Published August 28, 2026
An in-law suite in the Twin Cities costs $80,000 to $220,000 depending on whether you convert existing space or build new. Before you price anything, answer the zoning question: does your city allow a second dwelling unit on your lot, and does it require the owner to live on site?
Three ways to build one
| Approach | Cost | Timeline |
|---|---|---|
| Convert existing main-floor space | $60,000–$120,000 | 8–12 weeks |
| Finish a walkout basement as a suite | $80,000–$160,000 | 10–16 weeks |
| Garage conversion with a bath and kitchenette | $70,000–$140,000 | 10–14 weeks |
| New attached addition | $150,000–$300,000 | 4–7 months |
| Detached ADU | $180,000–$350,000 | 5–9 months |
Zoning: the part people skip
Minneapolis and Saint Paul both permit accessory dwelling units in most residential districts. Most suburbs are more restrictive — some prohibit second units entirely, some allow them only for family members, and some require an additional off-street parking space. Call the zoning office, not the building department, and ask whether a second dwelling unit is permitted in your district and whether there is an owner-occupancy requirement.
If a second full kitchen is not allowed, a suite with a wet bar, refrigerator, microwave, and sink is almost always fine. That distinction — range or no range — is often what separates "bedroom suite" from "dwelling unit" in a city's code.
Accessibility details worth paying for
If the suite is for aging parents, build for the next fifteen years, not this year:
- 36 inch doors throughout, including the bathroom — costs almost nothing at framing and is expensive later
- Zero-threshold curbless shower with a linear drain: $2,000–$5,000 over a standard tub-shower
- Blocking in bathroom walls for future grab bars: $200 during framing
- Lever handles on all doors and faucets
- Rocker switches at 42 inches, outlets at 18 inches
- A no-step entry on at least one door — a gentle grade or a ramp integrated into the landscaping
- Wider hallway at 42 inches where the layout allows
Minnesota-specific build items
A suite needs its own heat source or a zoned extension of the existing system. A single-zone ductless mini-split runs $4,000 to $8,000 installed and is often the cleanest answer for an addition or garage conversion in our climate. Garage conversions also need the slab insulated — an uninsulated garage floor is unbearable in January and requires either a raised insulated subfloor or foam under a new slab.
Every bedroom needs egress, and every unit needs interconnected smoke and CO alarms. If it is a legal second unit, add fire separation between units.
Value
Multigenerational housing demand in the metro is real and rising. A well-built in-law suite with a private entrance typically returns 55 to 75 percent of cost at resale and can be rented if zoning allows — which is the difference between an expense and an asset.
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Frequently asked questions
How much does an in-law suite cost in Minnesota?
$80,000 to $220,000 in the Twin Cities. Converting existing space runs $60,000 to $160,000, while a new attached addition typically runs $150,000 to $300,000.
Can I add a second kitchen for an in-law suite?
It depends on your city's zoning, not the building code. Adding a range often converts the space into a second dwelling unit. A wet bar with a sink, refrigerator and microwave is allowed nearly everywhere.
What accessibility features should an in-law suite include?
36 inch doors, a curbless shower, blocking for future grab bars, lever handles, and a no-step entry. All of these cost far less during framing than as a retrofit.