Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterFast, Reliable Home Additions & ADU Across Kirby
Bathroom Remodeling in Kirby, home additions and ADU construction in Kirby, TX typically runs $45,000 to $130,000 for a room addition and $90,000 to $220,000 for a new detached ADU. The biggest variable isn’t lumber or drywall. It’s what we find when the walls come open in a 1950s or 60s slab ranch, and whether your contractor knows Kirby’s own permitting system well enough to keep the job moving. Our crews work Kirby’s 78244 neighborhoods every week, and we know what Kirby City Hall expects before we pull the first permit. Call (877) 610-1318 and we’ll walk the job with you, no charge for the first visit inside the county.
Why Barrett & Sons Construction Is Kirby’s Preferred Home Additions & ADU Company
Tom Barrett founded this company in 1998 and his sons run the crews. That matters in a town like Kirby, where a contractor’s reputation follows him to the gas station and the school pickup line. Kirby homeowners have watched too many San Antonio outfits quote one number on the phone and show up with another. Our answer is simple: every scope, every allowance, every price change arrives as a written change order before a single nail moves. The allowance that isn’t on paper is a surprise waiting for a date.
We also know something most out-of-area contractors don’t. Kirby is a fully independent municipality completely encircled by San Antonio. Every Home Addition or ADU permit runs through Kirby City Hall’s own inspections and code enforcement, not San Antonio’s system. That distinction reshapes project timelines, and we plan for it from day one. Crew members who carry the Barrett & Sons name are background-checked, uniformed, and familiar with Kirby’s inspection process. A live person answers the phone 24 hours a day, seven days a week, not a voicemail box and not an out-of-state call center.
Our Home Additions & ADU Services in Kirby
Here’s what we handle most often in Kirby’s 78244 ZIP, where the housing stock runs heavily to post-WWII ranch homes on slab foundations. If you’re considering Home Additions & ADU work anywhere in Kirby, these are the jobs we know best.
ADU Design & Permitting
Before we draw anything, we sit down with you and walk the property. Kirby’s city offices run their own plan review and code enforcement on a smaller-office timeline, so we budget for that reality. We handle the drawings, the structural calculations, and the permit package, then coordinate with Kirby’s inspector at every stage. You don’t chase paperwork. We do.
Garage Conversion ADU
On a 1960s ranch off Ackerman Road in Kirby’s 78244, our crew opened a load-bearing wall for a room addition and found aluminum wiring feeding the original panel, plus a rotted sill plate from decades of slab movement on expansive clay. We stopped work, wrote the scope of work and allowances into the contract as a change order, coordinated with Kirby’s inspector before covering the rough-in, and replaced the affected framing before inspection sign-off. That’s what a garage conversion in Kirby actually involves. Older homes hide things, and we plan for them.
New Detached ADU
Kirby sits on the eastern Bexar County expansive black-clay soil belt. That soil heaves and settles with every wet-dry cycle, and a detached ADU foundation has to be engineered for it. We don’t pour a slab and hope. We size the footings, plan the drainage, and coordinate the soil and foundation inspections Kirby requires. A new ADU should stand square for decades, not crack within two seasons.
Junior ADU & Interior Conversion
Many Kirby ranch homes have a den, a formal dining room, or a utility room that can convert into a junior ADU without a full separate entrance, depending on what Kirby’s current code says. These jobs move faster than a detached build, but they still trigger electrical, plumbing, and egress upgrades when walls come open. We write those allowances into the contract up front so you’re not surprised at the final invoice.
Room Additions & Second Stories
A room addition over a 1960s slab means verifying load-bearing capacity before we frame anything. Kirby’s inspector will fail a rough-in if the foundation math doesn’t work, and that’s a good thing. The permit inspector works for you, not for me. That’s why I like him. We do the structural review before the first board goes up, so the inspection is a sign-off, not a stop-work order.
What happens when you call
- 1
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.
Trusted Brands We Service in Kirby
We install materials you can look up, not mystery brands off a van. For Kirby additions and ADUs, that often means Windows & Doors - Kirby specialists like Simonton on the new exterior walls, Ply Gem for siding and trim details, and PGT for impact-rated glazing where the code or your insurance requires it. We carry these lines because they hold up through San Antonio’s hard freezes, like the February 2021 Uri event that exposed how poorly many older Kirby homes were winterized. You’ll know exactly what’s going on your house before we order it.
Common Home Additions & ADU Problems We See in Kirby Homes
- Galvanized plumbing and overloaded electrical panels. Tearing open a 1950s-70s Kirby slab home during a garage-to-ADU conversion regularly turns up original galvanized pipes or an electrical panel that can’t carry the added load. Kirby’s code requires upgrades before we can close the walls, and we budget for that in writing.
- Expansive clay movement cracking slabs and tilting walls. Kirby sits on some of the most reactive clay soil in Bexar County. Additions and ADU foundations that aren’t engineered for soil movement heave within a few seasons, leaving cracked drywall and doors out of square.
- Second-story framing over an existing slab without structural verification. A room addition or upper floor over a 1960s slab that was never sized for it will fail Kirby’s rough-in inspection. We check the foundation load path before we frame, so the inspector signs off instead of halting the job.
- Rotted sill plates and aluminum wiring behind load-bearing walls. Kirby’s ranch homes have been through decades of slab movement and humidity swings. Rotted framing and outdated wiring are common, and they have to be corrected before inspection sign-off. We handle that with written change orders, not surprises.
Pricing for Home Additions & ADU in Kirby, TX
Here’s what we see in Kirby’s market as of 2026. These ranges reflect local labor, Kirby’s inspection schedule, and the structural realities of building on expansive clay.
| Project Type | Typical Range in Kirby |
|---|---|
| Room Addition | $45,000 – $130,000 |
| ADU Construction | $90,000 – $220,000 |
| Garage Conversion | $30,000 – $80,000 |
What moves the price? Foundation work on clay soil is often the single biggest variable. A garage conversion with a stable slab and modern electrical comes in lower. A room addition that requires structural reinforcement, panel upgrades, and soil correction lands higher. Every estimate we give is a written line-item quote, and every price change arrives as a written change order before work happens. No surprise invoices at the end. Call (877) 610-1318 to schedule your free estimate.
We Also Serve Cities Near Kirby
If you’re outside Kirby’s 78244 ZIP but close by, we handle additions and ADUs across Windcrest, Converse, Live Oak, and Universal City too. Same owner-operated crews, same written change orders, same 90-Day Done Right Promise. Home Additions & ADU in Kirby and the surrounding towns are what we do every week.
Serving Kirby, TX - Our Local Coverage Area
We’re based in the Kirby 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 Kirby
Yes, you need a Kirby city permit, and no, San Antonio’s process does not apply. Kirby is a fully independent municipality completely encircled by San Antonio, and Kirby City Hall runs its own inspections and code enforcement. Pulling a permit from San Antonio or assuming Bexar County jurisdiction applies will stop your job. We pull all permits through Kirby’s own offices from the start. Call (877) 610-1318 if you want us to check your address and confirm which jurisdiction applies before you spend a dollar.
The most common hidden issues in 1960s Kirby ranches are aluminum wiring feeding original panels, galvanized plumbing at the end of its service life, and rotted sill plates from decades of slab movement on expansive clay. Kirby’s code requires correcting these before we close the walls, and we write the allowances for those corrections into the contract up front. You’ll know the cost before we open the wall, not after. Call (877) 610-1318 for an exact quote on your specific home.
Kirby sits on the eastern Bexar County expansive black-clay soil belt, where dramatic seasonal moisture swings cause slabs to heave and settle repeatedly. A detached ADU foundation has to be engineered for that movement, including proper footings, drainage, and soil preparation. Otherwise the slab cracks, walls bow, and doors go out of square within two seasons. We size the foundation for Kirby’s soil from the first drawing. Estimates are free. Call (877) 610-1318.
Because Kirby is its own city with its own permitting and inspection system, and a contractor used to San Antonio’s schedule gets caught off guard. Kirby City Hall runs inspections on a smaller-office timeline, and an address that looks like San Antonio is actually inside Kirby’s city limits. That changes plan review, inspection scheduling, and code requirements. We know which side of the invisible boundary your home sits on before we quote the job. Call (877) 610-1318.
In many cases, yes. A junior ADU or interior conversion can often work without a full separate entrance, depending on what Kirby’s current code allows for egress, occupancy, and kitchen facilities. We check the specific requirements for your home and your proposed layout before you commit. If a separate entrance is required, we’ll tell you in writing with the cost attached. Call (877) 610-1318 and we’ll walk your house and give you a straight answer.
Get Your Free Estimate for Home Additions & ADU in Kirby
If you live in Kirby and you’re thinking about a room addition, a garage conversion, or a new detached ADU, call (877) 610-1318. We’ll come out, look at your house, review Kirby’s permit requirements, and hand you a written line-item estimate. Every job is backed by the 90-Day Done Right Promise: if it’s not done right, Tom comes back and makes it right, one call. Permits pulled, inspections signed, and every price change in writing before a single nail moves.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Kirby since 1998.