Trusted ADU for San Antonio Homeowners
Adding an ADU in San Antonio means navigating city development codes, utility connections, and foundation work on Texas clay soil. We handle the whole process, from permit drawings through final inspection. The Garrison Standard family has been building and managing ADU projects since 2010, and every job gets a written scope and price before the first tool touches your property. No allowances that quietly expand. No crews that disappear after framing. If you’re planning a backyard unit, garage conversion, or detached studio apartment, call us at (409) 215-3468 to schedule a site walk.
What Our ADU Service Includes
Every ADU project moves through the same disciplined sequence, whether you’re converting a garage off Broadway or building a detached unit behind a 1950s ranch in Jefferson. We manage the city application, the construction, and the close-out. Here’s exactly what the work covers.
Feasibility and Site Assessment
Before any drawings happen, we walk the property to check setbacks, drainage, and utility access. San Antonio’s development code allows ADUs on most single-family lots, but your specific zoning district and lot shape determine square footage limits and height restrictions. We measure the hard numbers so you don’t pay for architecture that the city rejects. The written report tells you what fits, what it will likely cost, and what the permit timeline looks like for your specific part of town.
Permitting and Plan Approval
San Antonio requires building permits for ADUs, and the review process involves zoning checks, plan review, and sometimes historic district approval depending on your location. We prepare and submit the permit package, respond to plan reviewer comments, and track the application until the permit is issued. You won’t spend afternoons at the Development Services office. Our team handles the back-and-forth with the city so your project doesn’t stall over paperwork.
Foundation and Utility Connections
San Antonio sits on expansive clay that moves with seasonal moisture. Detached ADUs need foundations sized for that movement, and we specify the right slab or pier system for your soils. Water, sewer, and electric connections run through the city’s utility coordination process, which means SAWS and CPS Energy signoffs. We arrange those connections so your unit has its own metering or a properly permitted sub-panel, not a buried extension cord from the house.
Framing, Roofing, and Exterior Finishes
Once the slab is in, we frame the structure, dry it in with roofing and siding, and weather-seal the envelope before any interior work starts. We use materials that hold up under Texas sun and the occasional hailstorm, and we match the visual character of your neighborhood. The framing inspection happens before insulation goes in, so you know the bones passed code before they get covered.
Interior Build-Out and Final Inspection
The inside comes next: drywall, flooring, kitchenette or full kitchen, bathroom, HVAC, and finishes. For a garage conversion, this phase includes upgrading the envelope to meet residential energy code, which usually means new insulation, electrical, and possibly a window change. We coordinate the final city inspection, close out your permit, and hand you a unit that’s ready to rent or welcome family. Every project carries our 365-Day Done Right Promise in writing.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Brands We Service for ADU
An ADU often shares systems with your main house, especially when it’s attached or built over a garage. We plan for the equipment you already have and the new fixtures we install. If your ADU includes a garage space, we work with Amarr and Clopay door lines regularly, and we know their wind-load ratings and opener compatibility well enough to spec the right door for a living space above or beside it.
For converted garages that keep their original door, we’ve reconditioned Wayne Dalton and Raynor units to function as an insulated wall rather than a leaky service door. The model matters less than the installation, but when you have an existing Craftsman opener or torsion assembly, we can usually reuse the track and hardware even after the space becomes a bedroom or office. Whether your ADU keeps a garage function or fully converts it, we can assess what’s worth saving and what should be replaced before drywall goes up.
Signs You Need ADU Right Now
- Your household has outgrown the main house. A parent moving in, an adult child returning, or a growing family all put pressure on a floor plan that worked five years ago. An ADU adds private space and a separate entrance without the cost or disruption of selling and moving.
- You want rental income from property you already own. San Antonio’s rental market is steady, and an ADU turns unused backyard square footage into monthly cash flow. The unit pays for itself over time while increasing resale value on the property.
- You’re caring for aging family members who need proximity, not shared walls. A detached ADU keeps them close enough to check on daily while giving them their own address, kitchen, and bathroom. They keep independence; you keep connection.
- Your property taxes and maintenance costs keep climbing on unused space. A two-car garage that stores lawn tools is expensive storage. Converting it into a rentable or usable unit changes the math on what you’re paying to keep the property.
- Your neighborhood has seen recent ADU permits approved. King William, Mahncke Park, and parts of the near East Side have a rising number of accessory units. When nearby lots add them, your property competes in a different market, and adding a unit sooner locks in contractor pricing and materials before costs move again.
Our ADU Process – Step by Step
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Site walk and honest feasibility conversation. We walk the lot with a laser measure, check zoning on our first visit, and tell you plainly what’s possible and what isn’t. You get a written scope-to-budget estimate within days, not weeks. No obligation beyond the conversation.
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Design and permit package. We draft the plan set, coordinate structural and mechanical specs, and submit to the City of San Antonio. We track every reviewer comment and respond within 48 hours. The permit is the project’s first milestone, and we don’t start any work until it’s in hand.
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Written contract and pricing. Before construction begins, you get a line-item proposal covering every phase, from demo and foundation through interior trim and final inspection. The Garrison Standard means the price goes in writing before any work starts. Change orders, if any, are also in writing before they’re done.
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Construction with structured check-ins. We build to the approved plans and walk you through the site at foundation, framing, and mechanical milestones. The site stays clean at the end of every day, and we use a project calendar so you know when each trade arrives. Uniformed, background-checked crews on every visit.
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Final inspection, close-out, and walkthrough. The city inspector signs off, we remove all construction debris, and we walk the finished unit together. You get a written warranty covering the work for a full year. If anything isn’t right, we return and make it right at no charge.
How Much Does ADU Cost in San Antonio?
ADU costs in San Antonio scale by size, finish level, and whether you’re converting or building new. As a practical range, a garage conversion in a neighborhood like North Central San Antonio runs roughly $60,000 to $120,000 depending on existing slab condition and utility work. A new detached studio of about 400 square feet typically lands between $150,000 and $220,000. A full one-bedroom unit with a kitchen and separate utility hookups runs $200,000 to $300,000 plus site work.
What moves the price: lot access for equipment, soil type and foundation depth, sewer line distance from the main house, HVAC scope, and finish package. A unit with builder-grade materials costs meaningfully less than one with custom cabinetry and stone counters. The best way to avoid overpaying is to fix the scope before you start: know your square footage, your finish level, and your utility setup, then get a line-item quote. Our estimates are free, in writing, and specific to your lot. We don’t do allowances that drift once framing starts.
ADU Near San Antonio – Our Service Area
We serve the full San Antonio metro, including Alamo Heights, Terrell Hills, Olmos Park, Castle Hills, Leon Valley, Converse, and Schertz. Response time for an initial site walk is typically within 3 to 5 business days. If you’re inside Loop 410 or near the Pearl or Southtown, we can often schedule sooner. Not sure if you’re in our area? Call and ask; we’ll tell you straight. For more about what we do across the broader home services family, or to see this page’s local focus, start with ADU in San Antonio.
Serving San Antonio, TX - Our Local Coverage Area
We’re based in the San Antonio area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
Frequently Asked Questions – ADU in San Antonio
An ADU, or accessory dwelling unit, is a secondary housing unit built on a single-family lot. It can be attached to the main house, created from a garage conversion, or built as a detached structure in the backyard. San Antonio’s development code permits ADUs in most residential zones, subject to lot size and setback rules. They’re used for rental income, multigenerational living, or guest space.
Plan on 4 to 8 months from first design conversation to final inspection. Permitting alone usually runs 4 to 10 weeks depending on the city’s current review queue and whether your lot needs zoning variances. Construction moves in stages, and we give you a schedule before we start. Garage conversions trend toward the shorter end; new detached units with foundation and utility work take longer.
A garage conversion typically runs $60,000 to $120,000, a new detached studio around $150,000 to $220,000, and a full one-bedroom unit $200,000 to $300,000. Your price depends on square footage, finish level, foundation work, and utility connections. We provide a written line-item estimate before any work starts. Call (409) 215-3468 to schedule a free site assessment.
Yes. When a garage converts to living space, the existing door either gets replaced with an insulated wall or remains as a functional exterior door, and in both cases we handle the transition correctly. We’re familiar with Amarr, Wayne Dalton, Raynor, and Craftsman hardware, and we know how to air-seal and insulate the opening so the unit passes energy inspection. The door work is scoped into the original proposal, not added later.
ADU construction is planned work, not emergency work, and we don’t sell it that way. But if a weather event damages a partially built unit or a utility issue threatens safety mid-project, our team responds quickly. For active construction sites, we have crews on call for urgent issues. After completion, any covered warranty issue gets scheduled promptly under the 365-Day Done Right Promise.
The Garrison Standard backs the entire project in writing for a full year from final inspection. If workmanship fails in that window, we return and make it right at no charge. Manufacturer warranties on appliances, doors, HVAC equipment, and roofing materials apply separately and are handed to you at close-out. Nothing is verbal; everything is in the contract.
Start by gathering your property survey or site plan, noting where existing utility lines run, and clearing the proposed build area of debris. Think through how you’ll use the unit: rental, family, or home office. That decision drives size, finish level, and which utilities the unit needs. We handle the rest, from permit drawings to final inspection.
Schedule Your ADU Service in San Antonio Today
Ready to see what fits on your lot? Call (409) 215-3468 and schedule a free site walk with our team. You’ll get straight answers on zoning, cost, and timeline, plus a written estimate before anything starts. No pressure, no vague allowances. Just a clear plan for your property in San Antonio, backed by a standard we’ve held since 2010.
Written by Preston Harley, Owner at Garrison Partners, serving San Antonio since 2010.