Basement Apartment & ADU

A basement apartment is one of the smartest financial moves a Utah homeowner can make. With average rents in the Salt Lake metro running $1,200–$1,800/month for a one-bedroom, a well-built basement apartment can pay for itself in 2-4 years — and then it’s pure income. Or it can house aging parents, adult children saving for a home, or provide flexible living space for your family.

Utah has become increasingly ADU-friendly in recent years. State legislation (HB 82, passed in 2021) requires most municipalities to allow internal ADUs (like basement apartments) in residential zones. That’s good news for homeowners looking to build.

Utah Basement Finishing designs and constructs legal, permitted basement apartments, accessory dwelling units (ADUs), and mother-in-law suites throughout Salt Lake, Utah, Davis, and Weber counties. We handle design, permits, construction, and all the regulatory navigation so you end up with a unit that’s both livable and legal.

What We Offer

Full Basement Apartment / ADU

• Separate entrance — exterior door with its own address (required for legal ADUs in most municipalities). Walkout basements are ideal; for non-walkout basements, we create entrances through garage conversions or side-of-house stairwells
• Full kitchen — range/cooktop, refrigerator, sink, dishwasher, cabinetry, and countertops
• Bedroom(s) — one or two bedrooms with egress windows and closets
• Full bathroom — toilet, vanity, shower or tub/shower combo
• Living room — open-concept or defined space
• Laundry — washer/dryer hookups or stackable in-unit
• Mechanical separation — separate HVAC zone (mini-split or zoned ductwork), separate electrical sub-panel, separate water heater (or shared with metering)
• Fire separation — 1-hour fire-rated assembly between the apartment and the main dwelling (required by code). Fire-rated drywall, self-closing fire-rated door to common areas, interconnected smoke detectors
• Sound insulation — critical for both tenant comfort and your sanity. We install R-19 batts plus resilient channel in the ceiling assembly between units

Mother-in-Law Suite

Similar to a full apartment but designed for family rather than tenants:

• Connected to the main home (shared entrance is acceptable for family suites)
• Kitchenette or full kitchen depending on preference
• ADA-friendly options — wider doorways (36″), grab bars, curbless shower, lever handles, comfort-height toilet
• Emergency alert system wiring
• Intercom or doorbell connection to the main home

ADU Regulatory Navigation

• Zoning research — we verify ADU eligibility for your specific property (zone, lot size, parking requirements)
• Permit application — complete plans showing floor plan, fire separation, egress, electrical, plumbing, and HVAC
• Impact fee research — some municipalities charge impact fees for new ADU units ($2,000–$10,000+). We identify these upfront
• Utility requirements — some jurisdictions require separate utility meters or connections. We coordinate with utility providers
• Occupancy limits — Utah code limits ADU occupancy in some zones (typically to family members or a single unrelated occupant). We clarify restrictions for your municipality
• Business license — some cities require a rental business license for ADU rentals. We’ll let you know what’s needed

Our Process

Step 1: Feasibility Assessment

We evaluate your basement for ADU potential — ceiling height (minimum 7 feet), separate entrance feasibility, plumbing access, electrical panel capacity, and lot/zoning requirements. Not every basement can become a legal apartment, and we’ll tell you upfront if yours can or can’t.

Step 2: Design and Permitting

We create a full apartment floor plan with kitchen, bathroom, bedroom(s), living area, laundry, and storage. Plans include fire separation details, egress windows, electrical load calculations, and HVAC design. We submit to the building department and manage the review process.

Step 3: Construction

Full buildout: framing, fire-rated assemblies, plumbing (kitchen, bathroom, laundry), electrical (sub-panel, dedicated circuits, smoke/CO interconnection), HVAC, insulation, drywall, flooring, cabinetry, fixtures, and exterior entrance. Timeline: 8-14 weeks depending on scope.

Step 4: Inspections and Certificate of Occupancy

Multiple inspections throughout construction (framing, fire separation, rough plumbing, rough electrical, insulation, final). After the final inspection, you receive a certificate of occupancy — the legal document that allows you to rent the unit.

Cost Range

Major cost components:

• Kitchen: $10,000–$25,000 (cabinetry, countertops, appliances, plumbing)
• Bathroom: $8,000–$18,000
• Separate entrance construction: $5,000–$15,000
• Fire-rated assemblies: $3,000–$8,000
• Electrical sub-panel and wiring: $4,000–$8,000
• Mini-split HVAC: $3,000–$6,000
• Egress windows (per window): $3,500–$6,000
• Permits and impact fees: $2,000–$12,000

Return on Investment

At Utah’s current rental rates:

• 1-bedroom basement apartment: $1,200–$1,600/month rent
• Annual gross income: $14,400–$19,200
• Payback period on a $65,000 build: 3.5–4.5 years
• After payback: Net income (minus expenses) of $10,000–$15,000/year

Why Choose Us for Basement Apartments

• ADU regulatory expertise — we know which Utah cities allow ADUs, their specific requirements, and how to navigate the permitting process
• Fire separation compliance — the 1-hour fire-rated assembly between units is the most inspection-critical element. We build it right every time
• Full-service construction — kitchen, bathroom, bedroom, electrical, plumbing, HVAC, and separate entrance all handled by one contractor
• Soundproofing priority — we invest in proper acoustic separation because a noisy apartment creates problems for both the tenant and the homeowner
• Rental-ready quality — we build apartments that attract quality tenants. Good finishes, functional layouts, and professional workmanship mean fewer vacancies and maintenance calls

Frequently Asked Questions

Is a basement apartment legal in Utah? In most cases, yes. Utah’s HB 82 (2021) requires cities to allow internal ADUs (including basement apartments) in residential zones. However, specific requirements vary by municipality — lot size minimums, parking requirements, owner-occupancy rules, and impact fees differ from city to city. We research your specific situation before starting.

Do I need a separate entrance for a basement apartment? For a legally rentable ADU, most municipalities require a separate entrance that doesn’t pass through the main dwelling. For a mother-in-law suite occupied by family, a shared entrance is typically acceptable. We’ll clarify requirements for your city.

What’s the difference between an ADU and a mother-in-law suite? Functionally, they’re similar. Legally, an ADU is a separate dwelling unit with its own entrance, kitchen, and bathroom that can be rented to non-family members. A mother-in-law suite is typically an internal living space designed for family that may share an entrance with the main home. ADUs require more stringent fire separation, separate utilities (in some jurisdictions), and permits.

Do I have to live in the home to rent a basement apartment? Many Utah municipalities require owner-occupancy — meaning the homeowner must live in either the main house or the ADU. Some cities have relaxed this requirement. We verify the specific rules for your property.

Will building a basement apartment increase my property taxes? Potentially. Adding a legal ADU increases your home’s assessed value, which may increase property taxes. However, the rental income typically far exceeds any tax increase. Consult with your tax advisor for specifics.

Can I use my basement apartment for Airbnb/short-term rental? It depends on your city’s short-term rental regulations. Some Utah cities allow short-term rentals in ADUs with a business license; others restrict ADUs to long-term rentals only (30+ days). Salt Lake City, for example, has specific short-term rental licensing requirements. We’ll point you in the right direction for your jurisdiction.

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Start generating rental income from your basement. Call 801-515-3473 for a free ADU feasibility consultation.

Utah Basement Finishing — 369 E 900 S #235, Salt Lake City, UT 84111 | Mon–Sat 8am–6pm