A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateTrusted ADU Builders for Houston Homeowners
Adding a second home to your Houston lot, whether it’s a detached backyard unit, a garage conversion, or a room addition, means opening your property to a construction crew for months. The question most homeowners quietly wrestle with is simple: who exactly is walking through the gate every morning? Sutton ADU Houston answers that before the first tool is lifted. Since 2006, Miles Hartwell and our team have built accessory dwelling units across Houston under The Threshold Standard: a written price locked before work begins, a 365-Day Done Right Promise in writing, and a crew fully background-checked, identity-verified, and photo-badged. We send you the name and photo of every person arriving at your door before they show up. If you’re pricing an ADU in Houston right now, call (940) 242-3207 for a free, no-obligation estimate.
Most detached ADUs in the Houston market run between $180,000 and $320,000 before site work, depending on size, foundation type, utility runs, and finishes. That’s a real range, not a teaser number. We’d rather you know the truth before you call than discover it halfway through a design meeting.
ADU Construction
ADU Construction is the full build process of an accessory dwelling unit on your Houston property, from the first site survey and foundation pour through framing, rough-in, drywall, finishes, and final inspection. You need it when you’re adding a rentable unit, a home for an aging parent, or a private space for adult kids who moved back and aren’t leaving. Sutton ADU Houston handles every phase, and we give you one written price for the complete build before we mobilize, not a cost-plus arrangement that lets the budget drift. In Houston’s clay-heavy soils, foundation work on a detached ADU often runs $15,000 to $35,000 depending on slab vs. pier-and-beam and soil testing results. Call (940) 242-3207 to have us walk your lot and price it properly.
Site Preparation and Utilities
Houston lots bring surprises: expansive clay that shifts, mature live oaks with root systems you can’t trench through, drainage patterns that change after a hard rain. We map all of it before we quote. The quote includes utility runs, grading, and any tree protection required by city ordinance, so you’re not getting a change order two weeks in.
Build Quality and Inspections
We pull permits on every ADU construction project in Houston and schedule all city inspections ourselves. The 365-Day Done Right Promise covers defects in workmanship for one full calendar year from project completion. If something isn’t right, we return and make it right, no second invoice.
Detached ADU
A Detached ADU is a fully separate living structure built in your backyard, complete with its own entrance, kitchen, bathroom, and addressable space. It’s the right choice when you want rental income without sharing walls, or when an aging parent needs independence but you need them close. Sutton ADU Houston builds detached units from the foundation up, including prefab and modular lines like Dvele and Boxabl when the lot and budget fit. A detached ADU in Houston with site work, utilities, and standard finishes typically runs $220,000 to $320,000. Smaller studio units can land closer to $180,000 on a flat, clear lot. We give you a hard number before you sign anything.
Prefab vs. Stick-Built
Prefab lines like Dvele and Boxabl can cut on-site build time significantly, sometimes by 30 percent or more, but they require crane access and a flat, clear staging area. On tight Houston lots with alley access or overhead power lines, stick-built often wins. We’ll walk you through both options with real numbers for your specific property.
Foundation Choices in Houston Soil
Houston’s gumbo clay expands when wet and contracts in drought. That makes foundation selection a bigger deal than most homeowners expect. We test the soil, look at your drainage, and recommend slab or pier-and-beam based on what the ground will actually do over the next thirty years.
JADU
A JADU, or junior accessory dwelling unit, is a smaller living space created within the existing footprint of your home, typically a converted garage, a finished basement, or a partitioned section of the main house with its own entrance and a compact kitchen. It’s the fastest path to an extra unit because there’s no new foundation, no new roofline, and fewer permit hurdles. In Houston, a JADU conversion usually runs $80,000 to $160,000 depending on whether you’re finishing an existing garage with plumbing already nearby or starting from raw space. Sutton ADU Houston handles the entire conversion, including the separate address application and utility sub-metering when Houston code requires it.
When a JADU Beats a Detached Unit
If your lot is narrow, your setbacks are tight, or you want to generate rental income without waiting nine months for a full build, a JADU makes practical sense. Garage conversions in neighborhoods like The Heights and Montrose are common because the garage already exists and the foundation work is minimal. You’re converting, not building.
What the Code Actually Requires
A JADU in Houston still needs its own entrance, a bathroom, and a kitchenette with a sink and food prep area. We handle the code compliance side, including egress windows and fire separation, so your permit goes through without a denial letter.
ADU Plans
ADU Plans are the stamped architectural drawings required by the City of Houston before any accessory dwelling unit can be permitted and built. You need them the moment you decide to move forward; nothing gets approved without a site plan, floor plan, structural details, and energy compliance documentation. Sutton ADU Houston prepares full permit-ready plan sets, including site surveys, foundation design, and structural calculations, as part of our written estimate. Plan costs in Houston typically run $3,500 to $10,000 depending on the unit’s size, whether you need a variance for setbacks, and how many revision rounds the city requests. We quote this as a line item, never as a surprise add-on.
What the City of Houston Reviews
The permitting office checks your plans against setback requirements, impervious cover rules, floodplain maps, and the city’s 2021 construction codes. Houston is in a floodplain-prone region, so elevation and drainage details get real scrutiny. We’ve been through this review enough times to know what gets flagged and how to submit clean the first time.
Prefab Plans vs. Custom Plans
If you’re using a prefab manufacturer like Plant Prefab or Mighty Buildings, their engineering package often covers the structural side, but the site plan, foundation, and utility drawings still have to be done locally. We handle that coordination so you’re not stuck as the messenger between a factory in California and a permit clerk in downtown Houston.
ADU Contractor
An ADU Contractor is the licensed general contractor who holds the permit, manages the subcontractors, orders materials, handles inspections, and carries the liability for the entire accessory dwelling unit build. You need one whenever the project involves foundation work, structural changes, or plumbing and electrical rough-in; this is not a handyman job. Sutton ADU Houston is the ADU-specialist member of the Threshold Group family, and every person we send to your Houston property has been background-checked, identity-verified, and photographed before they arrive. General contractor fees on a Houston ADU are typically embedded in the total project price, which for most builds lands between $180,000 and $320,000. We don’t charge hourly for management; you get one written price and it doesn’t move.
What Separates a Real ADU Contractor From a Handyman
A handyman can build a shed. An ADU contractor pulls permits, passes structural and MEP inspections, and carries the insurance the city requires before it will issue a certificate of occupancy. Houston won’t let you rent or occupy an unpermitted unit, and your homeowners insurance carrier may deny a claim on unpermitted work. We’re the contractor the permit office knows by name.
The Threshold Verified Difference
Every Sutton ADU Houston field technician is background-checked and identity-verified. Their name and photo are sent to you before the visit. They arrive in a clean, marked uniform and show a photo ID badge at the door, every time. That’s The Threshold Standard, and it’s the reason a homeowner who is often home alone, or who has young kids, can open the door without hesitation.
ADU Design
ADU Design is the process of planning the unit’s layout, appearance, and function on your specific Houston lot, before construction drawings are finalized. It covers everything from where the unit sits relative to your house and property lines, to how the kitchen and bathroom lay out, to what the exterior looks like from the street. You need it because a poorly placed ADU can block drainage, violate a setback (the required gap between your new structure and the property line), or simply feel wrong in your yard. Design fees in Houston typically fall between $2,000 and $8,000 as part of a larger project. Sutton ADU Houston includes design in our written price so you’re not paying a separate architect out of pocket.
Lot Fit and Orientation
Houston lots vary wildly, from 40-foot-wide bungalow parcels in Montrose to half-acre spreads in Kingwood and Atascocita. We start every design with a site analysis: sun angle, prevailing wind, drainage flow, and where the unit’s entrance should face so it doesn’t feel like it’s staring at your kitchen window. These are the decisions that determine whether the unit rents quickly or sits empty.
Materials That Survive Houston Weather
Houston means heat, humidity, and the occasional named storm. We specify James Hardie fiber cement siding on most builds because it handles moisture without warping or mildewing the way wood trim does in our climate. Roofing, flashing, and insulation details are specified for Houston’s wet seasons, not for a California coastal model that looks pretty in a catalog.
Backyard ADU
A Backyard ADU is a detached accessory dwelling unit built in the rear yard of your Houston property, behind the primary residence, typically accessed by a side path or alley. It’s what most people picture when they hear “ADU”: a small house in the back with its own small porch, maybe 400 to 800 square feet. Sutton ADU Houston has built backyard units across Houston from The Woodlands down to Pearland, and we work with prefab manufacturers including Boxabl and Plant Prefab when the lot access supports it. A backyard unit with a one-bedroom layout and standard finishes in Houston generally costs $200,000 to $300,000 including site work. A larger two-bedroom unit pushes past $300,000. Call (940) 242-3207 and we’ll give you a number for your specific yard, not a brochure range.
Setback and Impervious Cover Rules
Houston’s code requires a minimum gap between your new structure and the property line, and limits how much of your lot can be covered by buildings and paving. On smaller lots in neighborhoods like Oak Forest or Garden Oaks, this is often the deciding factor between a 500-square-foot unit and a 750-square-foot one. We survey the lot and tell you exactly what fits, before you pay for plans.
Rental Income Math for Houston
A one-bedroom Backyard ADU in a central Houston neighborhood rents for roughly $1,200 to $1,800 a month depending on finishes, parking, and proximity to the Medical Center or downtown. At a $250,000 build cost, that’s a gross yield around 6 to 8 percent before expenses. It’s not passive income, but it’s reliable income, and we’ll give you the honest breakdown on what your specific unit will likely rent for.
Brands We Service
Sutton ADU Houston works directly with several leading prefab and modular ADU lines, and we’re fluent in what each one does well and where each one stumbles on a Houston lot. Dvele builds high-performance, factory-finished units with airtight envelopes and excellent humidity control, which matters in a city where the dew point sits above 70 degrees for six months a year. We’ve installed Dvele units on tight urban lots in the Heights and know their crane requirements, foundation tolerances, and the local inspection points that usually need extra documentation. Boxabl units are smaller, more affordable, and fast to deploy, but they have specific foundation and utility connection specs we coordinate before the unit ever leaves the factory. Plant Prefab offers more architectural flexibility and works well for larger two- and three-bedroom units when the budget and lot size allow the higher square-foot cost.
Whether you have a Dvele, a Boxabl, a Plant Prefab unit, or any other make, we can handle the site work, foundation, utility connections, and finish work around it. The manufacturer builds the box; we build everything that box sits on and connects to. That’s the part that determines whether the unit actually works in Houston’s soil and climate.
Signs You Need a Pro Right Now
- Your lot has drainage or flooding history. Houston is flat, clay-heavy, and flood-prone. If water pools anywhere on your property after a hard rain, your ADU’s foundation design and grading plan need a professional eye before you spend money on plans. A unit built in the wrong spot becomes a mold liability and an insurance headache.
- You live in a flood zone or near a bayou. Brays Bayou, Buffalo Bayou, White Oak Bayou: if you’re within a few blocks of any of them, your ADU will trigger elevation and floodplain review, and possibly a variance hearing. We’ve handled enough of these to know what passes and what doesn’t. A DIY permit attempt here usually ends in a denial letter and lost months.
- Your garage has visible wall cracks or slab settling. If you’re considering a garage conversion and the existing slab is cracked or the walls are pulling away from the framing, you have a structural question, not just a remodeling question. We’ll tell you if the garage is worth converting or if you’d be throwing good money after bad.
- You have large trees within 20 feet of the planned build site. Houston live oaks are protected in some jurisdictions, and their root zones can’t be trenched through without an arborist’s sign-off. The wrong excavation kills the tree and puts you on the hook for city fines. We handle tree protection planning as a standard part of site prep.
- Your HOA or deed restrictions mention ADUs. Many Houston-area communities, especially master-planned areas like Cinco Ranch and parts of Clear Lake, have deed restrictions that limit or prohibit accessory dwelling units. We research your deed record and HOA covenants before you spend a dollar on plans, so you don’t discover the restriction after paying for design work.
Our Process, Step by Step
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Initial call and lot assessment. You call (940) 242-3207 and speak to a live person, not a voicemail tree. We ask about your lot, your goals, and your budget. If it makes sense, we schedule a site visit with Miles or a senior project lead. The site visit is free.
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Site survey and feasibility. We walk the lot, measure setbacks, check soil conditions, map utility locations, and review any HOA or deed restrictions that apply. We tell you what’s buildable, what’s not, and what it will realistically cost. This is where most homeowners learn the difference between a catalog floor plan and a plan that actually fits their Houston yard.
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Written, line-item estimate. You receive a written price covering the entire project scope before any work begins. Not a range. Not a verbal ballpark. A line-item document that tells you exactly what you’re paying for. If the scope doesn’t change, the price doesn’t change. No change orders passed silently to the bill.
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Permits and plans. We prepare the full permit package, including site plans, structural drawings, energy calculations, and drainage details, and we submit it to the City of Houston. We manage every comment, revision, and inspection scheduling. You don’t chase the permit office; that’s our job.
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Build and completion. Construction proceeds on the schedule we both agreed to. You get a written update at each major milestone, and every one of our technicians arriving on your property has been background-checked, identity-verified, and photo-badged with their name and photo sent to you ahead of time. The build is governed by the 365-Day Done Right Promise: if the work isn’t right within a full year, we make it right.
How Much Does ADU Builders Cost in Houston?
A typical detached ADU in Houston runs $180,000 to $320,000 before site work, depending on square footage, finishes, foundation type, and utility run distances. A JADU or garage conversion lands lower, usually $80,000 to $160,000, because the shell already exists. If you’re adding a room addition to the main house rather than a separate unit, costs in Houston typically fall between $60,000 and $180,000 depending on whether you’re adding a bedroom or a full primary suite with a bathroom.
What moves the price: soil conditions and foundation requirements, how far utilities have to be trenched from the main connection, whether the lot allows crane access for prefab delivery, the level of interior finishes you choose, and whether HOA or city variance hearings add time and fees. A $220,000 build and a $300,000 build can look nearly identical on paper; the difference is usually under the slab and inside the walls.
How to avoid overpaying: get a written price that includes site work, permits, plans, and utility connections in one document. If a contractor gives you a low square-foot price and then bills site work, permits, and utility runs as separate line items after the fact, you’re not saving money, you’re being quoted a teaser number. Our free estimate includes everything: plans, permits, foundation, site work, utilities, and the build itself. One number. In writing. Before you commit.
Our Service Area Near Houston
Sutton ADU Houston builds across the entire Houston metro, from ADU Builders in Houston proper to the surrounding communities. We serve ADU Builders in The Woodlands, ADU Builders in Pearland, plus Humble, League City, Atascocita, Baytown, Mission Bend, La Porte, Rosenberg, Fresno, and Cinco Ranch. If you’re within about 45 minutes of downtown Houston, we’re likely already working in your neighborhood. Site visits are free, and the estimate you get is the price you’ll pay.
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.
Frequently Asked Questions About ADU Builders in Houston
An ADU builder is a contractor who specializes in accessory dwelling units: detached backyard units, garage conversions, and junior ADUs built within an existing home’s footprint. Sutton ADU Houston handles the entire process from site survey and plans through permits, construction, and final inspection. Call (940) 242-3207 to discuss your lot and what’s buildable on it.
Most detached ADU builds in Houston take 6 to 10 months from signed contract to certificate of occupancy. Prefab units from manufacturers like Dvele or Boxabl can compress the on-site build to 3 to 5 months, but site work, foundation, and permitting still run on the city’s schedule. We give you a written timeline with your estimate.
A detached ADU in Houston typically costs $180,000 to $320,000 including site work, permits, and standard finishes. A JADU or garage conversion runs $80,000 to $160,000. The exact number depends on your lot, soil conditions, utility distances, and finish level. Call (940) 242-3207 for a free estimate with a written, line-item price.
Yes. We work directly with Dvele, Boxabl, and Plant Prefab, handling site preparation, foundation work, utility connections, and all finish work around their factory-built units. We know each brand’s delivery requirements and Houston inspection points. The manufacturer builds the box; we build everything it sits on and connects to.
Our live-answer line at (940) 242-3207 is staffed 24 hours a day, 7 days a week. If you have a structural concern, a drainage issue after a storm, or a build milestone that needs immediate attention, you’ll speak to a person, not a voicemail tree. The 365-Day Done Right Promise includes a free second visit if any element of the build fails within a full year.
The 365-Day Done Right Promise covers defects in workmanship for one full calendar year from project completion. If the work isn’t right within that year, Sutton ADU Houston returns and makes it right at no charge. It’s a written guarantee stamped on every project, not a verbal assurance.
Start by gathering your property survey if you have one, any HOA documents or deed restrictions, and a rough idea of your budget and intended use for the unit. We’ll handle the rest: soil testing, utility mapping, permit research, and the written estimate. The site visit is free, and you’ll know exactly what’s buildable before you spend anything on plans.
Schedule Your ADU Builders Service in Houston Today
You deserve a builder who tells you exactly who’s coming to your property and puts the price in writing before the first tool is lifted. Call (940) 242-3207 to schedule your free estimate with Sutton ADU Houston. Miles Hartwell and the team will walk your lot, answer your questions straight, and hand you a written price you can plan around. No pressure, just numbers.
Written by Miles Hartwell, Owner at Sutton ADU Houston, serving Houston since 2006.
