Conversion to three-unit dwelling

We explain the City's requirements to convert to a three-unit dwelling or to two dwellings plus an accessory dwelling unit (ADU).


In Minneapolis, you can convert a single-family home or duplex to a three-unit dwelling. This type of conversion is a major project under the Minnesota Building Code.

Examples of a three-unit dwelling:

  • Three-plex
  • Duplex with an accessory dwelling unit (ADU)

Converting a single-family home or duplex to a structure with 3 or more dwelling units is a significant undertaking under the Minnesota Building Code. The applicable building code section changes from 1309, Minnesota Residential Code (IRC) to 1305, Minnesota Building Code (IBC). This change in applicable code sections constitutes a special condition. Because of this, Construction Documents prepared by a MN licensed architect are required for all projects converting an single family dwelling or duplex to a 3 or more unit apartment building.


Property owners who want to convert a single-family dwelling or duplex to a three-unit dwelling must:

  1. Learn relevant State and City rules
  2. Create a floor plan
  3. Complete a building permit application
  4. Get zoning and plan review approval

Download printable version of conversion to three-unit dwelling

Step 1: Learn relevant State and City rules

When you convert a single-family home or duplex to a three-unit dwelling, the building use changes:

  • From the International Residential Code (IRC) requirements
  • To R2 Occupancy (apartment) rules under the International Building Code (IBC) / Minnesota Conservation Code for Existing Buildings, Chapter 10

If your converted dwelling will include a detached ADU, you will need to know the requirements for a detached ADU.

Read Detached accessory dwelling unit (ADU) requirements

Step 2: Create a floor plan

Create a floor plan for your project drawn to scale. (You will submit the floor plan in digital (PDF) format shortly after you apply for the permit.)

Your floor plan must:

  • Show the layout of the dwelling along with any proposed changes
  • Include each level of the home, such as the:
    • Basement
    • Main floor
    • Second floor
    • Attic
  • Show all the following:
    • An outline of the foundation walls
    • An outline of the interior and exterior walls
    • The location of windows, doors and stairways
  • Identify the rooms by name, such as:
    • Living room
    • Dining room
    • Kitchen (include arrangement of cabinets, stoves, sink, refrigerator)
    • Bedroom
    • Laundry
    • Mechanical
    • Storage
  • List room dimensions (you can use a simple description, such as 12 X 10 feet)

Your floor plans must also show any planned construction work, such as the location where:

  • New walls will be built
  • Old walls will be removed
  • You will make changes to doors, windows or floor openings
  • Kitchens will be added

Step 3: Complete a building permit application

After you have finished your floor plan, the next step is to complete a building permit application.

Download and complete a building permit application

Submit your completed building permit application by email

After you submit the building permit:

  • You will receive an email from a City development coordinator.
  • The development coordinator will explain the process to submit your floor plans using the City’s ProjectDox electronic plan system. (Note: Due to COVID-19, you must submit plans online. We may accept paper plans in the future.)
  • After you submit the floor plans, City staff will do a zoning and plan review.

See the City’s ProjectDox electronic plan system

Step 4: Get zoning and plan review approval

When a property owner wants to change the use of a building, the City must do a zoning and plan review to approve the floor plan.

Staff people from two divisions in the City’s Community Planning & Economic Development (CPED) department will review your plan:

  • CPED Zoning will verify that converting from a single-family dwelling to a duplex complies with the City Zoning Ordinance.
  • CPED Construction Code Services will review for state building code requirements.

During the review, CPED might send you comments for correction. If this happens, you will need to correct the floor plan and resubmit it.

Once CPED approves your plans

  • We will issue a building permit to officially convert the building to a duplex.
  • You will be notified by our electronic system to pay for the permit.

After you finish the building project

After you finish the project, the City will inspect the new dwelling. Once CPED approves your work, we will:

  • Update the certificate of occupancy to a three-unit dwelling.
  • Change the unit count record to 3 in department permit records.
  • Notify the City’s Solid Waste & Recycling and Utility Billing (water department) that the conversion is complete. City services will then be billed for a three-unit dwelling.

Other project types

Request accessible format

If you need help with this information, please email 311, or call 311 or 612-673-3000.

Please tell us what format you need. It will help us if you say what assistive technology you use.

Contact us

Minneapolis Development Review

Community Planning & Economic Development


Public Service Building
505 Fourth Ave. S., Room 220
Minneapolis, MN 55415

Service Center hours
Monday - Thursday
8:00 a.m. - 4:00 p.m.
9:00 a.m. - 4:00 p.m. 

Building Permit Application

Community Planning & Economic Development