Everything You Need to Know About Building an ADU in the Twin Cities

What is an ADU?

An Accessory Dwelling Unit (ADU) is a secondary residential structure on a single-family lot. It can be a backyard cottage, above-garage apartment, in-law suite, or even a converted basement or attic. ADUs are fully independent living spaces, complete with kitchens, bathrooms, and private entrances.

Who are ADUs for?

ADUs are for grandparents, adult children, families, rental income… or just more space for your home office or studio.

Why are ADUs important?

A Second Suite/ADU allows city residents to expand without increasing the mass of the primary residence.

It can also allow for multi-generational living while maintaining independence and privacy from the primary home. Families can share resources, provide care-giving, and enjoy spending time together. ADUs are a cost-effective alternative to an apartment or even an assisted living facility.

Are ADUs legal in Minneapolis and St. Paul?

Yes. Both Minneapolis and St. Paul allow ADUs on most residential lots, subject to zoning, size, and setback requirements. Our team at SecondSuite is well-versed in Twin Cities ADU regulations and will guide you through the permitting process to ensure your project is 100% compliant.

What cities in the metro allow ADUs?

Minneapolis legalized ADUs on December 5th, 2014, when the Minneapolis City Council approved an amended zoning code to allow for “Accessory Dwelling Units.” In fact, Chris Strom, the founder and principal architect at Second Suite, has been an advisor to city zoning staff for recent Minneapolis residential code changes including the adoption of the Accessory Dwelling Unit Ordinance.

In St. Paul, the City Council voted October 17th, 2018 to allow Accessory Dwelling Units (ADUs) on single family lots throughout the city.

St. Louis Park also allows ADUs, as of November 13th, 2020, and Edina legalized ADUs in April 2024.

Other cities in Minnesota that allow ADUs include: Richfield, Roseville, Golden Valley, Wayzata, Bloomington, Columbia Heights, Burnsville, Eagan, White Bear Lake, New Brighton, Orono, Fridley, Crystal, Northfield, Long Lake, Duluth, and Rochester. Cities may have different regulations, but nation-wide trends in zoning are becoming more flexible in this regard.

How much does it cost to build an ADU in the Twin Cities?

Costs vary depending on the size, design, and type of ADU. Most ADU projects in Minneapolis and St. Paul range from $350,000 to $500,000. We provide transparent, itemized estimates and can work with you to find options that align with your budget.

How long does it take to design and build an ADU?

On average, the full process takes 8 to 12 months, including design, permitting, and construction. We manage everything in-house to streamline the timeline as much as possible.

What types of ADUs can you build?

We tailor each project to your property layout, goals, and city code. We specialize in a wide range of custom ADU types, including:

• Detached backyard cottages

• Garage conversions or above-garage apartments

• Basement or attic conversions

• Attached additions or in-law suites

What are the design options?

Accessory dwelling units (ADUs) are custom-designed for your location by Christopher Strom Architects. Homeowners may decide to “build-to-blend” with the character of their existing home, or take things in another direction and add a pleasing modern counterpoint to their yard. To find inspiration for your own ADU, view our completed projects, including Compact Living, Side Street Suite, Family Suite, and the GreenHouse. 

Can I rent out my ADU?

Yes. In both Minneapolis and St. Paul, ADUs can be rented as long-term housing units. Short-term rentals like Airbnb are restricted in some areas, so we’ll help you understand what’s allowed based on your location and use case.

Will an ADU increase my property value?

Yes. A thoughtfully designed ADU often increases resale value and can generate rental income or add space for multigenerational living—making your home more versatile and valuable.

Do I need a permit to build an ADU?

Yes. All ADUs in the Twin Cities require building permits and zoning approvals. We handle this process for you—from initial feasibility to final approval—so you don’t have to navigate it alone.

How do I know if my property is eligible for an ADU?

We offer a free ADU site assessment to determine if your lot qualifies. We’ll review your zoning, lot size, setbacks, and utility access, then provide recommendations based on local regulations and your goals.

Why work with SecondSuite?

SecondSuite is a local, design-build ADU specialist with deep experience in Minneapolis and St. Paul’s unique building codes. We handle everything—from architectural design and city approvals to construction and final inspections—with transparency, creativity, and care.

Still have questions?

We’re here to help. Contact us to schedule a consultation or request your free ADU feasibility review.