A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Room Addition Contractor Across San Antonio
Room additions in San Antonio run from roughly $165 to $310 per square foot, depending on foundation type, finishes, and what the walls reveal once opened. That range covers everything from a simple bump-out bedroom to a full primary suite with a bathroom. Benson ADU San Antonio starts every room addition with a written inspection, a written price, and the 365-Day Done Right Promise, so the number you approve is the number you pay. Call (430) 258-2928 for a free estimate and a plan that accounts for San Antonio’s older homes before demo day, not after.
Why Benson ADU San Antonio Is San Antonio’s Preferred Room Addition Contractor Company
We’ve built our reputation across San Antonio by treating old houses with the respect they demand. Homeowners in Alamo Heights, Terrell Hills, and the Dominion call us because we name the hard realities up front, then solve them. Our background-checked, uniformed technicians arrive with a live arrival time, and every project gets photo documentation and daily logs through The Relay Visibility Guarantee.
What separates us from other Room Addition Contractor teams in San Antonio is how we handle the unknown. When we open a wall and find knob-and-tube wiring, termite damage, or a foundation issue, we don’t panic and we don’t pad the bill. We scope it, photograph it, write a signed change order, and proceed only after you approve the number. Troy Eastman, who leads our San Antonio crews, insists on that discipline because it protects both sides.
San Antonio homeowners consistently tell us the same thing: the written price, the live person on the phone, and the fact that every line item gets put in writing before work starts is why they recommend us to neighbors.
Modular Home Addition in San Antonio
Modular Home Addition in San Antonio is the fastest route to a full-size new room without months of open framing on your lot. The wall, floor, and roof panels are precision-built offsite, often using James Hardie cladding and engineered framing, then delivered and set on your prepared foundation. For San Antonio’s sprawling suburban lots in areas like Stone Oak or Alamo Ranch, a modular addition can cut site time by 30 to 40 percent compared to conventional framing.
Prefab Panels and San Antonio’s Climate
San Antonio’s heat and humidity mean panel seams, flashing, and vapor barriers have to be right the first time. We spec materials rated for sustained moisture and UV exposure, and we match the existing roofline so the addition sheds water like the original structure. A modular room addition in San Antonio typically runs $185 to $295 per square foot, complete with drywall, paint, and tie-in to existing systems.
When Modular Beats Site-Built
If you’re adding a bedroom over a tight backyard with limited access, modular panels can be set with a small crane in a single day. That matters in San Antonio’s older neighborhoods, where alleys and mature oak trees make conventional material delivery a headache. We regularly build modular additions in Terrell Hills and Olmos Park where the lot leaves no room for staging lumber piles.
Home Addition Plans in San Antonio
Home Addition Plans in San Antonio have to account for more than square footage. The city’s building codes, setback requirements, and historic district overlays all shape what you can build and where. In the King William Historic District, for example, any visible addition must complement the original architecture, which changes material choices and rooflines from day one. We prepare plans that pass COSA review the first time.
Engineering for Clay Soil
San Antonio’s expansive clay soil moves with moisture cycles. A plan that ignores soil movement risks cracks at the connection joint between old slab and new within the first twelve months. Our Home Addition Plans include soil analysis and, where needed, engineered piers or deepened footings so the addition doesn’t pull away from the house.
Planning Around What’s Already There
Every plan we draw begins with a structural inspection of the existing home. In a 1950s ranch in Monte Vista, that means checking joist spans, electrical panel capacity, and HVAC sizing before we ever draw a wall. The plan then includes realistic allowances for upgrades a permit will trigger, so your final price matches the plan, not a string of surprises. Call (430) 258-2928 and we’ll walk the property, measure, and start the written plan.
Trusted Brands We Service in San Antonio
We build room additions with materials San Antonio homeowners can research on their own. That includes panelized systems from Abodu and Cover, engineered framing for custom layouts, and James Hardie siding and trim that stands up to San Antonio’s hail season and humidity. Tuff Shed structures work well for detached home offices or workshop additions that don’t need full residential finishes. Because we’re authorized to source from these brands, we keep lead times predictable and get materials to San Antonio job sites faster than one-off custom ordering.
Common Room Addition Contractor Problems We See in San Antonio Homes
- Pier-and-beam settling in Lavaca and King William. Original foundations from the 1920s and 1930s have often settled unevenly. We level and add moisture barriers before any framing, and the cost goes into the written estimate, not a post-demo phone call.
- Knob-and-tube wiring behind plaster walls. Opening a wall on a 1940s bungalow in Beacon Hill or Monte Vista frequently uncovers live knob-and-tube. We pull the electrical permit, upgrade to code, and write every change order before touching a wire.
- Termite damage in rim joists and sill plates. San Antonio’s warm climate keeps termites active year-round. On a recent Beacon Hill project, we replaced a compromised rim joist and documented each step with photos and a signed scope adjustment.
- Undersized HVAC for the new square footage. Many mid-century San Antonio homes have systems sized for the original footprint. A room addition triggers a load calculation, and we include any duct or condenser upgrades in the written plan so the new room actually cools in August.
Pricing for Room Addition Contractor in San Antonio, TX
A room addition in San Antonio generally costs between $165 and $310 per square foot. A 200-square-foot home office addition often lands between $33,000 and $62,000, while a 400-square-foot primary suite with bathroom may run $66,000 to $124,000. Foundation type moves the number fast: a simple slab-on-grade addition in a newer subdivision costs less than releveling and building over an original pier-and-beam system in Lavaca or King William.
What most moves the final figure is what the walls hide. Knob-and-tube replacement, service panel upgrades, termite repairs, and HVAC resizing are the common San Antonio surprises. We quote them as written allowances, then confirm exact costs with a signed change order before proceeding. You’ll never get a verbal estimate that shifts at the door. Call (430) 258-2928 for a written, line-item price.
We Also Serve Cities Near San Antonio
Benson ADU San Antonio handles room additions throughout the metro, including Converse, Universal City, Schertz, and Bulverde. If you’re in one of those communities, the same written price, 365-Day Done Right Promise, and background-checked crews apply. See our Room Addition Contractor in San Antonio service area for full coverage details.
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.
FAQs About Room Addition Contractor in San Antonio
We stop work, photograph the wiring, show you exactly what we found, and pull the electrical permit the same week. The repair is written as a line-item change order with a specific price, and you approve it before we proceed. On a recent 1940s Beacon Hill bungalow, this added about $4,800 to the project for full replacement and a panel upgrade, and the owner saw every receipt. Call (430) 258-2928 and we’ll explain what your home’s age makes likely before we open a single wall.
In most cases, San Antonio’s permit review requires bringing the affected electrical circuits, smoke detectors, and often the service panel up to current code. If your 1950s Monte Vista home has an original 100-amp panel, the addition likely triggers a 200-amp upgrade. We include that cost in the written allowance from the start, so the permit isn’t a financial ambush.
Yes, and we do it regularly. The process starts with leveling the existing foundation, repairing or replacing damaged piers, and installing a moisture barrier beneath the crawl space. Depending on how far the original structure has settled, this typically adds $4,000 to $9,000 to the project in Lavaca’s older homes. We write that cost into the estimate before construction starts, not after the framing is up.
We spec impact-rated roofing, UV-stable siding like James Hardie fiber cement, and high-efficiency HVAC sized for San Antonio’s summer loads. Hail season from March through June means we avoid thin-gauge metal panels and cheap sealants. The material upgrade adds roughly 5 to 8 percent to the total cost, and it’s the difference between an addition that looks right for five years and one that holds up for thirty.
We contain the area, document the damage with photos, bring in a licensed termite treatment if active infestation is present, and replace the compromised framing. The repair is scoped and priced as a written change order before we proceed. On a 1940s Beacon Hill bungalow, we replaced a rim joist, upgraded the service panel, and logged every step with daily photos so the owner saw exactly what the final invoice covered. Call (430) 258-2928 for a free estimate that accounts for what San Antonio’s climate and soil actually do to old framing.
Adding a room to your San Antonio home means opening walls and finding what’s really there. Benson ADU San Antonio plans for it in writing from the first conversation. Call (430) 258-2928 today for a free, written estimate and the 365-Day Done Right Promise on every project.
Written by Troy Eastman, Owner at Benson ADU San Antonio, serving San Antonio and surrounding communities.
