How Chicago Built Its Neighborhoods
Know the Buildings: How Chicago Built Its Neighborhoods
Written By: Harrison Cohen, Senior Vice President & Principal of Triton Realty Group
Almost every building Triton sells went up inside the same forty-year window. Between 1890 and 1930, Chicago’s population tripled, from about 1.1 million people to 3.4 million. The 1889 annexation alone added roughly 125 square miles and 225,000 residents in a single vote, bringing Lake View (Ravenswood included), Hyde Park, and Lake Township into the city.
All of those people needed a place to live near a streetcar line or an L stop, on an ordinary narrow city lot. Builders responded with a few designs they could repeat block after block: the two-flat, the three-flat, the six-flat, and the courtyard building. Brick walls, limestone trim, and the same floor plan repeated on each level. Simple, sturdy, and efficient.
A century later, those buildings still carry a large share of Chicago’s rental housing, and they make up most of what Triton sells. The next few pages cover each type: where it came from, how it was built, and why it still sells the way it does.
Building Type 01: The Two-Flat & Three-Flat
The idea is simple: one apartment per floor, and each floor is the same as the one below it. A two-flat has two apartments, and a three-flat has three. Chicagoans name them by unit count, not by architectural style. A two-flat with Tudor trim is still a two-flat.
Most were built between 1900 and 1920, often by small builders working on spec. The pitch to buyers was practical. Live in one unit, rent out the other, and let the rent help cover the mortgage. A 1915 plan book advertised its two-flat design as “a money-making proposition.” For generations of immigrant families, that’s exactly what it was: a first step into owning property.
Many early examples were greystones, with facades of Indiana limestone. Brick fronts became the norm because they were faster and cheaper to build, while limestone was reserved for trim: windowsills, belt courses, and parapet caps.
They are still everywhere. Two- to four-unit buildings make up about 27% of Chicago’s housing stock. In Brighton Park, New City, and South Lawndale, two-unit buildings alone account for more than two-thirds of all housing.
Building Type 02: The Six-Flat
Take a three-flat, add a mirror image of it next door, and put one shared entrance and staircase in the middle. That’s a six-flat: three floors, two apartments per floor, each one a mirror image of the unit across the landing.
Six-flats were built through the 1910s and 1920s alongside the two- and three-flats, using the same approach: face brick on the street side, cheaper common brick on the sides and back, and limestone for the trim. Classical Revival and Craftsman details are the most common, and some have stacked front porches. A less common version puts three apartments in front and three behind, with the rear units entered from the side.
Why do investors like them? Six units are enough to spread vacancy risk and operating costs across multiple rental incomes, yet small enough for a local owner to manage independently. The apartments are usually generous, with a front living room, bedrooms along a hallway, and the kitchen at the back, and the plans are easy to update.
It’s the building we sell more often than any other.
Building Type 03: The Courtyard Building
Courtyard buildings are the landmarks of many Chicago blocks. They are brick buildings shaped around a landscaped court, usually three stories over a raised basement, with separate entrances and stairs instead of one long interior hallway. Every apartment looks out on the street or the courtyard, and the courtyard works as a shared front yard for the building.
The form spread after the city’s 1902 Tenement House Ordinance. It required fireproof exterior walls on new apartment buildings and limited how much of a lot a building could cover, to 75% on a typical interior lot. A courtyard handled both rules well: as many units as the lot allowed, legal lot coverage, and a front lawn that helped rent the apartments. Construction stayed strong through the 1910s and 1920s, and the building type reached its peak popularity in 1929.
After that, the boom ended. The Great Depression halted most new construction in the 1930s. Later zoning rules introduced off-street parking requirements: one space for every three units in 1942 and one for every two units in 1957. These requirements made dense courtyard developments increasingly difficult to justify financially. For practical purposes, Chicago's historic courtyard building stock is unlikely to be replicated on a significant scale.
A Short History: From the Mecca Flats to Today
The courtyard idea reached Chicago before the boom. The earliest documented example is the Pelham Apartments, built in 1889 at 332 W. Dickens in Lincoln Park. Two years later came the best-known example: the Mecca at 3360 S. State Street. It was a 96-unit building designed by Willoughby J. Edbrooke and Franklin Pierce Burnham, completed in 1891 and first operated as a hotel for visitors to the 1893 World’s Columbian Exposition.
The Mecca lasted decades after the fair as an apartment building and became a cultural landmark of the South Side. It inspired Jimmy Blythe’s 1924 recording, “Mecca Flat Blues,” and Gwendolyn Brooks’s poem, “In the Mecca.” Illinois Institute of Technology demolished it in 1952 after a long fight with its tenants. Mies van der Rohe’s S.R. Crown Hall stands on the site today.
The building is gone, but its design lasted. The courtyard plan it helped popularize became one of the most common apartment buildings in the city, and courtyard buildings show up again and again in the deals we close.
Timeline
1889
City annexes approximately 125 sq. mi. and approximately 225,000 residents. Pelham Apartments, earliest documented courtyard building.
1891
The Mecca is completed at 3360 S. State St., 96 units.
1893
World's Columbian Exposition opens in Jackson Park.
1900–1920
Peak years for Chicago two-flats.
1902
Tenement House Ordinance: fireproof walls and lot-coverage limits.
1929
Courtyard buildings reach peak popularity; the Great Depression follows.
1942–1957
Off-street parking rules make dense courtyard plans hard to build.
1950
Chicago's population peaks at 3,620,962. It has declined since.
1952
The Mecca is demolished for the IIT campus.
1957
A new citywide zoning code built around floor-area ratios takes effect. It shapes Chicago development for more than 40 years.
1960s
The four-plus-one era: four floors of apartments over ground-level parking, mostly in Lakeview, Lincoln Park and along the North Side lakefront.
1962
Robert Taylor Homes is completed, the largest public housing development in the country.
1963
The Illinois Condominium Property Act makes condos legal.
1964
Marina City opens, 896 apartments in the world's tallest apartment towers at the time.
Late 1960s–Early 1970s
Neighborhood backlash and zoning changes end the four-plus-one.
1979
"Condomania" peaks. Downtown condo conversions hit a record that won't be approached again until the early 2000's.
1986
City Council passes the Chicago Residential Landlord and Tenant Ordinance (RLTO).
1997
Illinois bans local rent control with the Rent Control Preemption Act.
2000
The CHA launches its Plan for Transformation and begins demolishing its high-rises.
2004
Chicago adopts its first new zoning code in 47 years.
2005–2006
A second condo wave. Roughly 4,000 downtown rentals are slated for conversion in 2005, the most since 1979. In 2006 the wave moves to the suburbs, where more than 4,000 units convert.
2008
The foreclosure crisis hits small multifamily hardest. Two- to six-unit buildings account for 35% of Chicago foreclosure filings.
2013–2019
Chicago loses 11,775 units in two- to four-flat buildings.
2019
Chicago raises the owner vote needed to deconvert a condo building back to apartments from 75% to 85%.
2020
City Council approves a pilot allowing coach houses and basement and attic units in five areas of the city. Those units had been banned since 1957.
2021
First citywide reassessment under Assessor Fritz Kaegi. Chicago's total assessed value rises 31% since 2018, and non-residential property, which includes larger apartment buildings, rises 56%.
2022
The Connected Communities ordinance cuts parking requirements for new buildings near transit.
2025
City Council eliminates parking mandates near CTA train and bus lines, covering roughly three-quarters of the city. The kind of rule that ended the courtyard building is largely gone.
April 2026
Expanded rules for coach houses and basement and attic units take effect in 34 of Chicago's 50 wards.
September 2026
The National Park Service approves the Chicago Courtyard Apartment Buildings listing, opening the door for courtyard buildings across the city to join the National Register.
From History to the Closing Table: Why These Buildings Still Matter
These buildings were designed to do one job: house many people well on an ordinary city lot. A hundred years later, they still do that job better than most of what gets built today. That’s why they hold their value, and why buyers keep coming back to them.
The supply isn’t growing. Courtyard buildings and six-flats are expensive or impossible to replicate under today’s zoning and parking rules, and the smaller buildings are disappearing. According to DePaul University’s Institute for Housing Studies, Chicago lost 11,775 units in two- to four-flat buildings between 2013 and 2019, and nearly three-quarters of them were converted to single-family homes or taken out of housing altogether.
Selling one well takes more than a comp sheet. You have to know the block, the building type, its quirks (the garden unit, the boiler, the tenant mix), and the buyers looking for exactly that. That work is behind every sale we make.
Article written by Harrison A. Cohen, Senior Vice President, Principal, Triton Realty Group
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