# Garage Conversion & ADU in Bee Cave, TX: 2026 Cost Guide

By the Home Remodel Pro team · published 2026-11-02 · Garage Conversion & ADU, Bee Cave

A garage conversion in Bee Cave typically runs $55k–$95k for a finished room with heating and cooling and a bathroom, and $85k–$145k when it becomes a true accessory dwelling unit with its own kitchen, bath and entry. A detached ADU built from the ground up usually starts around $225k and climbs past $350k depending on size, site access and utilities. Below is what moves a project inside those ranges, how review and inspections work in Bee Cave, and the week-by-week calendar from first visit to final walkthrough.

## What a Bee Cave garage conversion or ADU actually costs

Price is driven by three things: how much of the existing shell you keep, whether the space gets a kitchen, and how far water, drain and power have to travel. A two-car garage that already sits under the main roof, on the same slab, with the panel on the adjacent wall is the cheapest version of this project. A detached unit at the back of a sloped Hill Country lot, with a new foundation and a 60-foot utility run, is the most expensive.

We put a fixed price in writing before anything is demolished. That number covers labor, materials, our in-house carpentry, and the permit submittal — so you are not watching a meter run.

Typical Bee Cave ranges:

- Garage to conditioned living space (office, guest room, gym) — $55k–$95k. Includes insulation, drywall, flooring, electrical, a dedicated HVAC solution, and infilling or replacing the garage door opening.
- Garage to full ADU with kitchen and bath — $85k–$145k. The bathroom and the kitchen plumbing are what move the number; cutting and re-pouring slab for drain lines is real work, not a line item you can wish away.
- Detached new-build ADU, roughly 500–900 sq ft — $225k–$375k+. Foundation, framing, roof, windows, full mechanical, electrical and plumbing, plus the site work to get there.
- Add $8k–$20k if the electrical service has to be upgraded to carry a second dwelling.
- Add $6k–$18k for long utility trenching across rock, which is common on Bee Cave lots.
- Add $10k–$30k for a finish level that matches a custom main house — real wood cabinetry, tile to the ceiling, upgraded windows.

## What is particular about this work in Bee Cave

Bee Cave sits on Hill Country limestone. Trenching for a sewer line, a water line or a new foundation often means hitting rock within the first couple of feet. That is not a problem, it is a cost: rock excavation is slower and uses different equipment than digging in black clay. We get the site looked at before we price, so the trenching allowance in your contract reflects your lot, not an average.

Lots here are frequently sloped and wooded. A detached ADU behind the house may need a retaining element, a stepped foundation, or a path for a concrete truck and a material drop. If a crane or pump is needed because the back yard is not reachable by truck, that belongs in the fixed price up front, not in a change order in month three.

Most Bee Cave neighborhoods are governed by an HOA with an architectural review committee. Expect to submit elevations, siding and roofing selections, and a site plan showing setbacks before you build — and expect that review to run on its own schedule, in parallel with the municipal review. We build the drawings so one package satisfies both.

Utilities vary by where you are. Some properties are on a public sewer, others on an on-site septic system. Whether an existing septic system can serve a second dwelling, and what that takes, is determined by the permitting and health authority with jurisdiction over your address — not by a contractor's opinion. We get that question answered in the design phase, before you have spent money on a plan that cannot be approved.

Finally, summers here are long and hot. A garage slab and uninsulated walls that were fine for storing a car will not hold a comfortable room in August. Spray foam or dense insulation at the roof deck, a correctly sized mini-split or a tie-in to the main system, and attention to the old garage door opening are the difference between a usable ADU and a hot box.

## Permits, review and inspections

Converting a garage or adding a second dwelling is permitted work. Your project is reviewed by the jurisdiction your address falls under — the City of Bee Cave, with Travis County involvement where it applies — and we prepare and submit that package for you. We also handle City of Austin permits for the parts of our service area inside the city, so the submittal process itself is routine for us.

Whether a second dwelling is allowed on your lot, how large it may be, where it can sit relative to property lines, how many parking spaces must remain, and whether impervious cover limits are a factor are all decided by the reviewing jurisdiction based on your zoning and plat. We find out in writing during design rather than guessing.

Anything involving removing a wall, cutting a new opening, or changing how the roof is carried is designed by a licensed engineer and approved by the permit office. We do not make that call on site, and you should be skeptical of anyone who does.

Expect permit fees in the range of $900–$3,500 for a garage conversion and $2,500–$7,000 for a detached ADU, with utility or impact-related fees possible on top depending on your address. Those are passed through as itemized line items, not marked up into a vague allowance.

Inspections happen in a set order, and the job stops at each one until it passes:

- Plan review and approval, with any HOA architectural approval running alongside
- Foundation or slab-cut inspection, before concrete
- Rough-in: framing, electrical, plumbing and mechanical, all inspected before anything is covered
- Insulation and energy inspection
- Final inspection, which is what makes the space legal to occupy

## The timeline, week by week

Design and permitting happen before demolition, so the construction calendar we hand you is the one we build to. Here is a realistic sequence. We do not promise a start date before a contract is signed and the permit is in hand.

Garage conversion:

- Weeks 1–2: site visit, measurements, scope conversation, and a fixed-price proposal
- Weeks 2–6: design, selections, engineering if an opening is being changed, and HOA submittal
- Weeks 6–12: permit submittal and review (timing is the jurisdiction's, not ours)
- Weeks 12–22: construction. A conditioned room without plumbing is usually 6–9 weeks. A full ADU with a kitchen and bath is usually 10–16 weeks, because the bathroom alone is the 3-to-5-week scope we quote on standalone bathrooms and the kitchen runs on its own sequence
- Final week: punch list, final inspection, walkthrough, warranty paperwork

## How our fixed-price design-build process works

One company does the drawings, pulls the permit, and swings the hammers. There is no handoff where a designer's plan meets a builder's objection and you pay for the gap.

First visit: we walk the garage or the site, look at the panel, the slab, the roof line and the route for utilities, and talk about how you intend to use the space — guest suite, rental, office. Then design: drawings, engineering where it is needed, and the selections that actually drive cost. Cabinets, tile, windows and the HVAC approach get decided here, not mid-build.

Then the fixed price. One number, in writing, with the scope itemized, before demolition. The only things that change it are things you add, or a condition hidden behind a wall that nobody could see at the walkthrough — and those come to you as a written change order you approve before work continues.

Our carpenters are in-house, which is why the finish carpentry in a 600-square-foot ADU looks like the finish carpentry in the main house. Workmanship is covered by a 5-year warranty. Financing is available if you would rather not pay out of savings.

A detached ADU is a longer build: expect 5–8 months of construction after permitting, which puts it in the same calendar territory as the 4-to-8-month whole-home renovations we run.

## What to ask any contractor before you sign

Bring the same questions to everyone you talk to. The answers will sort the field quickly.

If a contractor tells you on the first visit that a wall can come out, or that no permit is needed, stop. Those are decisions for a licensed engineer and the permit office, and getting them wrong shows up when you try to sell the house.

Next step: get photos of your garage interior, your electrical panel, and the outside wall where the utilities would run, plus a copy of your survey or plat if you have one. With those three things we can have a useful first conversation about whether a conversion or a detached unit is the better fit for your Bee Cave lot, and what the fixed price is likely to look like.

- Is the price fixed in writing before demolition, and what specifically is excluded?
- Who prepares and submits the permit package, and who attends the inspections?
- Who is doing the framing and finish carpentry — employees or whoever is available that week?
- How is rock excavation handled if the trench hits limestone?
- What is the plan for heating and cooling the converted space, and is it sized for an August afternoon?
- What does the workmanship warranty cover, and for how long?
- If a change order comes up, what does the approval process look like before work continues?

## Bee Cave homeowners also ask

### Can I build an ADU on my lot in Bee Cave?

That depends on your zoning, your plat, setbacks, impervious cover and parking — and it is decided by the reviewing jurisdiction for your address, not by a contractor. We confirm it in writing during the design phase, before you pay for a full set of drawings. HOA architectural approval is a separate review in most Bee Cave neighborhoods and runs alongside it.

### How much does it cost to turn a two-car garage into a rental unit?

Expect $85k–$145k for a full ADU with a kitchen, a bathroom, its own entry and dedicated heating and cooling. The bathroom plumbing and any slab cutting for drain lines are the biggest single drivers. If you only want a conditioned office or guest room with no kitchen, the range is $55k–$95k. You get one fixed number in writing before demolition.

### How long does a garage conversion take from the first phone call?

Plan on roughly 3–5 months total for a conversion: 1–2 weeks to price it, 4 weeks of design and selections, then permit review, then 6–16 weeks of construction depending on whether there is a kitchen and bath. A detached ADU is 5–8 months of construction after permitting. We do not commit to a start date until the contract is signed and the permit is issued.

### Will I lose parking, and does that matter?

Converting an attached garage removes covered parking, and whether your lot must keep a certain number of spaces is a zoning question the permit office answers for your address. Many Bee Cave homeowners add a carport or extend the driveway as part of the same project — tell us early, because it affects the site plan we submit and the fixed price we write.

## Check it with Bee Cave's own pages

Permit rules and fees change, and the office that issues the permit is the authority on them, not this guide.

- [City of Bee Cave — building permits and inspections](https://www.beecavetexas.gov/government/departments/planning_development/building/index.php)

What a garage conversion or ADU in Austin involves: https://www.homeremodelpro.com/austin/garage-conversion-adu

## Get a free estimate

- Call (512) 601-5666 (Monday to Friday 8am–6pm and Saturday 9am–2pm); a project consultant calls back within one business hour.
- Request an estimate online: https://www.homeremodelpro.com/austin#quote
- 5-year workmanship warranty · one fixed price in writing · in-house carpenters · permits and inspections included

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Source: https://www.homeremodelpro.com/austin/blog/garage-conversion-and-adu-bee-cave-guide · Home Remodel Pro Austin, TX