A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateTrusted Home Addition Contractor for San Antonio Homeowners
Adding square footage to your San Antonio home should not feel like a gamble. Yet too many homeowners get a verbal estimate in March, a different number in June, and no clear answer about when the crew will actually show up. Our team at Benson ADU San Antonio operates differently. Since our roots in the Relay Home Co. family, founded 2006, we have built a reputation around one idea: a written price before work begins and a written guarantee behind every project. No vague promises about “sometime next month.” No change orders that appear out of nowhere after demo day.
If you are researching a Home Addition Contractor in San Antonio, you are probably asking three questions: What will it cost, how long will it take, and will the work hold up. We answer all three in writing. Call (430) 258-2928 and you will reach a live person who can schedule your free estimate and walk you through the entire process before you commit to anything.
Sunroom Addition
A sunroom addition gives you extra living space that feels like part of your San Antonio backyard without the full cost of a foundation-heavy build. It works well for morning coffee, a home office, a plant room, or a reading nook that catches the south Texas light. At Benson ADU San Antonio, sunroom additions typically run from $45,000 to $90,000 depending on size, glazing choices, and whether you want heating and cooling tied into your existing system. The written price we give you before construction starts includes materials, labor, permits, and the 365-Day Done Right Promise, so there are no surprises once the glass goes in.
Glazing and Climate Control
San Antonio summers punish cheap glass. We use energy-efficient glazing packages that keep the room usable from April through October without making your electric bill jump. James Hardie trim and panel options hold up to humidity and UV exposure far better than raw wood, and we will show you samples before you choose.
Foundation and Permitting
A sunroom still needs a proper foundation and city permits, even if it is lighter than a full room addition. Our team handles the permitting paperwork and inspections as part of the fixed price. You will see the permit status in your project tracker, not hear about it after a stop-work order.
Second Story Addition Contractor
A second story addition contractor is the right call when you have maxed out your lot coverage but still need more bedrooms, a primary suite, or a dedicated office. Lifting a roof is a major structural job, and doing it wrong means leaks, sagging floors, and framing that fails inspection. Benson ADU San Antonio manages second story additions from engineering through finish work, with a written price covering every phase. Expect a second story addition in the San Antonio market to run $180,000 to $350,000 depending on square footage, roof complexity, and interior finish level. The first conversation gives you a real number, not a “we’ll see.”
Structural Engineering and Load Path
Adding upward changes how your entire house carries weight. We bring in licensed structural engineers to evaluate the existing foundation and load path before any design is finalized. In San Antonio’s expansive clay soils, that step is not optional. It is the difference between a project that lasts and one that settles within five years.
Living Through the Build
A second story addition is disruptive, but it does not have to be chaotic. We stage the work so your family can stay in the ground floor as long as possible, with sealed-off access points and daily cleanup. You will get photo updates through the project portal so you can see progress without walking the site.
Garage Addition Contractors
Garage addition contractors solve a specific San Antonio problem: older homes built with carports or narrow single-car garages that do not fit two vehicles, a workshop, or secure storage. A garage addition adds secure, enclosed square footage and often does more for resale than a finished room. At Benson ADU San Antonio, attached garage additions usually land between $40,000 and $85,000, with detached builds running a bit higher depending on electrical runs and driveway work. Your written price includes slab, framing, roofing, electrical, and the garage door itself, all backed by our 365-Day Done Right Promise.
Attached vs. Detached Designs
An attached garage is cheaper to heat and easier to access in bad weather, but it also changes your roofline and may complicate setbacks. A detached garage gives you more layout freedom and can double as a workshop without noise bleeding into the house. We walk through both options with real numbers for each configuration.
Electrical and EV Readiness
More San Antonio homeowners are charging electric vehicles, and retrofitting a garage for a Level 2 charger later costs more than planning for it now. We include a dedicated circuit in our garage addition proposals by default. If you want a subpanel for future tools or a home gym, we size the service accordingly.
Bathroom Addition Contractor
A bathroom addition contractor adds comfort and function where your current floor plan falls short, whether that is a second full bath for growing kids or a primary suite bath that does not force a morning line in the hallway. San Antonio homes from the 1960s and 1970s often have one bathroom for three or four bedrooms, and adding one changes daily life more than almost any other upgrade. Expect a full bathroom addition in San Antonio to cost $35,000 to $75,000 depending on plumbing distance from the main stack, fixture choices, and whether you need a new window or venting path. Benson ADU San Antonio gives you a line-item price before you sign, so the tile and the toilet are never a surprise.
Plumbing Runs and Wet Walls
The distance between your new bathroom and the existing drain line drives a big chunk of the budget. A bathroom directly above or beside an existing wet wall is far more affordable than one across the house. We show you the plumbing path on the plan and explain why the price is what it is.
Ventilation and Mold Resistance
San Antonio’s humidity means a bathroom without proper exhaust will grow mold on the ceiling within a year. We install properly sized exhaust fans vented to the exterior, not into the attic, and use moisture-rated drywall as standard. This is the kind of detail that costs a little more upfront and saves thousands in remediation later.
Bedroom Addition Contractor
A bedroom addition contractor helps you stay in a home you love rather than packing up and moving. Maybe you need a first-floor guest room for aging parents, a nursery, or a quiet space for a teenager. A ground-level bedroom addition in San Antonio typically runs $60,000 to $140,000 depending on size, foundation type, and whether you also need a bath. Benson ADU San Antonio prices every bedroom addition with the same written-before-work guarantee: the number we agree on is the number you pay, through the final inspection.
Egress, Light, and Code
A legal bedroom needs proper egress, meaning a window large enough to exit through in an emergency. We handle that code requirement as part of the design, not as a surprise line item later. This matters for resale value and for the safety of whoever sleeps there.
ADU and Multigenerational Options
Some San Antonio families use a bedroom addition as a stepping stone toward a full ADU. If you are adding a suite with a small kitchenette and separate entrance, we can pull from our ADU and room addition experience to design a space that works as guest quarters today and a rental unit later. Ask about home addition layouts that flex over time.
Brands We Service
We build with brands homeowners can research independently, so you are never stuck with a single take-it-or-leave-it product. Boxabl offers factory-built modules that cut weeks off a traditional build timeline, and we handle site prep, foundation, and assembly for these units with the same written-price commitment. Plant Prefab delivers panelized systems with high-efficiency envelopes, and our crews are experienced with their assembly sequences and finishing trades.
Tuff Shed and James Hardie round out our materials toolkit for garage-to-living conversions, accessory structures, and exterior cladding that stands up to Texas sun and humidity. Whether your project leans prefab or site-built, the plan and the price go in writing before we start.
Signs You Need a Pro Right Now
- Your family has outgrown the current floor plan. Kids sharing a room is fine for a while, but when a home office starts doubling as a guest room and a playroom, an addition solves the problem permanently. It is usually cheaper per square foot than selling and buying a larger home in the same San Antonio school district.
- You keep putting off hosting because the house feels tight. Holidays reveal how much space you actually have, and a cramped living room sends guests home early. A sunroom or bump-out addition gives you the gathering space without a full teardown remodel.
- Your garage has become a storage unit, not a garage. When the cars live in the driveway and the garage holds everything else, a dedicated storage addition or a properly sized garage addition fixes the daily frustration. You get your parking back and your tools out of the hallway.
- You are caring for an aging parent or expecting a new family member. A ground-floor bedroom addition with an accessible bath is often far more affordable than assisted living, and it keeps your family together. We design for wider doorways, zero-step entries, and grab-bar blocking from the start.
- Your bathroom situation causes daily stress. One bathroom for four people is not just inconvenient, it is a fight every single morning. A bathroom addition pays for itself in lower stress and better resale, especially in older San Antonio neighborhoods where one-bath floor plans are common.
Our Process, Step by Step
- 1
Free on-site walkthrough and written estimate. We visit your San Antonio property, take measurements, and review your goals. You receive a line-item written price before any commitment is made, no exceptions.
- 2
Design and permit drawings. Our design team produces the drawings your city requires, and we file the permits ourselves. You see the status in your project tracker through every review and approval step.
- 3
Fixed-price contract and material selections. We lock the number from the written estimate into a contract. You choose finishes from vetted options, and we order materials with confirmed lead times so the schedule holds.
- 4
Construction with daily photo updates. Background-checked, uniformed technicians work your job every scheduled day. You get before-and-after photos and a clean site every evening, plus a live person on the phone if you have questions.
- 5
Final walkthrough and written guarantee. We walk the finished addition with you, close out inspections, and hand over the 365-Day Done Right Promise in writing. If something is not right within a full year, we come back and fix it.
How Much Does Home Addition Contractor Cost in San Antonio?
What moves the price most: foundation work, plumbing and electrical distance from existing systems, roof complexity, and finish level. A bathroom addition on an exterior wall with a new sewer line costs more than one beside an existing wet wall. The best way to avoid overpaying is to get a written, line-item estimate that breaks out labor, materials, permits, and contingency. Our free estimates include all of that, plus the written guarantee from Benson ADU San Antonio. Call (430) 258-2928 and you will have a real number in writing, not a range quoted over the phone and changed later.
Our Service Area Near San Antonio
Benson ADU San Antonio serves homeowners across the greater San Antonio metro, including Home Addition Contractor in Schertz, Home Addition Contractor in Live Oak, Leon Valley, Alamo Heights, Windcrest, Bulverde, Converse, Kirby, Castle Hills, Lackland AFB, and Terrell Hills. Typical estimate scheduling runs within a few business days depending on our current workload and your location. If you are inside the loop or in a surrounding suburb, we will tell you straight when we can start and when we can finish.
Serving San Antonio, TX - Our Local Coverage Area
We’re a Home Addition Contractor in San Antonio 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 Home Addition Contractor in San Antonio
What is a home addition contractor?
A home addition contractor plans, permits, and builds new attached or detached living space on your existing property. That includes everything from sunrooms and garage conversions to full second stories and bedroom suites. At Benson ADU San Antonio, the contractor role covers design coordination, structural engineering, permit filing, subcontractor management, and the finish work, all under one written price and one written guarantee.
How long does a home addition take in San Antonio?
A typical bedroom or bathroom addition runs 8 to 14 weeks from permit approval to final inspection, while a second story can take 5 to 8 months. Prefab options like Boxabl or Plant Prefab modules can shorten the on-site build significantly, sometimes by several weeks. Your written estimate includes a schedule with milestone dates, and we update it in real time through the project portal if weather or inspections shift things.
How much does a home addition cost in San Antonio?
Plan on $40,000 to $350,000 depending on scope, with most single-room additions landing between $60,000 and $140,000. Sunrooms run $45,000 to $90,000, garage additions $40,000 to $85,000, and bathroom additions $35,000 to $75,000. Every Benson ADU San Antonio project gets a written, line-item price before work starts, so the number on your estimate is the number on your final invoice.
Do you work with prefab and panelized home addition brands?
Yes. We are authorized to build with industry-leading prefab and materials brands including Boxabl, Plant Prefab, Tuff Shed, and James Hardie. That gives you curated product options instead of one take-it-or-leave-it package. We walk you through the tradeoffs of each brand for your specific site and goals before you choose.
Are you available for urgent home addition issues?
For structural emergencies like a failing foundation under an existing addition or storm damage to a sunroom, we prioritize calls from existing customers first. A live person answers the phone around the clock, every day of the year, so you will never leave a voicemail and wait until Monday. We do not promise same-day construction starts, but we will give you an honest assessment of when work can begin.
What warranty does Benson ADU San Antonio provide?
Every project carries the 365-Day Done Right Promise in writing. If the work is not right within a full year, we make it right. That includes a free second visit if any covered repair fails. The guarantee is stamped on your project documents before construction starts, not buried in fine print after the fact.
How should I prepare for a home addition estimate?
Gather any property surveys, HOA guidelines, and a rough idea of square footage you want. Think about whether you need a bathroom included, a separate entrance, or a future rental setup. We handle the rest at the on-site walkthrough, and you will leave with clear next steps and a written number to consider.
Schedule Your Home Addition Contractor Service in San Antonio Today
Ready to get a written price for your home addition? Call (430) 258-2928 to schedule a free on-site estimate with Benson ADU San Antonio. You will get a real number, a clear timeline, and a written guarantee before any work begins. If you are still exploring options, give us a call anyway. A live person answers and will walk you through costs, brands, and the process plainly.
Written by Troy Eastman, Owner at Benson ADU San Antonio, serving San Antonio homeowners with written-price home additions and ADUs since 2006.
