ADU Builder in Utah: Basement Apartments & Backyard ADUs
ADU builder in Utah: basement apartments & backyard units
Add rental income or room for family. DreamBuilt builds internal ADUs (basement apartments) and detached backyard ADUs, including the permits, fire separation and separate entrances cities require.
An ADU (accessory dwelling unit) is a second, self-contained home on a single-family lot, with its own kitchen, bathroom and entrance. In Utah, a basement or internal ADU typically costs $60,000 to $150,000+ (about $100–$250 per sq ft), and a detached backyard ADU runs $200,000 to $400,000+ (Utah ADU Builders, June 2026). Utah law requires most cities to allow internal ADUs, and S.B. 284 (2026) requires most cities of 5,000+ residents to allow detached ADUs on qualifying single-family lots starting Oct. 1, 2026.
Two ways to add a unit
Basement apartments
Kitchen, bath, bedroom, egress and a separate entrance inside your existing home.
Detached backyard ADUs
A standalone cottage or garage apartment, subject to your city’s zoning.
City approval
We check your city’s ADU rules, parking and owner-occupancy requirements before you commit.
Fire & sound separation
Rated assemblies between units so the ADU passes inspection and stays quiet.
Separate utilities
Options for separate HVAC, water heater and electrical sub-panel.
Rental-ready finishes
Durable, easy-to-clean finishes that hold up to tenants.
How much does an ADU cost in Utah?
Utah planning ranges for 2026. Your written DreamBuilt bid is itemized for your home.
| ADU type | Cost per sq ft | Typical total |
|---|---|---|
| Basement / internal ADU | $100–$250 | $60,000–$150,000+ |
| Garage conversion | $125–$275 | $60,000–$175,000+ |
| Attached addition | $225–$375 | $150,000–$275,000+ |
| Detached backyard ADU / casita | $250–$450 | $200,000–$400,000+ |
| Prefab / modular (installed) | $225–$400 | $150,000–$300,000+ |
| Permits and plan review | — | $1,000–$5,000+ |
| Fire separation and egress | — | $5,000–$40,000+ |
| Electrical panel upgrade | — | $3,000–$15,000+ |
| Impact fees | — | $0 for an internal ADU inside an existing home |
Source: Utah ADU Builders, June 2026. Plan a 10–20% contingency. Basement ADUs cost the least because the structure, roof and foundation already exist. Timelines vary with the project and how much you customize it, and we finish most projects in 60 days or less.
Projects with ADU-ready spaces
Layton, UTLayton home renovation with finished basement
A Layton home renovated top to bottom, including a finished basement with a family room, bedrooms and a full bathroom, plus a refreshed kitchen.
See the project →
Sandy, UTSandy whole-home renovation
A Sandy home renovated throughout: a new white kitchen with granite counters, updated bathrooms, new flooring, and a finished lower level.
See the project →
Kaysville, UTKaysville bathroom remodel
A dated hall bathroom rebuilt with a marble-look tub surround, matte black fixtures and a new vanity.
See the project →One crew from walkthrough to final inspection
Walkthrough
We measure, check egress and mechanicals, and talk through how you’ll use the space.
Itemized bid
A written, line-item bid in 1 business day or less after your walkthrough. No vague allowances.
Plans & permit
We draw the plans and handle the permit based on your city’s requirements.
Build & inspect
Framing, mechanicals, insulation and inspections, with weekly photo updates.
Final walk
We walk every room with you and close out the punch list.
ADU questions
Are ADUs legal in Utah?
Yes. Utah law requires most cities to allow internal ADUs, like basement apartments, in primarily single-family zones, usually with owner-occupancy and parking rules. Since Oct. 1, 2026, S.B. 284 also requires most cities of 5,000+ residents to allow detached ADUs on qualifying single-family lots. Rules still differ by city, and we handle the permit based on your city’s requirements.
How much does a basement apartment cost in Utah?
Typically $60,000 to $150,000 or more, about $100–$250 per square foot (Utah ADU Builders, June 2026). Impact fees are $0 for an internal ADU built inside an existing home.
Do I need a separate entrance for a basement apartment?
Most cities require the unit to have its own entrance. It can be an exterior door or a shared vestibule, depending on local rules.
Can I rent out my basement apartment?
Usually yes, once it is permitted as an ADU. Some cities require registration or a rental license.
How long does an ADU take?
Timelines vary with the project and how much you customize it, and we finish most projects in 60 days or less.
What is the difference between an ADU and a mother-in-law apartment?
It is the same idea. “ADU” is the term Utah law and city codes use.
ADUs near you
Salt Lake County
5.0 stars from every homeowner who’s reviewed us
★★★★★
“Nathan and his team were awesome to work with! They communicated well. They were considerably cheaper than every other bid we got but the workmanship was great! Would definitely recommend using them”
— Ozzie J., Google review
★★★★★
“Nathan is thorough, timely, and an expert communicator. I’d recommend him to anyone for a basement remodel.”
— Jaden M., Google review
★★★★★
“Nathan and his team are amazing. They do great work especially with basement finishing. They did my basement and can I just say wow”
— Travis S., Google review
★★★★★
“Working with Nathan has been awesome. They’ve done a great job at keeping their timelines and doing what they said they were going to do.”
— Kayden C., Google review
Get your ADU estimate
Tell us about the space. We’ll schedule a walkthrough and send a written, line-item bid within 1 business day.
Or call 801-726-5692
Get a free, itemized estimate
Tell us about your space. We reply the same day, and your written, line-item bid arrives within 1 business day of the walkthrough.
Or call 801-726-5692