Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
After
Before
After
Before
AfterFast, Reliable Home Additions & ADU Across Schertz
A room addition or detached ADU in Schertz typically runs $45,000 to $130,000 for a standard build, and a full new ADU falls in the $90,000 to $220,000 range depending on size, slab work, and finishes. We get calls from homeowners throughout 78154 who want to know whether their lot can even support a second structure or a bump-out, and the honest answer usually comes down to two things: the clay under your slab and the wind load your roofline has to carry. Call (877) 610-1318 and we’ll come out, walk the property, and tell you what’s actually possible before you spend a dime on plans.
Tom Barrett and his sons run our Home Additions & ADU team, and we live close enough to Schertz that we’re on your street most weeks. We’ve worked in Fossil Creek, The Crossvine, Sedona, and Carolina Crossing. Our Schertz customers get the same thing every other customer gets since 1998: a written scope, permits pulled, and a price that doesn’t move unless it moves on paper with your signature on it.
Why Barrett & Sons Construction Is Schertz’s Preferred Home Additions & ADU Company
People in Schertz don’t want a franchise sending strangers from two counties over. They want a name they can find at the hardware store on a Saturday. Tom Barrett publishes his name, his address, and his license number. Look it up before you sign anything. That’s the whole point.
Our crews have been in and out of Schertz subdivisions long enough to know what the original builder left behind. On a room addition in Fossil Creek, our crew found the builder’s perimeter grading had settled toward the slab in under twelve years, feeding rainwater under the post-tension foundation during fall storms. We re-graded the perimeter, added a French drain before tying the new footing into the existing slab, and specified a storm-rated window package to carry the required wind load. The addition passed inspection sign-off with a letter documenting drainage and wind-load compliance for the homeowner’s insurer. That’s the difference between a quote that looks cheap and a job that actually closes out.
Every addition and ADU we build in Schertz comes with a written 90-Day Done Right Promise on the contract. Not buried in fine print. If it’s not done right, Tom comes back and makes it right, one call.
Our Home Additions & ADU Services in Schertz
ADU Design & Permitting
Before you pour a dollar into concrete, the design has to answer for the Blackland Prairie clay under your lot. A detached ADU in Schertz needs a foundation detail that accounts for shrink-swell movement, and the permit package has to show the load path from roof to footing, not just a nice floor plan. We handle the drawings, the permit submittal, and the inspections, and we’ll tell you when the city wants a third-party geotech report before they’ll even look at the plans.
New Detached ADU
A new detached ADU in Schertz runs $90,000 to $220,000 all-in. That range swings on square footage, utility trenching distance, and whether your lot’s existing drainage already flows away from the foundation or toward it. On the east and north sides of Schertz, we routinely find builder grading that settled the wrong way within a decade, which means drainage re-grading and a French drain become part of the scope before the first footing goes in.
Garage Conversion ADU
Converting an attached garage in Schertz runs $30,000 to $80,000, and the real question is almost never the framing. It’s the slab. Garage slabs here are typically poured with less steel and a thinner cross-section than the house slab, and when you tie living space onto it, the clay’s seasonal movement shows up at the threshold and the door frames. We spec the connection so the new space can move with the garage slab instead of fighting it, and we document it for the inspector.
Junior ADU & Interior Conversion
A junior ADU inside your existing Schertz home’s footprint is the most straightforward way to add a rental unit or an in-law suite without fighting the soil at all. The slab’s already there. The roof’s already there. The work becomes about egress windows, a kitchenette, a separate entrance, and separating the HVAC. And unlike a detached build, an interior conversion rarely triggers new drainage requirements from the city, because you’re not adding roof area or impervious cover.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Schertz
When we tie a new roofline or hardscape onto a Schertz home, we use materials you can look up. Belgard and Techo-Bloc for pavers and site walls, because a patio or walkway that butts against a new addition has to handle the same clay movement as the foundation it sits on. Quikrete products for the concrete work, whether it’s a thickened-edge slab under an ADU or re-grading the perimeter of a room addition. We stock what Schertz jobs actually need, and if a brand’s spec sheet is what the inspector wants to see, we’ve got it on file before we start.
Common Home Additions & ADU Problems We See in Schertz Homes
- Post-tension slabs tied to new footings without a slip joint. A new footing that bonds rigidly to the existing slab can crack within two seasonal shrink-swell cycles. We detail the connection so the addition moves independently where it has to.
- Garage conversions with wall ties and roof straps not listed for the wind-load requirement. The rough-in passes, the final fails when the inspector checks the load path. We spec the hardware before the drywall goes up.
- Additions that reuse the original builder’s roof drainage. If the builder’s grading settled toward the slab (and in Schertz it often has), the new roof area just adds more water to a drainage path that already runs the wrong way. We re-grade and add French drains as standard scope.
- Thermal expansion gaps ignored on metal and masonry assemblies. Schertz summers routinely pass 100°F, and the gap you didn’t leave in April is a buckle or a crack by August. We cut and detail flashings for the full seasonal range, not the day we installed it.
Pricing for Home Additions & ADU in Schertz, TX
A home addition in Schertz runs $45,000 to $130,000. A detached ADU runs $90,000 to $220,000. A garage conversion runs $30,000 to $80,000. Those ranges are real, and they include the things a low-ball quote leaves out: the drainage re-grade, the wind-load-rated ties and straps, the permit fees, the inspection sign-off, and the letter your insurer will ask for. Call (877) 610-1318 for a free estimate and we’ll put the scope in writing before you commit to anything.
| Project Type | Typical Schertz Range |
|---|---|
| Home Addition (room bump-out or second story) | $45,000-$130,000 |
| Detached ADU (new build) | $90,000-$220,000 |
| Garage Conversion ADU | $30,000-$80,000 |
What moves the number inside those ranges? Lot access for concrete trucks, how far utilities have to run from the meter, whether your existing drainage already flows away from the foundation, and whether the city wants a geotech report before permit issuance. We also carry a permanent 10% Senior & Veteran discount, and the written quote you get is the price we build to. No change order happens without your signature.
We Also Serve Cities Near Schertz
We work throughout the Schertz-Cibolo-Converse area, and our crews are regularly in Selma, Universal City, Cibolo, and Converse. Dispatch and scheduling run through our San Antonio office, but the crew you meet on the first day is the crew you’ll see for the whole job. If you’re in Schertz or any of the surrounding communities, call (877) 610-1318 for a free estimate.
Serving Schertz, TX - Our Local Coverage Area
We’re based in the Schertz 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 - Home Additions & ADU in Schertz
Schertz additions and ADUs must be designed to a 115-mph basic wind speed under the current Texas-adopted building code, which translates to specific uplift ratings on truss ties, wall straps, and roof-to-wall connections. The inspector will check the load path, not just the finished look. A compliant quote includes the listed hardware and the truss engineering to match; a low-ball quote usually plans to swap it in only if the inspector catches it. Call (877) 610-1318 for a free estimate and we’ll show you the spec sheets for exactly what your job needs.
After a storm event, an insurer will ask for evidence that the structure was built to the code that was in effect when the permit was issued. A compliant Schertz addition comes with a signed inspection record and, if you ask for it, a letter documenting the wind-load path and the drainage re-grade. Without that paper, a claim can drag out or get denied on the basis of original construction quality. We document what we built and we hand you the file.
Because the original builder grading in many Schertz subdivisions settles toward the foundation within the first decade, feeding rainwater under the slab and making clay heave worse. The drainage re-grade and French drain are not optional add-ons; they’re the difference between an addition that stays square and one that starts binding doors by the second wet season. If a bid doesn’t mention drainage, ask why.
Sometimes, yes. If the garage slab is thick enough and has enough steel for the new occupancy classification, you can convert it without tearing out concrete. But many Schertz garage slabs are poured thinner than the house slab, and the inspector will want to see the original pour details before they sign off. We verify the slab before you spend money on design, and if it won’t pass, we tell you on the front end. Call (877) 610-1318 to schedule a free estimate and we’ll check yours.
A compliant quote includes the drainage re-grade, listed wind-load hardware, the permit fee, the inspection sign-off, the geotech report if the city requires it, and a written scope that doesn’t move without a written change order. A low-ball quote includes framing, drywall, and a promise. Then the change orders start. That’s the bill you never saw coming. Get the scope in writing from us before you sign anything.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Schertz and surrounding Texas communities since 1998.