Converting a Chicago Two-Flat Into a Single-Family Home: Zoning, Permits and Planning

01

Why Chicago Owners Convert Two-Flats

For many owners, a two-flat is the way into a neighborhood they love. Over time, the upper unit that once helped with the mortgage can matter less than the space it holds: room for children, a home office, a guest floor, or simply a house that works as a single home.

The pattern is well documented. DePaul University’s Institute for Housing Studies found in 2021 that Chicago lost more than 4,800 buildings of 2 to 4 units from 2013 to 2019, and that 47.5% of them were replaced by a single-family home, either by converting the existing building or through demolition and new construction. The activity was concentrated in higher-cost North and Northwest Side neighborhoods, led by North Center, Lakeview, West Town, Logan Square and Lincoln Park, and the researchers link it to demand from households that may want more space.

It is also a decision worth slowing down for. A second unit can carry rental income, house a parent or an adult child, or add flexibility at resale. The right answer depends on your plans for the next 10 years, and on what the City allows at your address.

02

Where Chicago Restricts Deconversion

Every conversion starts with zoning. The City’s Zoning and Land Use Map lets you look up your zoning district by address or property PIN, and the Department of Buildings notes that all projects require zoning approval. In 2 parts of the city, it can decide the whole project.

The 606 Predominance of the Block District

On January 27, 2021, City Council passed 2 anti-deconversion ordinances, for Pilsen and for the area around the 606 trail, to preserve buildings of 2 to 8 units. In September 2024, the Northwest Side Preservation Ordinance redrew the 606 district across parts of Avondale, Hermosa, Humboldt Park, Logan Square and West Town. In July 2025, City Council expanded the district’s boundary again.

Inside that district (Section 17-7-0590 of the Chicago Zoning Ordinance, as amended in 2024 and 2025), the rule works block by block:

• RS3 lots: a detached single-family house may not be established when more than 50% of the zoning lots on the same side of the street, between the 2 nearest intersecting streets, already hold buildings with more than 1 dwelling unit.
• RT3.5 lots: the same test applies at more than 40%.
• The exception: a detached house may still be allowed where a two-flat cannot be provided under the applicable bulk and density standards.

In practice, the same two-flat could be convertible on a given block and not on the next.

The Pilsen Multi-Unit Preservation District

In a mapped part of Pilsen (Section 17-7-0580), City Council passed a rule in January 2021 and corrected its text in April 2021. Under the corrected text, a detached house or two-flat may be established only when more than 50% of the zoning lots on the same side of the street, between the 2 nearest intersecting streets, already hold a detached house or a two-flat. It applies in RT4, RM4.5 through RM6.5, B and C districts inside the mapped boundary.

If the Plan Turns Into a Teardown

The same 2 pilot areas carry a demolition permit surcharge. Since the 2024 ordinance, it is $60,000 for demolishing a detached house, townhouse or two-flat, and the Department of Housing lists it as running through December 31, 2029. Rules like these change, so confirm the current version for your address with the City and your design team.

03

The Chicago Building Permit Path

Why It Is Not an Express Permit

Chicago’s Express Permit Program covers repairs and small, defined projects. The Department of Buildings lists reducing the number of legal units, such as changing a legal two-flat to a single-family home, as not eligible for its express deconversion permit, which exists to remove unit features that were installed without a permit. Express interior permits also exclude structural work and new or rearranged interior stairs.

Licensed Drawings and Standard Plan Review

For any project that needs a plan-based permit, the City requires an Illinois-licensed architect or engineer to prepare the construction documents, and that professional determines the zoning and code requirements that apply to your property.

The Department of Buildings offers 4 review programs for plan-based permits. Standard Plan Review is its main process for work that needs architectural plans, including residential projects with fewer than 50 dwelling units. Applications go through E-Plan, the City’s online permit system, and the department assigns its own project manager as the applicant’s single point of contact during review. The description of work states how many dwelling units the building has and how many the work affects, so the unit count is part of the record from the start.

For a fuller walk-through of review types, see our guide to Chicago remodeling permits.

Landmark Districts

If your building sits in a Chicago Landmark District, the Commission on Chicago Landmarks reviews the building permit as part of the normal process; no additional City permit is required. In districts, the protected features are typically the exterior elevations visible from the public way, and the Commission says it reviews more than 900 landmark permits a year, most approved in 1 day. Our article on historic home renovations in Chicago covers the design side of older buildings.

04

Design Moves That Make a Two-Flat Feel Like a Single Home

A good conversion does not read as 2 apartments with a door between them. It reads as a house, and 3 decisions shape that.

A Single Kitchen, Placed for How You Live

The conversion leaves you choosing which kitchen becomes the kitchen. The main floor often makes sense for its connection to the yard, the street and the dining room. The upper kitchen does not have to disappear without a trace: depending on the building, its location may suit a laundry room, a primary bath or a coffee station near the bedrooms. Your designer and licensed trades confirm what the existing lines can support.

The Stair Decides the Floor Plan

Depending on the building, the upper unit may be reached through a shared front hall, a rear stair, or both. An interior stair that connects the living spaces is what turns 2 floors into a single house, and where it lands shapes every room around it. Because the city’s express interior permit excludes new and rearranged interior stairs, the stair belongs in the licensed drawings and the plan-based permit from the start.

A Primary Suite Upstairs

With the upper floor no longer a separate apartment, it can become the private floor of the house: a primary suite with a real closet and bath, plus bedrooms for children or guests. The former upper living room can become the suite itself or a quiet family room.

The same questions sit behind any single-family home remodeling in Chicago project; a two-flat simply asks them in a more interesting order.

05

Consolidating Utilities and Meters

ComEd’s service rules treat individual residential units as separate customers that require separate metering, so a legal two-flat normally carries an electric meter for each unit, and the conversion changes that. If each unit also has its own heating equipment and water heater, each of those becomes a decision too.

• Electric: ComEd’s Modification & Relocation Service Application covers changes to existing service, asks you to work with a licensed electrical professional, and assigns a ComEd Project Lead to the job. Its meter checklist does not allow empty meter fittings: a meter housing that will no longer be used has its connection hardware removed and is covered with a blank metal face plate.
• Gas: Peoples Gas publishes a rehab process for removing and relocating meters and says it contacts you within 3 business days of a request. Its guidance names the ideal meter location as the front of the house or 4 feet back on the side, 3 to 4 feet from any electric source.
• Heating, cooling and hot water: you can keep existing systems as zones of a single house or replace them with equipment sized for the whole home. Your mechanical contractor sizes it to the finished plan, not the old unit lines.

Utility work runs on the utilities’ own schedules, not the City’s, so start those applications once the design is settled rather than after construction begins.

06

What Drives the Budget

We do not publish a typical price for a deconversion, because the cost turns on decisions only your building can answer. These are the drivers to understand before you set a number:

• The stair and the structure: new floor openings, framing and the engineering behind them.
• How much you consolidate: keeping both mechanical systems as zones costs differently than replacing them.
• The kitchen and the primary suite: removing a kitchen is the easy part; the new kitchen and baths are where finish choices show up.
• Utility work: meter removals, service changes and any relocation.
• The age of the building: what sits behind the plaster in an older two-flat can stay unknown until walls open.
• Zoning and review: a district check or a landmark review can add steps before construction starts.

For a framework you can use with any estimate, see our guide to budgeting for a Chicago home remodel.

07

How Design-Build Runs the Conversion

A two-flat conversion touches zoning, structure, 2 sets of systems and 2 utilities at once, which is why it rewards a single team that holds the whole sequence. Areté has worked as a Chicago design-build remodeling firm since 2002, with design and construction under one roof and an in-house interior design team. With design-build remodeling in Chicago, the same team carries the project from design through construction, and a Project Manager runs it from start to finish.

A sensible sequence for a two-flat looks like this:

1. Confirm zoning at the address, including the 606 and Pilsen districts.
2. Walk the building and set the plan: the kitchen, the stair and the primary suite.
3. Prepare the licensed drawings and file the plan-based permit.
4. Start the ComEd and Peoples Gas applications once the design is settled.
5. Build, pass the City inspections and move into a single home.

If the conversion is part of a larger renovation, our 2026 guide to whole-house remodeling in Chicago covers planning and living through the work. To see the wider range of what we do for houses, visit our single-family home remodeling services in Chicago.

08

Frequently Asked Questions