How We Finished an 1,800 Sq Ft Basement ADU in Tooele, Utah

We recently wrapped up a basement finish in Tooele that I wanted to write about because it's a good example of what this kind of project actually looks like from start to finish. The homeowners had been in their house about three years with the basement sitting unfinished. They finally decided to pull the trigger and turn it into a rental unit — a full ADU they could lease out to a family.

The basement was about 1,800 square feet, and the builder had already put in a walk-out, so that was one less thing to deal with. Here's how the whole thing went.

What the Homeowners Wanted

They weren't looking for a basic basement finish. They wanted something a tenant would actually want to live in long-term. That meant a real kitchen, not a kitchenette. A proper primary suite with a nice bathroom. Enough bedrooms to accommodate a family. And they wanted the finishes to be nice — not the cheapest thing on the shelf.

Our first step is to take the wants of the customer and lay them out in CAD to help visualize the space and make sure it all fits together cohesively. Here’s what we came up with for this customer: a primary bedroom big enough for a king bed and furniture, with a bathroom that included a walk-in closet, large tiled shower, double vanity, and a separate water closet. A full kitchen with an island, all appliances, and a dining area big enough to actually eat in. Two additional bedrooms that work well for kids. And a laundry closet — we found a dead-end hallway space and tucked a stackable washer and dryer in there with shelving for cleaning supplies.

After a couple tweaks to the layout they were happy with it, we agreed on pricing, signed a contract, and got started.

The Build

Framing came first. Our framing crew had all the walls done in a few days once the layout was set.

Mechanical rough-in is where it gets more involved. The home was only plumbed for one bathroom when we started. Adding a full primary bath, a kitchen, and a laundry closet meant the plumber had to run new drains and supply lines for all of it. The electrician followed to rough in all the lighting, receptacles, and 220V circuits for the kitchen and laundry. Then the HVAC sub tied the new space into the existing unit with new supply lines and returns. Once mechanical rough-in was done we called for our 4-way inspection with the city. Passed without any issues.

Before drywall went up we installed sound insulation in the ceiling and sound dampening rails under the drywall. This was an upgrade the homeowners asked for and I think it was a smart call. When you've got two households living in the same structure, sound transfer is a real issue. These two steps make a noticeable difference. The homeowner wanted to make sure both units were comfortable and had ample privacy and the sound dampening products we installed made a big difference.

Drywall is usually the longest phase of any basement finish — delivery, hang, tape, mud, texture — and doing it right takes time. Getting the seams smooth and the texture consistent is one of those things that shows up later if it's done wrong.

Flooring and tile came next. We waterproofed the shower pan in the primary bath and the tub surround in the hall bathroom and tested them before setting any tile. LVP in the kitchen and dining area, tile in the bathrooms. Trim carpentry after that — doors hung, casing and baseboard throughout, custom closet organization in the primary suite's walk-in, two linen closets, and shelving in the laundry closet.

Paint. The homeowners picked a greyish-green wall color with white trim. It turned out great. The wall color really made the tall, white, craftsman trim pop!

Cabinetry was delivered for the kitchen and both bathrooms. Same day we had countertops templated, and about a week later the quartz was in. The plumber came back to install all the fixtures — matte black throughout: showers, tub, sinks, and kitchen. They also added a touchless sprayer in the kitchen. Electrician followed right behind and had all the light fixtures, can lights, and receptacles done in about a day. Appliances were delivered and the kitchen was complete.

Final details — carpet in the bedrooms and living area, door hardware, HVAC vent covers, towel bars, glass shower doors, mirrors.

We do our own walkthrough before we ever bring the homeowner in. Whatever we find on our list gets taken care of first. Then we walk the homeowners through, blue tape anything that needs a touch-up, clean those up, and call for final inspection. Passed. Certificate of occupancy issued.

Cost and Timeline

This project came in right around $75 per square foot. That's on the higher end of what we do, and the scope explains it — full primary suite, full kitchen, custom tile work, upgraded fixtures throughout, sound insulation, and the laundry closet. A more standard finish with a living area, one bathroom, and a couple bedrooms typically runs $35–$55 per square foot depending on finishes.

Total time from framing to final inspection: 11 weeks.

How It Ended Up

They had the unit rented to a family within a few weeks of getting their certificate of occupancy. Three years of an empty basement, and now it's generating rental income every month. That's a pretty good outcome that everyone is pleased with!