







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 Grapevine
Room additions in Grapevine typically cost between $180 and $320 per square foot before permit fees, depending on whether you’re building on a standard slab in a 1980s subdivision or matching historic brick in the older central neighborhoods. That puts a 400-square-foot addition in the $72,000 to $128,000 range for most Grapevine lots. Call (903) 342-8977 and we’ll put a written price in front of you before any work starts.
We know Grapevine’s permit desk, its Historic Preservation Commission, and the drainage reality of building near the lake. When you work with our Room Addition Contractor team, you work with people who’ve already done the job on lots like yours. No vague estimates. No surprises at the final invoice. The price goes in writing on day one and stays there.
Grapevine is not a generic suburb. The rules change block by block. Historic District requirements on one side of Main Street, county-style acreage questions on the other, and a lake that pushes humidity into every wall cavity. That’s why local knowledge matters less than you’d think, until you’re standing in front of a rejection letter from the Preservation Commission. Then it matters a lot.
Why Fielding ADU Dallas Is Grapevine’s Preferred Room Addition Contractor Company

We’re an independently owned and operated member of the Garrison Partners family, founded in 2006. Fielding ADU Builders exists to do ADUs and room additions, and in Grapevine, that work has to be right. Reed Calloway leads our team, and the standard he holds is simple: show up in the window, price in writing, build by the book, leave it clean, stand behind it for a year.
Grapevine homeowners call us because the written guarantee matters. The Garrison Standard covers workmanship defects for 365 days. If something fails inside that year, we return at no charge and correct the defect. That’s on paper, not a handshake. Most contractors in this market won’t put that sentence in writing.
Every crew member on a Grapevine job is background-checked and arrives in uniform. You know exactly who is on your site, and a live person answers our phone 24 hours a day, 7 days a week. Call at noon or midnight, someone picks up. No voicemail queue.
We don’t build spec-grade boxes next to 1905 Craftsmans. We pre-check Grapevine’s historic preservation guidelines before drawing plans, because we’ve watched too many homeowners pay an architect twice after the commission rejected a design that didn’t match the original home’s brick or board-and-batten siding.
Home Addition Plans in Grapevine
Home Addition Plans in Grapevine are not a formality. If your lot sits inside the Historic District, the city wants drawings that match the original architectural style, down to matching brick or siding. We scope this before we quote. A standard room addition plan set for a 1970s or 1980s Grapevine home runs $2,800 to $6,500 depending on square footage and whether structural engineering is required.
Plans That Pass the First Review
We draw toward Grapevine’s actual requirements, not a generic template. That means checking the rear setback on lots under 7,200 square feet, confirming roof pitch compatibility in the Historic District, and noting drainage easements near Grapevine Lake. The goal is a permit that clears on the first submittal, because rejection letters add months and cost real money.
Field Notes Before the Estimate
Before we price your addition, we walk the lot. Flat terrain near the lake holds water after a storm, so we’ll recommend foundation elevation based on what we see. We also check the panel rating. Grapevine’s humid summers push HVAC loads hard, and an undercooled addition becomes a mold risk within one season.
In Law Suite Builders in Grapevine

In Law Suite Builders in Grapevine work under a specific rule. The city’s granny flat ordinance allows ADUs only on lots of 7,200 square feet or larger with rear yard setbacks, which pushes most projects to the 1970s and 1980s subdivisions north of Highway 114. A finished in-law suite in Grapevine typically runs $160,000 to $280,000 for a 500 to 800-square-foot build, including kitchenette, bath, and separate entrance.
Sizing the Suite to the Lot
An 8,000-square-foot lot north of Highway 114 can usually support a 600-square-foot detached ADU and still meet rear yard setbacks. A 6,500-square-foot lot in the central neighborhoods will not. We’ll tell you before you spend a dollar on plans whether your lot qualifies, because the ordinance is not negotiable.
Foundation and Drainage Work
Lots backing up to drainage swales near Grapevine Lake need elevated foundations, usually 12 to 18 inches above grade. That adds $4,000 to $9,000 to the build, but skipping it means water in the envelope after the first spring storm. We spec this before quoting so the written price reflects reality.
On ranch homes with limited panel capacity, the in-law suite typically needs a dedicated subpanel upgrade, usually to 200 amps. We include that line item in the written estimate rather than discovering it mid-job and re-pricing the project.
Trusted Brands We Service in Grapevine
We work with the prefab and modular platforms Grapevine homeowners are already researching. That includes Mighty Buildings and Boxabl for ADU shells, Plant Prefab for panelized room additions, and Tuff Shed-style structures for detached studio conversions. We also build conventional with James Hardie siding, which we match to original brick with painted trim details so the addition reads as one structure. If you’ve already priced a prefab unit, bring us the spec. We’ll tell you honestly whether it fits your Grapevine lot, what the site work will cost, and whether a conventional build makes more sense for your budget and setback.
Common Room Addition Contractor Problems We See in Grapevine Homes
- Historic District plan rejections. A homeowner draws an addition in a style that doesn’t match the original home’s brick or siding, the Preservation Commission rejects it, and now they’re paying for a second set of plans. We pre-check the guidelines before drawing anything.
- Undersized HVAC in humid summer conditions. Grapevine’s hot, humid climate turns an undercooled addition into a mold risk in one season. We size the HVAC load for the room’s actual square footage and the local humidity profile, not a national average.
- Setback violations on smaller lots. The 7,200-square-foot minimum for ADUs and rear yard setback rules are enforced. On smaller 1970s lots, a variance is possible but slow. We tell you where your lot stands before you commit to the project.
- Foundation settling near drainage swales. Flat terrain and proximity to Grapevine Lake mean water moves slowly after spring storms. We set foundations at the right elevation and grade the site so water moves away from the structure, not under it.
Pricing for Room Addition Contractor in Grapevine, TX
A standard room addition in Grapevine runs $180 to $320 per square foot before permit fees. A 400-square-foot addition lands between $72,000 and $128,000. Detached in-law suites run higher, usually $160,000 to $280,000 for a finished unit with kitchenette and bath. What moves the price: foundation elevation near drainage swales, Historic District siding matching requirements, HVAC upsizing for Grapevine’s humidity, and panel upgrades on older 1970s ranches. Our written price includes every one of those line items before you sign. Call (903) 342-8977 to schedule a free estimate, and we’ll scope the job in person, on your lot, with the actual conditions in front of us.
We Also Serve Cities Near Grapevine
Our crews serve Grapevine and the surrounding metro. If you’re in Coppell, Carrollton, Dallas, or Irving, we handle the same scope of work with the same written-price-first policy. Your project may fall under different municipal codes, so check with us for the specific requirements where you live. For Grapevine specifically, see our Grapevine page for more local detail.
Serving Grapevine, TX - Our Local Coverage Area
We’re based in the Grapevine 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 Grapevine
If your property sits outside Grapevine city limits but in the county’s jurisdiction, you’ll pull building permits through the county rather than the city, and you’ll also need to address septic and well setbacks that don’t apply inside city limits. County review typically moves slower than Grapevine’s permit desk, so plan for that in your timeline. Call (903) 342-8977 and we’ll confirm which jurisdiction applies to your address before you pay for drawings.
An 8,000-square-foot lot north of Highway 114 can typically support a second-story addition, but the structural review matters more than the lot size. 1970s ranch homes often have foundations rated for single-story loads, so you may need footing reinforcement before adding vertical load. We’ll bring a structural engineer’s review into the written price so you know the real number before committing.
On a well-and-septic lot near Grapevine Lake, your addition must maintain the county’s required setback from the septic tank, drain field, and well head, typically 10 to 25 feet depending on the system’s age and type. The county verifies this during permit review, and if your addition encroaches, you’ll be redrawn or the system gets relocated, which adds $8,000 to $25,000. We check the setback on the first site visit so it’s in the written price.
Adding a bathroom on a well system is allowed, but you’ll need to verify the existing pump and pressure tank can handle the added fixture count. Older wells serving 1970s ranch homes often have a 1/2 horsepower pump rated for two bathrooms; adding a third fixture group may require a pump upgrade, which runs $2,500 to $5,500 in the Grapevine area. We’ll check the pump spec and put the upgrade in the estimate if it’s needed.
Grapevine’s flat terrain and proximity to the lake mean water drains slowly after spring storms, even on property the flood maps don’t flag. An elevated foundation, typically 12 to 18 inches above grade, keeps standing water and storm runoff out of the floor assembly and prevents mold problems in the first wet season. We set the elevation based on what we see on your lot, not a flood-map default.
Written by Reed Calloway, Owner at Fielding ADU Dallas, serving Grapevine since 2006.









