Garage Conversion & ADU in Buda, TX: 2026 Cost Guide

What a garage conversion or ADU costs in Buda

Garage conversion pricing splits cleanly by how much plumbing and mechanical work is involved. Finishing the box — framing the old door opening, insulating the walls and roof, leveling and finishing the slab, drywall, electrical, flooring, trim and conditioned air — is the base scope. Every fixture you add past that moves the number.

Here is how we price the three common versions in Buda, and a detached unit for comparison:

• Conditioned flex room, office or bedroom, no plumbing: $45,000–$75,000. Includes infill of the garage door opening, insulation, drywall, electrical, flooring, trim, paint and an HVAC solution.
• Conversion with a full bathroom and kitchenette: $75,000–$120,000. Adds drain lines cut into the slab, supply lines, a water heater, exhaust ventilation and cabinetry.
• Full attached ADU with its own entrance, kitchen, bath and laundry: $120,000–$180,000. Kitchen scope inside it follows our published kitchen ranges — $45k–$70k for cabinets, counters, lighting and fixtures in a compact footprint.
• Detached new-build ADU, roughly 500–900 sq ft: $180,000–$320,000+. New slab, framing, roof, windows, separate utility runs, site work.
• Keeping a garage bay: a partial conversion that preserves one parking bay runs at the lower end of the first two ranges but needs a firewall detail and a new wall — budget $8,000–$15,000 for the separation work itself.

What moves your number up or down

Two houses on the same Buda street can land $30,000 apart on the same square footage. These are the variables that do it.

Ask for each of these to be priced as a line item, not folded into a lump allowance you can't see.

• Slab condition and height. Garage slabs are usually poured lower than the house slab and sloped toward the door. Raising and leveling the floor, or building an insulated subfloor over it, typically adds $4,000–$9,000.
• Plumbing runs. Cutting and trenching the slab for a bathroom drain, then tying into the main line, typically adds $9,000–$18,000. How far the garage sits from the existing stack drives that.
• HVAC approach. A dedicated mini-split for one room typically runs $4,500–$8,000 installed. Extending the main system is sometimes possible but depends on whether the existing equipment has capacity, which we check before pricing.
• Electrical capacity. If the panel is full, a subpanel typically runs $2,000–$4,500, and a service upgrade more. Many Buda subdivision homes from the 1990s and 2000s have room; older homes near downtown often do not.
• Windows and exterior finish. Infilling the garage door opening with siding, stone or stucco to match the rest of the elevation, plus two windows, typically runs $7,000–$14,000. Matching 20-year-old stone is the part people underestimate.
• Separate entry and egress. A new exterior door, landing and path typically adds $3,500–$7,000.
• Finish level. Tile versus LVP, stock versus custom cabinetry, quartz versus laminate — the gap between a rental-grade and a high-end interior on the same floor plan is routinely $20,000 or more.
• Detached only: site work. Trenching water, sewer and power across the yard, plus a new driveway or path, typically adds $15,000–$40,000 depending on the run length and what's in the way.

What's particular about this work in Buda

Most of the garages we convert in Buda sit under newer subdivision homes — attached two-car garages on slab-on-grade foundations, built from the 1990s onward, in neighborhoods off FM 1626, FM 2001 and the Main Street corridor. That's generally good news: the framing is modern, the roof lines are simple, and the garage is usually attached directly to conditioned space, which keeps HVAC and plumbing runs short.

The Central Texas clay soil is the thing to respect. Garage slabs move, and a slab that has cracked or heaved needs to be assessed before anyone prices flooring over it. If we see movement, we bring in a licensed engineer — an engineer and the permit office decide what the slab and any framing changes require, not us and not you.

Climate drives the mechanical scope. A Buda garage is an uninsulated oven from June through September. Converting it properly means insulating the walls, the ceiling or roof deck, and the old garage door opening, then sizing cooling for a room with a lot of exterior surface. Skipping insulation to save money produces a room nobody uses in August.

Two local items to check early. First, many Buda subdivisions have HOA covenants that govern exterior changes — losing a visible garage door, adding a detached structure, or changing siding often needs architectural committee approval, and that review takes its own calendar time. Second, your address matters: homes inside Buda city limits are reviewed by the city, and homes in unincorporated Hays County go through the county. Properties on septic have additional review of the system's capacity before any new bathroom or kitchen is added. We confirm which applies to your parcel at the first visit.

Permits, inspections and who decides what

Changing a garage into living space is a permitted scope of work, and so is a detached ADU. We prepare and submit the application, carry it through review, and schedule the inspections. You do not chase paperwork.

What that typically involves: a submitted plan set showing the new floor plan, wall sections, insulation, electrical and mechanical layout; review by the jurisdiction with authority over your address; then inspections at the rough stage — framing, electrical, plumbing, mechanical — and again at final before the space is signed off. Permit and review fees for this kind of project typically run $800–$3,500 depending on scope and jurisdiction, and we show them as a line in your fixed-price contract rather than a surprise later.

A few decisions are not ours to make, and you should be suspicious of any contractor who tells you otherwise on a first visit. Whether a wall can be modified, what the slab needs, how setbacks and lot coverage apply to a detached unit, whether the unit may be rented, and whether a kitchen is permitted in the structure — a licensed engineer and the permit office decide those. We get the questions in front of them early, before you sign, so the answers shape the design instead of blowing it up mid-build.

Parking is the other item worth raising at the start. Converting both bays changes where cars go, and that can interact with both the jurisdiction's review and your HOA's rules. We raise it in design rather than at inspection.

Timeline: first visit to finished space

Design and permitting happen before demolition, so the construction calendar we hand you is the one we build to. We don't give start dates in a guide — but here is the realistic shape of the project in weeks.

Total: roughly 16–28 weeks from first visit to a finished attached conversion, and 9–14 months for a detached ADU. The construction half is predictable. The review half is where honest estimates vary, which is why we price and schedule it separately.

• Week 1: site visit. We measure, look at the panel, the slab, the HVAC equipment and the drain locations, and confirm your jurisdiction.
• Weeks 2–5: design and scope. Floor plan, elevations, finish selections, mechanical approach. This is where you make the choices that set the price.
• Week 5–6: fixed price in writing. One number, line-itemed, including permit fees and allowances that are real numbers rather than placeholders.
• Weeks 6–14: permitting and any HOA architectural review. These can overlap. Detached ADUs take longer here than attached conversions.
• Construction, attached conversion: 8–14 weeks. Demolition and slab prep, framing and door infill, rough-in and inspections, insulation and drywall, finishes, final inspection.
• Construction, conversion with a full bath and kitchen: 12–18 weeks. The bathroom portion alone follows our usual 3–5 week bathroom pace; the kitchenette or kitchen follows our 6–10 week kitchen pace, run concurrently where sequencing allows.
• Construction, detached ADU: 5–8 months, in line with a whole-home renovation at 4–8 months.
• Final week: punch list walkthrough, then the 5-year workmanship warranty paperwork.

How our fixed-price design-build process works, and what to ask any contractor

We design and build with in-house carpenters, which means the person who drew the wall is accountable to the person who frames it. Before any demolition, you get a fixed price in writing — not an estimate that drifts. Change orders exist only when you change your mind or when something behind the drywall genuinely isn't what the drawings showed, and they're written and signed before the work happens. Financing is available if you'd rather not pull the whole project out of savings.

The workmanship warranty runs 5 years. Permits are handled as part of the contract. If you're interviewing other builders in Buda, these are the questions that separate the ones who will finish from the ones who won't:

• Is the price fixed in writing before demolition, and what specifically triggers a change order?
• Who is holding the permit and scheduling the inspections — you, or me?
• Are the crews employees or subcontracted day to day? Who is on site every morning?
• How is the slab being assessed, and who makes that call if there's movement?
• What is the HVAC plan, with equipment sizing, not just 'we'll add a mini-split'?
• What are the allowances for flooring, tile, cabinets and fixtures, in dollars per square foot or per unit?
• What is the workmanship warranty, in years, and what does it exclude?
• What happens to the exterior where the garage door was, and how will the siding or stone be matched?
• Next step: get your parcel's jurisdiction confirmed and your HOA covenants pulled before you talk to anyone about design. Those two documents decide more about your project than any finish selection will.

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