Garage Conversion & ADU in Round Rock, TX | 2026 Costs

What a Round Rock Garage Conversion Costs

A two-car garage is usually 380 to 440 square feet of space that already has a roof, slab and three walls. That existing shell is why a conversion costs less per square foot than new construction — but it also means real work: insulating walls and ceiling to code, replacing the overhead door with a framed wall and windows, leveling or adding flooring over a sloped slab, and extending HVAC, electrical and often plumbing.

A simple conditioned room with no plumbing sits at the low end. Add a full bathroom and a kitchenette with a sink, counters and cabinets and you're into the middle of the range. A detached ADU means a new foundation, roof, full utility runs and a separate service connection, so plan on more than a conversion for the same square footage.

• Conditioned bonus room or office, no plumbing: roughly $55,000–$70,000
• Guest suite with full bathroom: roughly $70,000–$95,000
• Full ADU-style unit with bathroom and kitchenette: roughly $95,000–$120,000+
• Detached new-build ADU: priced individually after site review — foundation, utilities and setbacks drive it
• Kitchen and bath finishes inside the unit follow our standard pricing; a compact kitchenette is far less than the $45,000 that a full kitchen remodel starts at

Timeline: Design First, Then One Construction Calendar

Design and permitting happen before anyone swings a hammer. That phase typically runs a few weeks and includes measured drawings, a finish schedule and the permit submittal. Once the permit is issued, we hand you a construction calendar and we build to it.

For scope comparison: a bathroom is typically 3 to 5 weeks and a kitchen 6 to 10 weeks. A garage conversion with a bathroom and kitchenette lands in a similar band to a kitchen — roughly 8 to 12 weeks of construction, driven by inspection scheduling and whether the electrical panel needs an upgrade. Detached ADUs take longer because of foundation cure time and separate utility work.

Permits and Inspections in Round Rock

Round Rock is its own permitting jurisdiction, not City of Austin. Converting a garage into living space is a change of use, so it needs a building permit through the City of Round Rock, with electrical, plumbing and mechanical trade permits as applicable. Expect inspections at rough-in (framing, electrical, plumbing, mechanical) and again at final before the space can be legally occupied.

Two Round Rock-specific items catch homeowners off guard. First, converting the garage removes covered parking, and the city reviews whether your driveway and lot still meet off-street parking requirements. Second, if your property sits in an HOA — and most Round Rock subdivisions do — the HOA's architectural committee approval is separate from the city permit and should be secured before design is locked in. Detached ADUs also have to clear setbacks, lot coverage and impervious-cover limits.

We handle the permit paperwork and inspections. Our team pulls City of Austin permits on jobs inside Austin and works the same way with Round Rock and Williamson County when the address falls there. Unpermitted conversions are the most common problem we're called to fix — they fail appraisals, complicate a sale and can't legally be rented.

• Building permit for change of use from garage to habitable space
• Electrical, plumbing and mechanical permits as the scope requires
• Rough-in and final inspections before occupancy
• Parking review when covered parking is eliminated
• HOA architectural approval, handled separately from the city
• Setback, lot coverage and impervious cover review for detached ADUs

How Our Fixed-Price Design-Build Process Works

We design, price and build the project with one contract and one point of accountability, so there's nobody to blame when a drawing doesn't match the field. The sequence is simple: site visit and measurements, design and finish selections, a fixed price in writing, permit submittal, then construction.

Fixed price means the number on your contract is the number you pay unless you ask for a change or we open a wall and find something nobody could see — rotted sill plate, aluminum wiring, a slab that won't take a drain. In those cases we price the fix in writing before we proceed. No cost-plus, no open-ended allowances buried in the fine print.

Our carpenters are in-house employees, not day-rate subs rotating off to another job. That's how we hold a schedule and how we can back the work with a 5-year workmanship warranty. Financing is available if you'd rather not tie up cash or tap equity.

Choosing a Contractor for a Round Rock ADU

The cheapest bid on a garage conversion is usually the one that skipped the permit, skipped ceiling insulation or left the HVAC undersized. Any of those shows up later as a hot, humid room over an uninsulated slab that nobody wants to sleep in.

Ask any contractor you're considering these questions before you sign.

• Is the price fixed in writing, or is it an estimate that can move?
• Who pulls the Round Rock permit — you or me?
• How are you insulating the slab, walls and ceiling, and how is the space conditioned?
• Are your framers and finish carpenters employees or subcontractors?
• What does your workmanship warranty cover, and for how long?
• When does construction start and what is the day-by-day calendar?

Is the Rental Math Worth It?

Round Rock homeowners usually look at an ADU for one of three reasons: aging parents or adult kids who need their own door, a quiet office away from the house, or rental income. All three work, but the finishes should match the use. A long-term rental needs durable flooring, a real bathroom and sound separation from the main house. A home office can skip the kitchenette entirely and save you real money.

Before you commit, check your deed restrictions and HOA rules on rentals — a legally permitted ADU can still be restricted by the neighborhood from being leased. We'd rather flag that during design than after you've spent the money.

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