A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Houston, TX
Adding an ADU in Houston means building on slab-on-grade clay soil, under hurricane wind codes, and often without a traditional zoning map to guide you. Sutton ADU Houston works within that reality every day. We’re the ADU-specialist member of the Threshold Group family, founded in 2006, and every project carries a written price before work starts and a 365-Day Done Right Promise after it ends. Call (940) 242-3207 to talk through your lot and your budget.
Why Houston Homes Are Different
Houston’s housing stock is dominated by wood-framed, brick veneer or HardiePlank ranches built from the 1950s onward, mostly on generous lots of 5,000 to 7,500 square feet. That sounds ideal for an ADU until you factor in the expansive clay soils under most of the city. These soils swell and shrink with rain and drought, so a new ADU foundation needs engineering that accounts for differential movement or you’ll see cracks within a few years. We specify pier-and-beam or reinforced slab designs based on soil tests, not guesswork.
The climate adds a second layer. Houston’s long cooling season means an ADU’s HVAC has to be sized for humidity removal first, not just temperature. And hurricane-driven wind and localized flooding make resilient design and drainage planning non-negotiable. In older inner-loop neighborhoods like Montrose and the Heights, we often work with detached garages from the 1920s and 1940s that were never meant to hold a second story. Their footings are routinely undersized, which means reinforcement or replacement before any framing goes up.
Our Main Houston Services
Houston homeowners most often call us about two things: adding square footage to the main house, or building a separate unit in the yard. Here’s what each involves locally.
Home Addition Contractor in Houston
A home addition in Houston usually means extending off the back or side of a 1950s ranch, and that brings foundation work into play immediately. The new slab or pier system has to tie into the existing one without creating a hinge point, which is a real concern on expansive clay. We also check the lot coverage rule, because Houston caps impervious coverage at 30% for a 5,000-square-foot lot, and an addition can push you over. Read the full breakdown on our Home Addition Contractor in Houston page.
ADU Builders in Houston
Houston has no formal zoning code, which surprises a lot of homeowners. What actually governs an ADU here is a patchwork of deed restrictions, Harris County floodplain rules, and that 30% lot coverage cap on a standard 5,000-square-foot lot. A detached unit is often the cleanest path to rental income because it doesn’t trigger the same coverage math as an attached addition. We navigate those rules and build foundations that stand up to clay soil. See the details on our ADU Builders in Houston page.
Room Addition Contractor in Houston
A room addition in Houston frequently means converting a covered patio or extending a bedroom wing, and the moisture question comes first. Houston’s humidity and heavy rain events punish any wall assembly that traps vapor, so we spec drainage planes and flashing details that shed water instead of holding it. Older homes in Montrose or the Heights often have framing that no longer meets wind load code, so part of the job is bringing the existing structure up to standard before we add to it. Learn what’s involved on our Room Addition Contractor in Houston page.
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.
Brands We Service in Houston
We work with Dvele, Mighty Buildings, and Boxabl systems alongside traditional site-built construction. When the lot or the budget favors a prefab route, we can usually get a factory-built unit permitted and placed faster than a stick-built ADU. See the full list on our brands page.
Pricing for ADU Company in Houston, TX
| Service | Typical range in Houston |
|---|---|
| Detached ADU, 400 – 600 sq ft | $180,000 – $260,000 |
| Detached ADU, 600 – 800 sq ft | $220,000 – $320,000 |
| Detached ADU, 800 – 1,000 sq ft | $280,000 – $380,000 |
| Garage conversion to ADU | $110,000 – $190,000 |
| Garage apartment over existing garage | $150,000 – $240,000 |
| Home addition, 200 – 400 sq ft | $90,000 – $150,000 |
| Home addition, 400 – 600 sq ft | $120,000 – $190,000 |
| Home addition, 600 – 800 sq ft | $160,000 – $240,000 |
| Room addition, single room | $50,000 – $90,000 |
| Foundation repair or upgrade for ADU | $12,000 – $30,000 |
| Flood vents and site drainage work | $8,000 – $22,000 |
What pushes a Houston ADU price up is usually soil. Expansive clay means deeper piers or a stiffer slab than you’d need in other Texas markets, and floodplain requirements can add vents, elevation, or drainage engineering. Whatever the number is, you’ll see it in writing before we start, and that written price doesn’t change unless you change the scope.
Neighborhoods We Serve in Houston
We run ADU and addition projects across the city, from the tight inner-loop lots to the wider suburban spreads. The older the neighborhood, the more likely we’re reinforcing an existing garage before building on top of it.
- Montrose
- The Heights
- West University Place
- Meyerland
- Spring Branch
Most Houston estimates are scheduled within a few business days of your call, and we’ll send you the name and photo of who’s coming before they arrive.
Service Area – Cities Near Houston
Our Houston office also schedules projects in the surrounding communities. If you’re in Bellaire, TX dealing with a tight lot, Humble, TX with floodplain considerations, Pearland, TX with newer slab homes, or La Porte, TX near the bay with wind exposure, we can bring the same written-price and 365-Day Promise standard to your project.
Serving Houston, TX - Our Local Coverage Area
We’re based in the Houston 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 ADU Company in Houston
Yes. Houston requires building permits for any new structure, and if your property sits in a mapped floodplain, you’ll also need floodplain development approval and possibly elevation or venting. Deed restrictions in your subdivision may add their own rules. We pull the permits and handle the paperwork as part of every project.
A detached ADU in Houston typically runs 6 to 10 months from permit to final inspection, depending on soil conditions and whether you’re going site-built or prefab. Prefab units like Dvele or Boxabl can shorten the on-site phase considerably. Call (940) 242-3207 for a realistic timeline on your specific lot.
No, not unless you change the scope. Your written price is locked before we begin, and any change gets its own line-item price in writing before we do the work. That’s the Threshold Standard, and it applies to every project, every time.
Ready to talk through your Houston lot? Call (940) 242-3207 for a free estimate, and we’ll send you a name and a face before anyone steps onto your property. Written by Miles Hartwell, who leads Sutton ADU Houston.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Houston Customers Say
"Good quality build. One delay on cabinets, but they gave a realistic new date and kept to it."
- Gordon B."They handled the drawings and the permit paperwork for us. All I had to do was pick the finishes."
- Rosa M."Great build and clear weekly updates. Plumbing inspection got pushed a week because of the city, which wasn't their fault, but it set us back a bit."
- Lucia P.
