A garage conversion is usually the fastest, most affordable path to an ADU in Utah, but "convert the garage" undersells how much actual construction work is involved in turning an unheated storage space into a fully legal, code-compliant home.
Before any conversion work starts, we assess the garage's existing foundation, framing, and roof structure. Most garage slabs weren't poured to residential living-space standards, and framing sized for a garage door opening often needs reinforcement once that opening is closed in and load paths change. This assessment determines how much of the existing structure can stay versus what needs to be rebuilt.
Building code requires habitable rooms to have a minimum finished ceiling height of 7 feet across at least half the room's floor area, with a reduced 6'8" minimum allowed in bathrooms and similar spaces. Many garages were built with lower ceiling heights than this, especially older ones, which can mean adjusting the roof structure or excavating the slab, both of which add cost and complexity beyond simply insulating and drywalling.
Any room used as a sleeping area needs a code-compliant emergency egress opening: a minimum 20 inches wide, 24 inches tall, at least 5.7 square feet of net clear opening, with a sill no higher than 44 inches above the floor. A code-compliant exterior door (at least 32 inches wide and 78 inches tall) can also satisfy this in some layouts. Garages typically have a single large garage-door opening and maybe one small side window, neither of which meets egress requirements as-is, so cutting a new, properly sized window opening into the wall is standard scope on almost every garage conversion.
A garage is built to store cars, not to be comfortable to live in. Garage conversions require full wall, ceiling, and often slab insulation upgrades to meet residential energy code, plus proper vapor barriers and air sealing. Skipping or underbuilding this step is the single most common reason a converted garage feels noticeably colder or hotter than the rest of the house after the work is "done."
Because a garage is typically attached to or very close to the main house, utility runs for water, sewer, gas, and electrical are usually short and relatively affordable compared to a detached backyard ADU — see our full utility hookup guide for how each system typically connects.
Garage conversions typically run $50,000-$120,000 depending on the scope of structural, ceiling height, and insulation work required, and take about 2-3 months from permit approval to completion — the fastest of the three ADU types we build. See our full cost breakdown by ADU type for how this compares to modular and custom stickbuilt options.
The properties where a garage conversion works best have decent existing ceiling height, a garage close to existing utility hookups, and structure that doesn't need a full rebuild. We'll tell you honestly during your free site visit if your garage is a great candidate or if a different ADU type would actually save you money.