A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateTrusted ADU Builders for San Antonio Homeowners
Adding an accessory dwelling unit in San Antonio typically costs between $180,000 and $380,000 for a turnkey build, and the smartest first step is getting a written price before anyone swings a hammer. Benson ADU San Antonio has been part of the Relay Home Co. family since 2006, building backyard units, garage conversions, and attached additions with one promise that separates us from the pack: the price we put in writing is the price you pay. No change orders at the door, no vague verbal estimates. Troy Eastman and our team serve ADU builders in San Antonio with honest numbers, real timelines, and a 365-Day Done Right Promise stamped on every contract. Call (430) 258-2928 to talk plans and pricing.
ADU Construction
ADU Construction is the full build-out of a secondary dwelling unit on your existing property, covering everything from foundation to finish work. It’s the right choice when you have a yard or garage that can support a separate living space and you want a finished unit that adds rental income, houses family, or becomes a dedicated home office. Benson ADU San Antonio handles the entire ADU Construction process under one roof, with a written price range of $180,000 to $380,000 depending on size, site conditions, and the prefab system you choose. We pull permits, manage inspections, and keep you updated with photos and a live timeline through the Relay Visibility Guarantee.
Foundation and Utility Coordination
A properly built ADU starts below ground. We evaluate soil, set the foundation type (slab, pier, or prefab panel base), and coordinate water, sewer, and power connections with the utility district before framing begins. This is where a lot of unqualified builders lose time and money, and why our written quote includes utility coordination up front.
Turnkey Interior and Exterior Finish
Once the structure is up, we handle insulation, drywall, flooring, kitchen and bath build-out, and exterior cladding, including James Hardie siding when specified. Your project doesn’t bounce between subs you have to chase. One team, one schedule, one written guarantee that any issue discovered within 365 days gets corrected at no charge, as detailed in our ADU Builders Maintenance Checklist for San Antonio Homeowners.
Detached ADU
A Detached ADU is a standalone living unit built entirely separate from the main house, typically 400 to 1,200 square feet and positioned in the rear or side yard. This is the option when you want true privacy from the primary residence, whether for a tenant, an aging parent, or a workspace that needs a door that closes against the noise of the main house. In San Antonio, a Detached ADU from Benson ADU San Antonio generally runs $200,000 to $380,000 because it requires its own foundation, utility trenching, and often a longer run from the street. Prefab options like Plant Prefab and Boxabl can reduce build time significantly compared to site-built framing.
Site Layout and Setback Planning
Setbacks are the required distances between your structure and property lines, and they vary by lot type and zoning district. We measure, map, and confirm setbacks before we ever quote your Detached ADU, so the written price reflects the actual buildable footprint, not a guess. If the lot is tight, we will tell you what fits and what doesn’t, in plain terms.
Prefab Panel Delivery and Assembly
When speed matters, we spec prefab panel systems that arrive on a flatbed and assemble in weeks, not months. Plant Prefab and Boxabl units come with factory-controlled precision, which reduces the variables that typically cause cost overruns on a site-built Detached ADU. You still get the same 365-Day Done Right Promise on the final product.
JADU
A JADU, or Junior Accessory Dwelling Unit, is a smaller living space created within the footprint of the existing home, typically a converted garage, basement, or a converted portion of the house with its own entrance and efficiency kitchen. JADUs are capped at about 500 square feet and are ideal for a single occupant, a home office, or a modest rental that keeps construction costs down. In San Antonio, a JADU conversion usually lands between $80,000 and $150,000 depending on the existing structure’s condition and the level of finish you want. Benson ADU San Antonio handles the permit, structural upgrades, and finish work on JADUs, with the same written pricing guarantee as any larger project.
Garage Conversion Feasibility
Not every garage can legally become a JADU. We check ceiling height, foundation condition, ventilation, and access to determine whether your structure can be converted, what it will take, and what it will cost. If the garage isn’t viable, we will say so before you spend money on plans.
Efficiency Kitchen and Separate Entrance
A JADU requires a kitchenette, a separate entrance, and a bathroom of some kind. We design and build these within the existing footprint while keeping the main house livable during construction. The result is a compact, rentable unit that shares utility lines with the main property, keeping connection costs lower than a Detached ADU.
ADU Plans
ADU Plans are the architectural drawings, structural calculations, and permit-ready documents required before any accessory dwelling unit can be built in San Antonio. You need them when you are serious about building, because the city will not issue a permit without a stamped set that shows setbacks, electrical layout, foundation details, and compliance with local building codes. Benson ADU San Antonio produces ADU Plans in-house or through our licensed design partners, typically costing $5,000 to $15,000 depending on project complexity, and we fold that cost into your written build quote when we handle the full project. You see the drawings before you sign anything.
Permit-Ready Documents
Our ADU Plans are prepared to the standard the permitting office expects: title sheet, site plan, floor plan, elevations, sections, and structural notes. We submit on your behalf, track the review, and handle revision requests. The plan set becomes the fixed document that governs the build, which is why our written price holds from start to finish.
Pre-Approved Plan Sets
If you are working with brands like Plant Prefab or Tuff Shed, some of their models include pre-engineered plan sets that can speed the permitting timeline. We know which systems qualify, what the Texas code amendments require, and how to adapt a pre-approved design to your lot. You get a faster start without paying for a fully custom drawing package.
ADU Contractor
An ADU Contractor is the licensed general contractor who manages the build from permit to final inspection, coordinating subcontractors, scheduling inspections, and remaining accountable for the completed structure. You need one the moment you have a plan set and want the project built correctly the first time. Benson ADU San Antonio operates as a full-service ADU Contractor across the San Antonio region, with project costs typically between $180,000 and $380,000 for a complete unit, and a written price before any work begins. Troy Eastman oversees every job, and our background-checked, uniformed technicians handle the on-site work.
Single Point of Accountability
When you hire Benson ADU San Antonio as your ADU Contractor, you do not become a project manager for five different crews. We manage structural, electrical, plumbing, drywall, paint, and finish under one contract and one schedule. If something is wrong within 365 days of completion, the same team fixes it.
Transparent Billing and Photo Updates
You will get a digital invoice payable by link, real-time progress photos, and no surprises at the end of the month. Our written price eliminates change orders that appear after the fact on most other job sites. This is the Relay Visibility Guarantee in practice: you always know what is happening and what it costs.
ADU Design
ADU Design is the process of shaping the size, layout, materials, and exterior style of your accessory dwelling unit before plans are drawn and permits are pulled. It is the stage where you decide whether the unit becomes a studio, a one-bedroom, or a two-bedroom, and what it will look like from the backyard. Benson ADU San Antonio provides ADU Design guidance as part of every project, with design fees usually running $3,000 to $10,000 depending on complexity, and those fees credited toward the total build when you move forward with us. You get design options, not a single take-it-or-leave-it layout.
Prefab Product Selection
Our access to leading prefab brands like Abodu, Dvele, Mighty Buildings, and Plant Prefab means your ADU Design can start from a proven platform rather than a blank page. We walk you through the tradeoffs of each system: cost, lead time, ceiling height, and finish options. You choose based on real numbers and real product specs, not a sales pitch.
Exterior Finish and Curb Appeal
A backyard unit should look like it belongs on the property, not like a shed with drywall. We detail exterior cladding, window placement, door styles, and rooflines, including James Hardie products where durability matters most. The finished unit adds rental appeal and property value, and the design process is where that value gets locked in.
Backyard ADU
A Backyard ADU is any accessory dwelling unit situated in the rear yard, whether site-built or prefab, and it is the most common approach for San Antonio lots with usable rear space. Homeowners choose a Backyard ADU when they want to keep the main house unchanged while still adding a rentable unit, a private guest suite, or a quiet studio. Benson ADU San Antonio builds backyard units from $200,000 to $380,000, and we handle the site prep, utility runs, structure, and finish. If your yard has access for a construction crew and space to meet setbacks, a Backyard ADU is likely feasible.
Site Preparation and Access
The first thing we check is whether we can get machinery and materials to the build site without tearing up your landscaping or your neighbor’s fence. Rear yards in older neighborhoods can be tight, and that changes the build approach. We plan the access route before we quote, so the price includes what the job actually needs.
Built-In Storage or Tuff Shed Integration
Some homeowners start with a Tuff Shed shell and want it finished into a conditioned living space. While not every shed can be legally converted, we do build Tuff Shed structures where the model and local code allow, and we can integrate built-in storage into the design of any Backyard ADU. The finished product is a real living unit, not a glorified tool shed.
Brands We Service
Benson ADU San Antonio is authorized to build with some of the most respected prefab ADU systems in the country, including Plant Prefab and Boxabl. Plant Prefab units are built to near-custom standards in a factory and shipped as panels or modules, which cuts on-site construction time and gives you a tighter build envelope than most site-built frames. We know their structural details, their electrical rough-in points, and their lead times well enough to give you a real completion date.
Boxabl is a different animal: a foldable module that ships on a standard trailer and unfolds on site, which can work on lots where a wide-load delivery would be impossible. We have built Boxabl units and know how to prep the foundation, set the modules, and connect utilities correctly. Whatever brand you are comparing, whether it’s one of these or a James Hardie-clad site build, we can spec it, price it, and stand behind it for 365 days. ADU builders in Schertz and the surrounding area work with the same product lines.
Signs You Need a Pro Right Now
- Your written quote keeps shifting. If a contractor will not put a fixed price in writing before the first day of work, you are going to get squeezed mid-project. A pro issues a written price and honors it. Benson ADU San Antonio does exactly that on every job, no exceptions.
- Your lot has drainage or slope problems. San Antonio soil shifts, and a poorly sited ADU will crack or hold water. We evaluate site drainage and foundation requirements before we quote, so the build starts on stable ground and the price accounts for it.
- You are not sure if your project is even legal. Setback violations, unpermitted conversions, and wrong occupancy designations can bite you when you sell or when the city comes looking. We confirm zoning and code compliance before drawing a single line.
- You want a specific prefab brand. Not every contractor can build a Plant Prefab or Boxabl unit correctly. We are authorized to build with these systems and have the trained crews to handle factory-built components properly.
- You need this done on a timeline. An ADU project that drags on for a year costs you rent, family stress, or both. Our written schedule and real-time progress tracking mean you see the pace and know the finish date from the start.
Our Process, Step by Step
- 1
Site assessment and written estimate. We walk the property, measure the buildable area, check access, and review utility locations. Within days, you get a written price with line items, not a ballpark figure delivered over the phone.
- 2
Design and plan approval. We create or adapt a design, present the plans, and revise until you are happy. The plan set is submitted for permits, and we track the review so nothing stalls in a queue without you knowing why.
- 3
Foundation and utility rough-in. We prepare the site, pour the foundation or set the prefab base, and run water, sewer, and power lines to the unit. Progress photos are shared at every stage through our digital project tracking.
- 4
Structure, systems, and finish. The walls go up, the roof goes on, and the electrical, plumbing, and HVAC are installed. We then finish the interior and exterior, including cladding and paint, with inspections scheduled and passed along the way.
- 5
Final walkthrough and 365-Day Done Right handoff. We walk the finished unit with you, item by item, and address any punch-list items before we call the job complete. From that day forward, the 365-Day Done Right Promise applies, in writing, on paper you keep.
How Much Does ADU Builders Cost in San Antonio?
A typical detached ADU in San Antonio runs $200,000 to $380,000 for a complete unit with kitchen, bath, and utilities connected. A JADU conversion inside the existing home footprint usually lands between $80,000 and $150,000. A fully customized, larger unit with high-end finish work can push toward $400,000 or more. What affects the price most: whether the unit is site-built or prefab, how far the utility connections run, the foundation type your soil requires, and the finish level inside. You avoid overpaying by getting three things in writing before you start: the full scope of work, the fixed price, and the completion timeline. Our free estimate includes a line-item breakdown of every major cost category so you can compare apples to apples rather than vague totals. Call (430) 258-2928 for an exact quote, and remember: the price we quote is the price you pay. No change orders, no surprises.
Our Service Area Near San Antonio
Benson ADU San Antonio serves homeowners across the greater San Antonio area, including ADU builders in Live Oak, Schertz, Leon Valley, Alamo Heights, Windcrest, Bulverde, Converse, Kirby, Castle Hills, Lackland AFB, and Terrell Hills. Most site assessments are scheduled within a few business days, and our written estimates are delivered as soon as the measurements and scope are confirmed. If you are anywhere in the metro, chances are we are already working nearby.
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 About ADU Builders in San Antonio
An ADU builder in Converse and surrounding areas is a general contractor who specializes in accessory dwelling units: detached backyard units, garage conversions, JADUs, and attached additions. Benson ADU San Antonio handles the full process from plans and permits to final inspection, with a written price before any work starts. Troy Eastman and our crews are experienced with both site-built and prefab construction methods.
Most ADU projects take between five and ten months from the first design meeting to final inspection. Prefab systems like Plant Prefab and Boxabl can reduce on-site construction time by several weeks. Permitting, utility coordination, and weather window all play a role, and your written timeline is part of the quote. Call (430) 258-2928 to discuss a realistic schedule for your specific lot.
A complete detached ADU typically costs $200,000 to $380,000, while a JADU conversion runs $80,000 to $150,000. The range depends on size, site conditions, finish level, and whether you choose a prefab system or site-built framing. Every Benson quote includes a line-item breakdown so you see exactly where the money goes before you commit.
Yes. We are authorized to build with Boxabl, Plant Prefab, and other leading prefab systems, and we regularly spec James Hardie cladding for exterior finishes. If you have a specific brand in mind, we will review the product specs with you and confirm whether it fits your lot, budget, and timeline before you buy anything.
We cannot start a permitted ADU build the same day, and no reputable contractor can. What we can do is move quickly on the front end: site assessment, written estimate, and plan review are scheduled promptly. Our 24/7 phone support at (430) 258-2928 means a live person answers when you have questions, even on weekends.
Every Benson ADU San Antonio project includes the 365-Day Done Right Promise in writing. If any covered work fails within one year of completion, we return and make it right at no charge to you. You also receive a free second visit if any covered repair fails, with no fine print and no deductible.
Start by gathering your property survey or plot plan, noting where your utility meters are located, and thinking about what the unit is for: rental income, family housing, or a workspace. Clear access to the rear yard helps us assess feasibility faster. Beyond that, just call (430) 258-2928 and we will handle the rest, from measurement to written price.
Schedule Your ADU Builders Service in San Antonio Today
Ready to see what an ADU will cost on your property? Call (430) 258-2928 to schedule your free estimate with Benson ADU San Antonio. You will get a written price, a straightforward timeline, and a 365-day guarantee on every part of the build. No pressure, no verbal estimates, no fine print.
Written by Troy Eastman, Owner at Benson ADU San Antonio, serving San Antonio since 2006.
