A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Room Addition Contractor Across Four Corners
Adding a room to your Four Corners home usually runs $85,000 to $190,000 for a standard 300 to 600 square foot addition, and most projects take 3 to 5 months from permit to final walkthrough. That’s the honest range, and it’s the number we start with because you deserve a real figure before anyone asks for your time. Our crews work throughout Four Corners on acreage lots and newer subdivisions, and we coordinate scheduling from our Houston office. Call (940) 242-3207 and we’ll give you a written line-item price before any work begins.
Why Sutton ADU Houston Is Four Corners’s Preferred Room Addition Contractor Company
Four Corners is a different kind of build site. You’re often working with an acre or more, a septic system instead of city sewer, and Fort Bend County permitting rather than a city inspections office. We’ve walked enough of these lots to know what that means for your foundation, your utility runs, and your timeline.
Our Room Addition Contractor team sends you the name and photo of every technician before they arrive. No anonymous crews pulling up to your gate. That matters on acreage where you might be home alone or have kids playing out back.
Every Four Corners project is governed by The Threshold Standard: a written price before work begins, a 365-Day Done Right Promise covering workmanship, and a free second visit if any element fails within the year. Miles Hartwell, who leads our team, signs off on that standard for every build. We’ve been doing this since 2006, and the guarantee is stamped on every contract.
We also know the local permitting path cold. Fort Bend County handles ADU and addition approvals directly here, with no city-level inspection. That speeds things up, but it also means the builder carries the code-compliance responsibility. We self-enforce electrical, septic, and structural standards on every Four Corners job, with third-party engineering verification where it counts.
In Law Suite Builders in Four Corners
In Law Suite Builders in Four Corners help homeowners add a self-contained living space, typically 400 to 900 square feet, with its own entrance, bathroom, kitchenette, and often a separate HVAC zone. On Four Corners lots, these suites frequently go behind the main house or attach at a side wing, which works well on acreage where setbacks aren’t pinching you from every angle.
Expect to spend $110,000 to $220,000 for a detached in-law suite in Four Corners, depending on finish level, foundation type, and whether your septic system needs a field expansion. A 500-square-foot suite with a single bathroom can often tie into an existing tank if it was sized generously. Add a second bathroom and you may be looking at new drain-field work, which runs $8,000 to $25,000 depending on the lot.
Foundation and Utility Considerations
Clay soil and occasional heavy rain in Four Corners mean the slab or pier foundation decision matters more than the paint color. We typically recommend a raised slab, often 12 to 24 inches above grade, to keep water moving away from the sill plate. On flat lots with no existing drainage plan, we’ll scope a shallow swale into the quote. That’s the kind of thing that isn’t optional here.
Scope Lock Before the First Tool
We walk your Four Corners property with a site plan, mark the septic tank and field lines, check well setbacks if you have one, and note any easements. Then we give you a written price. Not a range on a napkin. A line-item quote that tells you what the foundation costs, what the electrical tie-in costs, and what the county permit fee is.
ADU Conversion in Four Corners
ADU Conversion in Four Corners usually means converting an existing structure, like a detached garage, a workshop, or a barn shell, into livable square footage. This is one of the most cost-effective ways to add a rental unit or guest quarters on Four Corners acreage, because the framing, roof, and often the slab are already there.
Conversions in Four Corners run $70,000 to $150,000 for a standard two-car garage or similarly sized outbuilding, assuming the existing structure is structurally sound. The big-ticket items are usually insulation, HVAC, plumbing rough-in, and bringing the electrical panel up to code. If the building was never insulated or finished, you’ll pay more per square foot than new construction, because we’re working inside an existing envelope.
Outbuilding and Shop Conversions
Many Four Corners properties have metal shops, Tuff Shed structures, or older barns that a homeowner wants to turn into living space. These take engineering attention: metal buildings need interior framing to hold drywall, insulation, and wiring, which adds $15,000 to $35,000 depending on size. We’ll tell you early if the structure is worth converting or if you’d be better off starting fresh.
Septic Reality Check
A conversion with a bathroom almost always triggers septic scrutiny. The existing tank was likely sized for the main house only. We scope the drain field and tank capacity during the estimate, because the worst surprise in a Four Corners conversion is tearing up the yard for a larger septic system after walls are already framed.
Trusted Brands We Service in Four Corners
We work regularly with prefab shells from Dvele, Boxabl, and Plant Prefab, plus James Hardie siding and trim systems. If you’ve been researching a prefab ADU or addition kit, we’ll give you straight guidance on which product line fits your lot, your budget, and your timeline. We stock standard parts locally and can get manufacturer-specific components to Four Corners fast when a build is underway. Call (940) 242-3207 and we’ll talk through your options without a sales script.
Common Room Addition Contractor Problems We See in Four Corners Homes
- Wrong jurisdiction assumptions. Homeowners waste weeks submitting plans to a city building department that doesn’t handle Four Corners ADUs. Fort Bend County issues the permits here, and we file there from day one.
- Septic field setbacks underestimated. A new bedroom or bathroom increases the load on your existing system. If the tank or drain field is undersized, you’ll need an expansion, and that can change your budget by $10,000 to $25,000 if it’s not flagged early.
- Flat-lot drainage neglect. Four Corners has plenty of wide-open flat ground, and homes here sit on clay. Without an elevated foundation or a drainage swale, the first heavy spring rain finds its way under your new addition.
- Long material hauls and equipment access. Acreage means longer runs for concrete trucks, septic crews, and material deliveries. We plan for that in the quote instead of letting it show up as a surprise change order.
Pricing for Room Addition Contractor in Four Corners, TX
Here’s what you should expect, in writing, before you sign anything:
- Bump-out addition (200 – 350 sq ft): $65,000 – $110,000
- Standard room addition (350 – 600 sq ft): $85,000 – $190,000
- In-law suite, detached (400 – 900 sq ft): $110,000 – $220,000
- ADU conversion (garage or outbuilding): $70,000 – $150,000
- Septic field expansion (if required): $8,000 – $25,000
- Foundation elevation and grading (flat lot, clay soil): $6,000 – $18,000
Site work, utility tie-ins, and finish selections move the number. That’s why our estimates are line-itemed, so you see where every dollar goes. Call (940) 242-3207 for a free written estimate, and we’ll scope your specific lot before anyone starts hammering.
We Also Serve Cities Near Four Corners
Our crews work across the south Houston metro, including Four Corners, Houston, The Woodlands, Pearland, and Humble. If you’re nearby and considering an addition or ADU, we’ll come walk the property and give you a written price the same way we do here.
Serving Four Corners, TX - Our Local Coverage Area
We’re based in the Four Corners 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 Room Addition Contractor in Four Corners
In Four Corners, you go through Fort Bend County directly. There is no city inspections office for ADUs and additions in unincorporated Four Corners, so the county issues the permits and the builder carries the responsibility for code compliance. This can speed up approval compared to incorporated neighbors like Sugar Land or Missouri City, but it means you need a contractor who self-enforces electrical, plumbing, and structural standards instead of waiting for an inspector to catch problems.
We’ve filed Fort Bend County permits for additions and ADUs across Four Corners, and we pull third-party engineering verification when the project scope warrants it. Call (940) 242-3207 and we’ll tell you exactly which permits your lot needs.
Septic setbacks often dictate precisely where your addition can sit. Fort Bend County requires specific distances between a structure and the septic tank, drain field, and any reserve field area, and on smaller acreage lots that can squeeze your buildable footprint more than you’d expect. A setback is the required gap between your new structure and a property line, well, or septic component.
We locate the tank and field lines during the estimate, then mark the usable building area on your site plan. It’s part of the free written quote. Call (940) 242-3207 to schedule a walkthrough.
No, you cannot build over a well line or wellhead. Fort Bend County requires clearance around wells, and burying a well line under a slab creates a maintenance and contamination risk no inspector or engineer will sign off on. If your proposed addition footprint crosses the well line, the line gets rerouted or the addition shifts.
We flag this during the initial site walk, before you’ve committed to a floor plan. Rerouting a well line typically runs $3,000 to $8,000 depending on distance and terrain. Call (940) 242-3207 and we’ll check your lot before you finalize any plans.
We recommend a raised slab, typically 12 to 24 inches above surrounding grade, on flat Four Corners lots with expansive clay soil. Clay swells when wet and shrinks when dry, and a poorly supported slab will move with those shifts. A raised slab with proper rebar and post-tensioning resists that movement and keeps water from entering at the sill plate.
For detached ADUs on low-lying acreage, we often add a compacted fill pad and a shallow drainage swale. This is standard practice for us in Four Corners, not an upgrade we spring on you later. Call (940) 242-3207 for a foundation recommendation specific to your lot.
It can, yes. Fort Bend County reviews septic capacity when a project adds bedrooms or bathrooms, because the system was sized for the original house. A new addition with a bathroom can push you over the tank’s rated capacity, which triggers a tank replacement or drain field expansion before the addition receives final approval.
On a 1.2-acre lot off Sienna River Parkway, our crew framed a 600-square-foot detached ADU using a Plant Prefab shell and James Hardie siding, routing a new septic line to a field 80 feet behind the main house because the existing tank was sized for only three bedrooms. We brought in a grading team to raise the slab 18 inches above the flood-prone clay, and since there was no city inspector, we pulled a Fort Bend County electrical permit and had a third-party engineer verify the panel tie-in before drywall. That’s how we handle the septic question, and it’s why our quotes account for it up front. Call (940) 242-3207 and we’ll assess your system before you commit to a build.
Written by Miles Hartwell, Owner at Sutton ADU Houston, serving Four Corners with written pricing and the 365-Day Done Right Promise since 2006.
