Whittier Heights apartments will replace a single-family residence with:
•4 stories + basement
•20 one-bed and studio units
•9,300 gsf
Located on a small 66'x90' lot, the single stair design is illegal in most US cities
In Seattle's Capitol Hill, the Broadway East Condos add 8 units to a small lot on the same block as single-family homes and large apartment blocks.
The 4-story, single-stair project with 1 and 2-bed units is illegal to build in most of the US due to the lack of a second stair.
Located on a small urban lot, Seattle's Solo Lofts are a 20-unit, six-story condo project that includes 1-bed units and 2-bed penthouses.
The efficient condo project is made possible by Seattle's unique stair code & it would be illegal to build in most US cities.
The Willet is a simple, modern 4-story apartment near the University of Washington in Seattle. Neighbors & residents probably have no idea that the small project would be illegal to build in virtually every other American city due to the 4-story height and use of a single stair
We can build housing in the US that encourages families to stay in our cities and creates active and thriving neighborhoods.
We need to update the code to legalize single-stair projects like SOLA 16 that fits (8) 2-bed units on a small 40' wide lot.
The Casa 40 Condo Building in Cordoba, Argentina:
•5 stories
•9m wide lot
•18 units
•A central, social stair that is the focal point of the project
•All units ventilate from central courtyard
Legalize this type of straightforward single-stair housing in the US
A recent study investigated how building typology affects total energy performance & daylight in buildings w/ similar urban densities
The results:
The point access typology is the best plan type, providing optimal daylight & energy performance
Point access blocks, like Seattle's new Capitol View condos, create affordable home ownership opportunities small urban lot thanks to the city's one-of-a-kind building code and
@habitatskc
. Recently completed, the project features 13 units on a small sloped site.
Paris' Opening Ceremony was incredible but did anyone else notice the open and daylit point access block that kicked off the Olympic ménage à trois scene?
Cities across the US lack missing middle housing. Not due to a lack of demand but because it isn't allowed in the building code.
Seattle's unique code promotes development of mid-rises, like 602 Flats, on small urban lots, by allowing point access blocks taller than 3 stories
Located on a 35' wide lot, the 4-story Son Mixed-Use project will add (12) 1-bed units and 1,500 SF of ground floor commercial space to Seattle's Wallingford neighborhood.
The project is illegal to building in 99.9% of the US due to the use of a single stair
Seattle's Fremont Flats mid-rise is 5-stories & 2 buildings on a narrow urban infill site in the Fremont.
Featuring 14-units ranging in size from SEDU’s to 1 and 2-bed apartments, the project is illegal to build in almost every city in the US due to the use of a single-stair
Brooklyn's 34 Belvedere Apartments use a single-stair design to add 8 units and rooftop garden to a small lot along a vibrant street.
Outside Seattle, Honolulu, & NYC, 4-story point access block apartments are illegal to build in the rest of the US
@DFthoughtz
@AlexDRMather
In the US, our building codes limit the use of single stair egress to 3 stories max for apartments. In general, the rest of the world allows single stair egress at much greater heights and at lower for death rates than the US
b9 Architects established a niche designing missing middle housing across Seattle using the city's unique single-stair provisions.
Here's a look at a collection of b9's single-stair projects that are illegal in most of the US outside of Seattle🧵
We can to encourage more fine-grained urbanism in the US that adds better housing and active uses.
We need to follow Seattle's lead and update the code to allow projects like the Union Lofts
In most US cities, a narrow L-shaped lot would not be developed with any density, if at all.
That is not the case in Seattle where the city's unique stair code has allowed a narrow L-shaped lot to be developed into the Fitzgerald, a recently completed 13-units of luxury condos
Located in Seattle's Wallingford neighborhood, the 44th St Apartments will replace a single family home and include a mix of 1, 2, and 3 bed units.
The efficient design creates housing abundance through use of Seattle's unique stair code
good find
@pushtheneedle
Virginia becomes the first East Coast state to pass a single-stair reform bill and joins Washington, Oregon, and California which all passed similar bills in 2023.
Which state will move to improve housing options next?
Today, the Governor signed my bill, HB368, into law, which begins the process to allow a single stairway exit for smaller residential buildings instead of requiring multiple stairway exits.
Seattle's West Highland Drive Condos include expansive views of downtown and Elliott Bay:
•Completed in 1995
•8 floors
•5 units
•Direct unit elevator access
•Below grade parking
•1 stair
The single-stair project is illegal to build in most US cities
Heading to
@YIMBYtown
with a copy of the Sunday
@denverpost
featuring a front page story on Colorado's single-stair movement by
@SethKlamann
Excited to see building code reform being elevated into the housing crisis conversation
Seattle's Hemingway Condominiums creates density on a small, sloped urban site. The point access block adds 7 family-sized units to a site formerly occupied by a single family home.
The 4-story project would be illegal in most of the US due to the height & use of a single-stair.
Stokhusgade is a slender multi-family housing project designed by Holscher Nordberg in the center of Copenhagen:
•20' wide site
•7 stories
•5 units
•1 stair
Built in 2008, the dense infill project is illegal to build in the US due to the use of a single stair
A great example of missing middle housing that can not exist in most US cities, Sola16 adds 8 family sized 2-bed units to Seattle's Eastlake neighborhood on a small urban lot.
The city's anomalous code promotes infill options like Sola16 by allowing 6-story single-stair apts
Seattle's Galloway Apartments small lot infill:
🤏35' wide/3,200 SF lot
🤏4 story/40' height
👎7' side setbacks
👏(8) 1-bed units
🚌1 block to rapid transit
🌲4-star Built Green
☝️1 stair
🙅Illegal in most of the US due to the lack of a second stair
Completed in 2022, Seattle's 15th Ave Apartments feature (8) family-sized 3 and 4-bed units on a 40' wide lot in the walkable, transit rich U District
The 4-story project is illegal to build in most of the US because it only uses a single exterior stair for egress
single stair boss level:
Pasteurs Tårn, Copenhagen
A narrow, tall tower recently completed in the Carlsberg area
•37 stories (~6 units/floor)
•172 units - ranging in size from studios to 5-beds
•120m height
Designed as a collaboration between Wingårdhs and Vilhelm Lauritzen
Seattle's Midvale apartments add 20 units to a small lot formerly occupied by a single family home. The 4-story walkup features an entry stoop harkening back to a Brooklyn Brownstone.
Using a single-stair, Midvale is illegal to build in most of the US.
E Denny Way is an 18 unit condo proposed for Seattle's Capitol Hill
Preserving the existing neighborhood character, the 4-story project is on the same block as single-family homes and 3 & 4-story apts
The project is illegal to build in most US cities due to single-stair egress
Wadsworth Court, NYC (1909). A pre-war urban housing gem:
•Six stories
•29 units (66 bedrooms)
•75'x100' lot
•Interior courtyard
•1 stair
The project is illegal to build in US today due to the use of a single stair
Built in 2014 in Seattle's Greenwood neighborhood, Studio 85th replaced a single family home with a 4-story mixed-use building that includes ground floor retail and 7 apartment units.
Due to the use of a single stair & height, the project is illegal in most of the US
Excited to receive an Emergent Ventures grant to organize a point access block design competition and re-envision the future of American urbanism. Details coming soon.
Big thanks to
@tylercowen
& the EV/
@mercatus
team for supporting single-stair reform!
Seattle's Magedai Apartments propose adding 16 units of housing to the Ballard neighborhood on a 50' wide lot.
The five-story project featuring a ground floor restaurant is illegal in most US cities due to the use of single-stair egress.
Seattle's Alki peninsula has the highest concentration of the city's unique single stair housing
Small lots along the waterfront zoned for height are well suited for development into high-quality point access block condos and date back to 1980's -->🧵
Seattle's sleek Greenwood Avenue apartments is a missing middle gem:
•27' wide urban lot
•side setbacks
•(8) 1-bed apartments replacing a single-family home
Maximizing housing density by utilizing Seattle's unique stair code, it would be illegal to build in most of the US
Freeport Tower, Copenhagen by Praksis - The project converted an abandoned grain silo to high-quality, cross ventilating residences:
-12 stories
-44 units
-2 point access blocks
Also illegal to build in the US due to the height of the single stair.
"The Silo" is an adaptive reuse project in Copenhagen by Cobe. The project turned an abandoned grain silo into housing with:
-17 stories
-39 units
-750sf-3,200sf unit sizes
-2 point access blocks
Due to the height, the single stair project would be illegal to build in the US
The Aerie at Green Lake is an eclectic multifamily project that seeks to add 18 units to a small 45'x100' lot in one of Seattle's recently upzoned Urban Villages.
The 5-story midrise apartment would be illegal in most US cities due to the use of a single stair.
•US cities where 6 story point access blocks are permitted
•States that debated legalizing single stair egress in 2023 (w/ bills passed in CA, OR, & WA)
•States working on local and statewide single-stair initiatives
Who am I missing?
Denver's Krisana Park is a neighborhood full of Eichler-inspired modern homes from the 1950's
If Colorado passes HB24-1239, Denver could be infused with fresh single-stair, mid-rise architecture adding density on small lots
@lewi3_lewis
the code is tailored to create a safe exit condition for a mid-rise single-stair apt. The stair is in a rated enclosure w/ rated doors at each floor and is pressurized to push smoke out and keep the exiting condition safe along with multiple other measures
In the US, the requirement for multiple egress stairs is a holdover from an era when common fire safety strategies like fire rated construction & sprinklers did not exist
A modern approach utilizing layers of safety strategies creates a safe, easily accessible exit condition
To address the housing crisis, the City of Denver is including single-stair access code reform in their application for PRO Housing Grant from HUD.
Updates to the city's building code have a significant potential for improving housing options.
Seattle's 318 Lofts Passive House Apartments are designed to prioritize long-term sustainability and affordability. The 6-story project efficiently adds 20 units to a narrow 40' wide lot through the use of a single-stair.
The compact design is illegal to build in most US cities
The US needs to build housing that preserves & prioritizes open space.
To do this, the building code needs reform to allow compact, point access blocks like Seattle's Greenfire - part of a campus where >50% of the site is dedicated to urban wildlife habitat & gardens
Last week, Tennessee became the latest state to pass single stair legislation.
On 4/29, Governor Lee signed HB 2925 - SB 2834 and established a path for taller single-stair housing and improved housing options in the state.
What is the potential for unlocking small lot infill by allowing taller point access blocks?
Within Denver, legalizing 6-story single-stair housing would unlock denser development on > 14,000 small lots where zoning allows heights of 3-6 stories with narrow 25ft – 50ft widths
Seattle's building code not only allows taller single-stair housing than most of the US but code amendments also allow taller wood-framed buildings
This aspect of Seattle's building code has promoted additional housing density & can be a model for the US
This is an Affordable housing project in Denver that is a series of connected point access blocks w/ its height restricted by the building code's restriction on single-stair apt height
On a lot zoned for 6-stories, the unit quantity could increase by 33% by adding a 4th floor.