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 Terrell Hills
A full home addition or ADU in Terrell Hills typically runs $45,000 to $130,000 for an addition and $90,000 to $220,000 for a new detached ADU. That’s the honest range for this market. The permit path here is different from almost anywhere else in Texas, and getting it wrong adds weeks. If you’re planning a Home Additions & ADU project in Terrell Hills, call Tom Barrett and his sons at (877) 610-1318. We’ll walk you through the permits, the deed restrictions, and the real numbers before you spend a dime.
Terrell Hills is its own city. You’d never know it driving through, because San Antonio wraps all the way around it. But when you pull a permit for an addition or an ADU, that boundary matters a lot. We know exactly where to file, what the city will ask for, and how the clay soil under your foundation will behave when we dig. That’s the knowledge you’re paying for.
Why Barrett & Sons Construction Is Terrell Hills’s Preferred Home Additions & ADU Company
Tom Barrett founded this company in 1998. His sons run the crews. When you call about a second-story addition or a detached ADU in Terrell Hills, the person who answers the phone is a real human being who knows the difference between Terrell Hills City Hall and the San Antonio permit office. That’s not a small thing here.
We’ve worked on Spanish Colonial Revival homes from the 1930s, Tudor-style houses with load-bearing brick, and mid-century masonry builds that need preservation-sensitive additions. Every job gets a written scope, every price change arrives as a written change order before the work starts, and every permit gets pulled through Terrell Hills, not San Antonio. We also carry the 90-Day Done Right Promise on every contract. If something isn’t right, Tom comes back and makes it right. One call.
Terrell Hills homeowners tend to ask harder questions. They should. The value of the housing stock here means a badly planned addition can cost six figures to fix. We’d rather spend an extra week in planning than rush a foundation pour on Blackland Prairie clay and watch door frames go crooked two years later.
Our Home Additions & ADU Services in Terrell Hills
ADU Design & Permitting
This is the step where Terrell Hills projects go sideways if you hire the wrong crew. Terrell Hills is a fully independent municipality encircled by San Antonio. It operates its own building department, permit office, and code enforcement. Contractors who file ADU permits with San Antonio discover those permits are invalid here and must restart the whole process through Terrell Hills City Hall. We file with Terrell Hills from day one, and we verify deed-restriction compliance before the plans are finalized. The city’s deed restrictions sit on top of building code, so an ADU that meets code can still get denied at the deed-restriction level. We check both before you order a single framing stick.
Garage Conversion ADU
Many Terrell Hills homes from the 1920s through the 1950s have detached garages or carports that could become rental units or guest quarters. The challenge is plumbing. These older garages were never plumbed for kitchens or baths, and tying into the main house’s waste line means trenching through that expansive clay soil. A garage conversion in Terrell Hills typically runs $30,000 to $80,000 depending on whether you need a new sewer lateral, upgraded electrical service, or foundation shoring. Many homeowners pair this with Windows & Doors - Terrell Hills upgrades to match the new unit with the main house. We use Schluter waterproofing systems in the wet areas so tiles don’t crack when the ground shifts seasonally.
New Detached ADU
A new detached ADU is the biggest investment most Terrell Hills homeowners make, short of buying the house itself. $90,000 to $220,000 is the realistic range for this market, and the variance comes down to foundation engineering, site prep, and finishes. Terrell Hills sits on Blackland Prairie clay. That soil swells when it rains and shrinks when it’s dry, and it moves enough to crack a poorly engineered slab. Most detached ADUs here need pier-and-beam or post-tension foundation work. We coordinate with local soils engineers who know this specific clay profile, not a generic spec sheet.
Junior ADU & Interior Conversion
A junior ADU, usually a bedroom with a kitchenette and bath carved out of existing square footage, runs on the lower end of the spectrum but carries the same permit and deed-restriction requirements. Terrell Hills code enforcement is strict about egress, ventilation, and fire separation between units. Interior conversions in older homes often mean working around original plaster, load-bearing brick, and electrical panels that haven’t been upgraded in 50 years. We plan for that before we open a wall. KraftMaid cabinetry and Grohe fixtures give these spaces the same quality level as the rest of the house, which matters in a neighborhood like this.
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 Terrell Hills
We carry real brands you can look up. KraftMaid cabinetry and Cambria countertops in kitchen spaces. Terrell Hills Roofing expertise with GAF materials when an addition ties into a new roofline. Schluter underlayment in bathrooms where older homes shift and settle. These aren’t mystery brands off a van. Terrell Hills homeowners ask what materials we’re using, and we tell them the exact name and model before anything gets ordered. Written allowances in the contract mean you know exactly what you’re getting, and any change to that allowance arrives as a written change order. Nothing gets ordered until you’ve signed off on it.
Common Home Additions & ADU Problems We See in Terrell Hills Homes
- The San Antonio permit trap. Because Terrell Hills is physically surrounded by San Antonio, contractors unfamiliar with the area file permits with San Antonio. Those permits are meaningless here. The project stops, the paperwork restarts at Terrell Hills City Hall, and the schedule adds two to four weeks.
- Deed restriction conflicts. Terrell Hills enforces its own deed restrictions alongside city code. An addition or detached structure can pass a building inspection and still be denied at the deed-restriction level. We verify both before breaking ground, so you don’t pay for plans that can’t be built.
- Blackland Prairie clay movement. The soil under Terrell Hills swells when wet and shrinks in drought. If your addition’s foundation isn’t engineered for that movement, you’ll get slab cracks and misaligned door frames. Post-tension or pier-and-beam systems are often required here, and they’re not optional line items.
- Aging infrastructure in period homes. 1920s-to-1950s Terrell Hills homes often still have original plaster, load-bearing brick, and electrical panels rated for a fraction of modern demand. An addition that adds square footage also adds electrical load, and we account for panel upgrades and structural reinforcement in the written scope, not as a surprise invoice.
Pricing for Home Additions & ADU in Terrell Hills, TX
The lead range for a Terrell Hills addition is $45,000 to $130,000. Here’s the breakdown for the most common project types we quote:
| Project Type | Typical Range in Terrell Hills |
|---|---|
| Home Addition | $45,000 - $130,000 |
| Second Story Addition | $45,000 - $130,000 |
| ADU Construction (new detached) | $90,000 - $220,000 |
What moves the number? Foundation engineering on clay soil, the age of your existing structure, whether you’re matching original plaster or millwork, and the quality level of your finishes. High-end Terrell Hills additions with custom millwork, architectural glass, and designer-specified materials run toward the top of those ranges because the materials themselves carry long lead times. The workmanship isn’t the expensive part. The Cambria slab, the custom KraftMaid cabinetry, the specialty hardware you picked with your designer: that’s where the money goes. And the price is fixed in writing before anything gets ordered. Every change order arrives on paper, with your signature, before work proceeds. Call (877) 610-1318 for a free estimate. We’ll give you real numbers, not a teaser quote.
We Also Serve Cities Near Terrell Hills
Our crews work throughout the surrounding area, including Alamo Heights, San Antonio, Windcrest, and Kirby. Each municipality has its own permit process, its own deed restrictions, and its own soil quirks. We know the differences because we work in all of them. If you’re in Terrell Hills or one of the nearby cities, Home Additions & ADU in Terrell Hills call us at (877) 610-1318 and we’ll tell you what applies to your specific address.
Serving Terrell Hills, TX - Our Local Coverage Area
We’re based in the Terrell Hills 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 Terrell Hills
Terrell Hills is a fully independent municipality with its own building department, permit office, and code enforcement. Permits filed with San Antonio are not valid in Terrell Hills. You must file through Terrell Hills City Hall, and starting your paperwork in the wrong city means restarting the entire process. That’s a two to four week delay most homeowners don’t plan for. We file with Terrell Hills from day one, so the schedule you sign off on is the schedule that actually happens. Call (877) 610-1318 and we’ll check your specific address before you submit anything.
Terrell Hills enforces its own deed restrictions alongside the building code. A detached ADU or garage conversion can receive a building permit and still be denied at the deed-restriction level. The restrictions govern setbacks, exterior appearance, height, and sometimes the very existence of detached structures. We verify deed compliance with Terrell Hills before we finalize plans, so you don’t pay for drawings that can’t be approved. This double-approval layer is a Terrell Hills specific issue that doesn’t apply in most surrounding cities.
Terrell Hills sits on Blackland Prairie clay that swells during wet seasons and shrinks during droughts. Any addition or ADU foundation must be engineered for that movement. Post-tension slabs and pier-and-beam systems are the two most common solutions here, and the choice depends on your existing foundation type, the addition’s size, and the soil report. We bring in local soils engineers who know this specific clay profile. Skipping this step saves money now and costs far more later, when the addition pulls away from the original structure and door frames stop closing. Call (877) 610-1318 for an exact scope based on your lot.
We order long-lead items before demolition starts. Custom millwork, Cambria countertops, KraftMaid cabinetry, and architectural glass can run 8 to 14 weeks from order to delivery. On a 1930s Spanish Colonial Revival home near Terrell Hills City Hall, we waited through a 10-week millwork lead time before framing, and the permit and deed compliance sign-offs were secured before any rough-in. The schedule is driven by materials, not labor. Your contract reflects that. Prices are fixed in writing before any order is placed, so a cabinet upgrade doesn’t become a surprise invoice later.
Older Terrell Hills homes often have original plaster, load-bearing brick, and electrical systems rated for far less demand than a modern addition requires. Matching plaster texture to a new stairwell, reinforcing load-bearing walls without disturbing original millwork, and upgrading an electrical panel from the Eisenhower era all require planning that generic contractors skip. We’ve coordinated second-story additions on these homes where the final punch list included matching the original plaster to the new framing. It’s slower work. It’s also the only way to do it in a neighborhood where preservation matters. Call (877) 610-1318 for a free estimate and we’ll tell you exactly what your house needs.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Terrell Hills and surrounding communities since 1998.