Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterFast, Reliable Home Additions & ADU Across Keller
A home addition in Keller runs $45,000 to $130,000 for most room additions, while a detached ADU typically lands between $90,000 and $220,000 and a garage conversion falls in the $30,000 to $80,000 range. Those are real numbers from Keller’s market, and they’re what you should expect before anyone starts talking allowances. We’re Barrett & Sons Construction, and we’ve been building, remodeling, and adding space for homeowners since 1998, with Tom Barrett’s name on the truck and his sons running the crews. If you’re planning an addition or ADU in Keller, call (877) 610-1318 and we’ll walk the lot with you before we ever put a number on paper.
Why Barrett & Sons Construction Is Keller’s Preferred Home Additions & ADU Company
Keller homeowners call us because we don’t send a sales rep to the door and a stranger to the job. Tom Barrett and his sons are on-site most days, and that changes how a project runs. In Keller’s established neighborhoods, where brick-veneer homes are aging in near-lockstep and HOAs watch every exterior change, you need a contractor who knows what the city’s inspectors will flag and what the HOA board will reject before week one, not after.
We pull permits and get inspections signed on every eligible job. That matters more in Keller than most places, because cutting into a post-tension slab without marking tendons can snap a cable and void a foundation warranty. We’ve watched competitors skip that step to save a day and cost a homeowner six figures. We walk the perimeter first, check for differential settlement, and put the scope in writing before a single nail moves. The permit inspector works for you, not for us, and we like having him on the job.
Our Home Additions & ADU team serves Keller from the Dallas-Fort Worth area, and we know the zip codes, the HOA boards, and the clay soil. Every price change arrives as a written change order before work proceeds. Every scope, every allowance, every line item goes on paper. An allowance that isn’t on paper is a surprise waiting for a date.
Our Home Additions & ADU Services in Keller
ADU Design & Permitting
Building an ADU in Keller starts with the foundation. The city sits on expansive clay that shrinks in North Texas summers and heaves after rain, so we begin every ADU design with a foundation-specific site inspection. We’ll identify any differential settlement in your post-tension slab, mark the tendons before any concrete is cut, and design a load-bearing plan that accounts for shrink-swell movement. Then we handle the permit package, HOA submittal, and inspection scheduling so you’re not standing at the city counter trying to decode a form.
Garage Conversion ADU
A garage conversion in Keller typically runs $30,000 to $80,000, and it’s often the fastest path to rental income or multi-generational living. But here’s what a cheap quote leaves out: wind-rated tie-downs, insulation that meets Keller’s energy code, and the structural work needed when a garage slab was never meant to carry living-space loads. We convert garages with the same permitting and inspection rigor we’d use on a ground-up addition, and every change order stays in writing.
New Detached ADU
Detached ADUs in Keller run $90,000 to $220,000 depending on square footage, finishes, and foundation needs. The soil here is the deciding factor on cost: a lot in Woodland Springs may need helical piers or deeper footings where the clay has moved over two decades. We quote that honestly up front, not after we’ve dug the hole. You’ll get a line-item estimate showing foundation work, framing, roofing, electrical, plumbing, and finishes, with named brands like GAF on the roof rather than whatever fell off the truck.
Junior ADU & Interior Conversion
A junior ADU, typically a converted interior space with a separate entrance, kitchenette, and bath, runs lower than a detached build because you’re working within existing walls. In Keller homes built between 1995 and 2008, we commonly find that the existing mechanicals, water heater, and panel have enough remaining life to support the added square footage without replacement. We’ll verify that during the planning phase before you commit to a budget. If the scope changes, the change order comes in writing.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Keller
We install materials you can look up, not mystery brands off a van. On Keller additions and ADUs we use GAF roofing systems because they carry the wind ratings the DFW hail corridor demands, Schluter waterproofing in wet areas, and Sterling or Grohe fixtures where the job calls for them. When you see a GAF shingle spec on your Keller roof, you can verify the wind rating yourself. A compliant quote names the brand and the model so you can look it up before you sign anything.
Common Home Additions & ADU Problems We See in Keller Homes
- Cutting into a post-tension slab without marking tendons. Keller’s post-tension slabs carry steel cables under tension. Unmarked cutting can snap a cable, blow out the slab edge, and void the foundation warranty. We mark and map every tendon before any saw touches concrete.
- Vague allowances on cheap bids. A Keller addition quote that says “allowance: plumbing” with no dollar figure attached is not a quote. We write every allowance in dollars and every change as a written change order before work proceeds.
- Missing wind-rated tie-downs. Keller sits in the DFW hail corridor, and spring storms produce real uplift force on new roofs. A compliant addition needs wind-rated straps and anchors engineered to current code. Cheap quotes omit them because they add a day and materials; insurance finds out later.
- HOA stop-work orders. Most Keller additions need HOA approval for exterior materials, colors, and setbacks. Starting without it triggers a stop-work order and a change order to match the approved brick veneer. We file the HOA package before we pull the permit.
Pricing for Home Additions & ADU in Keller, TX
| Project Type | Typical Keller Range |
|---|---|
| Home Addition | $45,000-$130,000 |
| ADU Construction | $90,000-$220,000 |
| Garage Conversion | $30,000-$80,000 |
What moves the number most in Keller is the soil. Expansive clay means some lots need helical piers or deeper footings, and a foundation-specific site inspection is the only way to know before you’re committed. We give free estimates, and every estimate is a written, line-item scope so you can compare it line by line against any other bid. Call (877) 610-1318 and Tom or one of his sons will come out, walk the property, and put a real number in front of you.
We Also Serve Cities Near Keller
If your project is just outside Keller, we serve Watauga, North Richland Hills, Roanoke, and Saginaw as well. The same crews, same written change orders, and the same 90-Day Done Right Promise apply across the area. Take a look at our Keller page for this city specifically, or visit our Home Additions & ADU service hub for the full scope of what we build.
Serving Keller, TX - Our Local Coverage Area
We’re based in the Keller 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 Keller
What wind-load rating does a Keller home addition need to meet under current code?
A Keller home addition must meet the wind-load requirements of the current International Residential Code with Texas amendments, which for Keller’s wind zone means engineered tie-downs, straps, and anchors from roof to foundation. The exact design wind speed your architect or engineer specifies depends on the structure’s exposure, but the point is that a compliant quote in Keller includes those connections by name and by count. If your quote doesn’t mention wind-rated tie-downs, ask why, then call (877) 610-1318 for a second estimate that does.
Do I need a permit for a garage conversion ADU in Keller, and what inspections are involved?
Yes, a garage conversion ADU in Keller requires a building permit, and inspections include foundation and slab, framing, electrical rough-in, plumbing rough-in, insulation, and final. If you’re modifying the slab or adding plumbing, you’ll also need the relevant trade permits. We pull all permits and schedule every inspection, and we don’t close a wall until the inspector has signed off. The inspector works for you, not for us, and we like him there.
How does documented wind-storm compliance help my insurance after a hail event?
Documented wind-storm compliance means your file shows the roof and structure were built to current wind-load code with inspections signed, which is exactly what an adjuster asks for after a hail claim. A Keller addition with wind-rated tie-downs, a GAF roof with verifiable specs, and a paper trail of permit sign-offs holds up better to a claim than a structure with no documentation. We hand you the full file at close-out so you can forward it to your carrier.
Can I build a detached ADU on a post-tension slab lot in Keller?
Yes, you can build a detached ADU on a post-tension slab lot in Keller, but you must not cut into the existing slab without first marking and mapping the tendons. A snapped tendon can void your foundation warranty and cost tens of thousands to repair. The new ADU foundation is typically a separate pour with its own footings, and on Keller’s clay we often add helical piers where soil movement has been documented. We do the site inspection and foundation design before any concrete is touched.
What does a compliant Keller addition quote include that a cheap one leaves out?
A compliant Keller addition quote includes a foundation-specific site inspection, a load-bearing plan for shrink-swell clay movement, wind-rated tie-downs engineered to current code, named material brands with verifiable specs, permit costs, and inspection scheduling. A cheap one leaves out the tie-downs, uses “allowances” without dollar figures, and skips the HOA package. If the difference isn’t on paper, it isn’t in the quote. Call (877) 610-1318 and we’ll put ours in writing so you can compare line by line.
How long will my Keller home addition take, and will the price change once work starts?
A room addition in Keller typically runs eight to sixteen weeks depending on foundation work, HOA timing, and inspection scheduling. A detached ADU runs longer, often four to seven months. The price changes only if the scope changes, and every change arrives as a written change order before work proceeds. That’s not a promise we make lightly; it’s how Tom has run the company since 1998.
Call Barrett & Sons Construction for Your Keller Addition or ADU
If you’re planning a home addition, garage conversion, or ADU in Keller, start with a contractor who will walk the slab, check the soil movement, pull the permits, and write every scope and allowance down before a nail moves. Tom Barrett publishes his name, his address, and his license number. Look it up before you sign anything. Then call (877) 610-1318 for your free estimate. We’ll walk the lot, answer your questions, and put a real number in front of you in writing.
Written by Tom Barrett, Owner at Barrett & Sons Construction, founded 1998 and serving Keller, TX home additions and ADU projects with permits pulled, inspections signed, and every change order in writing.