ADU in Arlington, TX
ADU design and permitting in Arlington, TX typically costs $8,000-$22,000 for the design, permit set, and city approvals before construction begins, and the work is driven by two local realities: 1960s-1980s ranch homes on black clay soil, and a zoning code that is stricter than either Dallas or Fort Worth. Most Arlington ADU projects start with a garage conversion or detached backyard cottage on lots large enough to hold them, but the original 100-amp electrical service and irregular rear setbacks in older platted neighborhoods create permitting hurdles that an engineer familiar with Arlington’s rules resolves before the first excavation. Call (971) 497-2402 and we’ll give you a written price for design through final inspection, not a range that drifts.
Why Arlington Homes Are Different
Arlington sits on Blackland Prairie expansive clay, the same shrink-swell soil that cracks driveways and shifts slabs across the Metroplex. A detached ADU on this ground cannot sit on a standard slab; it needs engineered piers or a post-tension slab designed for the movement, which adds $8,000-$20,000 to the project before framing starts. The 1960s-1980s housing stock throughout neighborhoods like Dalworthington Gardens, Pantego, and the subdivisions east of Cooper Street runs on 100-amp electrical panels, and every ADU permit in Arlington requires enough remaining capacity for the new unit. That almost always means a panel upgrade, scoped and priced before the permit set goes in.
Summer heat indexes above 105°F are not a seasonal anomaly here, they’re a design constraint. A detached ADU in Arlington needs HVAC sizing and attic insulation engineered to a higher standard than the parent home’s original 1980s-era code required, which changes both the mechanical design and the roof framing. Add Arlington’s position between Dallas and Fort Worth, both of which have liberalized their ADU ordinances while Arlington’s own code remains one of the more restrictive in the region for accessory structures, and you get a market where the difference between approval and a denied permit is often a setback-variance calculation done right the first time.
Our Main Arlington Services
Two ADU paths dominate in Arlington: converting the attached garage that already sits under your roof line, or building a detached unit in the backyard where the lot allows. Both start with the same written price and permit set.
Garage Conversion ADU in Arlington
Most Arlington ranch homes built between 1960 and 1985 have attached one- or two-car garages with concrete slabs already in place, which makes them the most cost-efficient ADU path in the city. The catch is Arlington’s zoning: the city requires that a garage conversion either preserve covered parking or replace it elsewhere on the lot, a rule that kills many projects when the driveway geometry does not cooperate. We run the parking analysis during the site assessment and tell you whether your garage converts or whether a detached build makes more sense. Garage Conversion ADU in Arlington gets the full scope.
New Detached ADU in Arlington
Arlington lot sizes in the 1960s-1980s subdivisions are generous enough to hold a backyard cottage in many cases, but the black clay soil and irregular rear setbacks in older platted neighborhoods complicate siting. A detached ADU here is typically a 600-1,200 square foot structure on an engineered foundation, with HVAC sized for 105°F summers and the 100-amp panel addressed before framing. New Detached ADU in Arlington covers foundation, framing, mechanicals, and the written price for the full project.
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.
ADU Design & Permitting in Arlington
ADU design and permitting in Arlington is the stage where a project either clears the city’s restrictive accessory-structure rules or stalls for six months on a variance nobody filed. The 1960s-1980s ranch stock, the 100-amp electrical standard of that era, and the shrink-swell clay under every slab all feed into the permit set. Our ADU Design & Permitting service produces drawings, structural calculations, energy compliance documentation, and the permit application as one package with one written price, per Haven Standard Clause 1.
Site Assessment
Signs you need it
You are weighing a garage conversion against a detached unit and do not know whether Arlington’s parking-replacement rule or your rear setback kills one of the options.
What it costs in Arlington
Site assessments in Arlington run $500-$2,000 depending on lot complexity and whether soil testing is required.
How we do it
We measure the lot, verify the setbacks against Arlington’s zoning code, test the soil for shrink-swell behavior, document the current electrical service, and return a written siting report that says which ADU path is buildable and why.
ADU Design & Blueprints
Signs you need it
You have a floor plan in your head but no permit-ready drawings that account for Arlington’s lot coverage rules, energy code, and the structural demands of clay soil.
What it costs in Arlington
Full ADU design and blueprint sets in Arlington run $4,000-$12,000 depending on unit size and whether the project is a conversion or a new detached structure.
How we do it
We draft the architectural set, size the HVAC to Arlington’s summer heat loads, size the structure to the soil report, and produce the permit set that goes to the city, not a concept sketch.
Permit Application
Signs you need it
You have drawings from another designer but the city bounced the application back for a setback detail, a parking issue, or an electrical-load question nobody caught.
What it costs in Arlington
Permit application and city coordination in Arlington run $3,000-$8,000 including the city’s filing fees and our response to review comments.
How we do it
We submit the full permit set, track the review, answer every city comment in writing, and do not stop until the permit is issued and the inspection schedule is confirmed.
HOA & Zoning Compliance
Signs you need it
Your Arlington neighborhood has a homeowners association with rules that conflict with, or add to, the city’s accessory-structure ordinance, and you need both layers cleared before construction.
What it costs in Arlington
HOA and zoning compliance review in Arlington runs $500-$2,000 when bundled with the permit application.
How we do it
We pull the HOA covenants, map them against the city zoning code, and document every compliance item in the permit set so no board or inspector is surprised later.
What ADU Design & Permitting Costs in Arlington
| Item | Typical range in Arlington |
|---|---|
| Site Assessment | $500-$2,000 |
| ADU Design & Blueprints | $4,000-$12,000 |
| Permit Application & City Coordination | $3,000-$8,000 |
The Arlington-specific costs are the clay-soil foundation engineering and the parking-replacement analysis on garage conversions. Both are quoted in writing before any design work starts.
How long does ADU design and permitting take in Arlington?
Plan on 3-6 months from site assessment to issued permit in Arlington, with the city’s review speed and any setback variances being the main variables. We submit complete permit sets to avoid the review-comment loops that stretch timelines.
Will the design price change once the project starts?
No. The design and permitting price is written before work begins, per Haven Standard Clause 1. If the city requires a revision, we price it in writing before doing the work. Call (971) 497-2402 to get your scope documented.
Junior ADU & Interior Conversion in Arlington
A junior ADU or interior conversion in Arlington takes square footage you already own, usually a bedroom wing, a bonus room, or space over an attached garage, and converts it into a permitted second unit. The appeal here is simple: no new foundation on black clay, no new setback fight, and a much shorter permit path than a detached build. Our Junior ADU & Interior Conversion service covers the conversion, the required egress work, the separate entrance, and the electrical separation, all under one written price.
Room-to-ADU Conversion
Signs you need it
You have an unused bedroom wing or bonus room with an exterior wall where a separate entrance can go, and you want a permitted unit without adding foundation work or new square footage.
What it costs in Arlington
Room-to-ADU conversions in Arlington run $60,000-$120,000 all-in, depending on whether the existing bath and kitchenette can be reused or must be built out.
How we do it
We confirm the egress windows and separate entrance against Arlington’s code, separate the electrical and HVAC zones, add the required kitchenette and bath, and document every step with the photo record.
Above-Garage ADU
Signs you need it
Your two-story home has bonus space above the garage that sits empty, and you want to convert it into a rentable unit with its own access.
What it costs in Arlington
Above-garage ADU conversions in Arlington run $80,000-$160,000, with the higher end reflecting the structural reinforcement and stair access these projects almost always require.
How we do it
We verify the floor structure will carry the new unit, add the separate entrance with proper fire separation, size the HVAC for the upstairs heat load, and design the electrical separation for a second meter.
What Junior ADU & Interior Conversion Costs in Arlington
| Item | Typical range in Arlington |
|---|---|
| Room-to-ADU Conversion | $60,000-$120,000 |
| Above-Garage ADU | $80,000-$160,000 |
| Interior JADU (with existing bath reuse) | $50,000-$90,000 |
Interior conversions avoid Arlington’s clay-soil foundation costs entirely, which is why they price below detached builds. The tradeoff is that the unit size is fixed by the existing footprint.
Do interior ADU conversions in Arlington need a separate entrance?
Yes. Arlington code requires a junior ADU or interior conversion to have its own exterior entrance or a clearly separated interior access. That door, its fire rating, and its egress path are in the permit set.
Can I rent a junior ADU on a short-term basis near AT&T Stadium?
Arlington’s event-driven rental market near the stadium makes short-term rental income a real motivator, but rental use rules vary by zoning district and HOA. We document the rental-use constraints for your specific lot during the site assessment. Call (971) 497-2402 for the written scope.
ADU Site Prep & Utilities in Arlington
Site prep and utilities in Arlington is where the black clay soil and the 100-amp panel standard collide with the reality of building a second unit. The foundation has to be engineered for shrink-swell movement, the electrical service has to be upgraded before the city issues the permit, and the trench work for water, sewer, and gas has to be coordinated so you dig once. Our ADU Site Prep & Utilities service covers everything from the first soil test to the final utility connection, with a written price and a documented photo record on every visit.
Foundation & Grading
Signs you need it
Your lot sits on Arlington’s expansive clay and any detached ADU needs engineered piers or a post-tension slab, plus grading that drains the site correctly during the region’s heavy-rain swings.
What it costs in Arlington
Foundation and grading for a detached ADU in Arlington run $8,000-$25,000 depending on soil test results, pier depth, and whether your lot needs any cut-and-fill work.
How we do it
We take soil borings, have the structural engineer design the pier or post-tension system to the soil report, grade the site for positive drainage, and document the foundation before concrete is poured.
Electrical Panel Upgrade
Signs you need it
Your Arlington home has the original 100-amp service from the 1960s-1980s era, and the new ADU’s load calculation shows there is not enough capacity left for a second unit.
What it costs in Arlington
Panel upgrades in Arlington run $3,000-$8,000 depending on whether you need a 150-amp or 200-amp service and how far the meter is from the panel.
How we do it
We run the load calculation required by Arlington’s permit office, specify the new panel size, coordinate the utility disconnect, and document the final inspection sticker.
What ADU Site Prep & Utilities Costs in Arlington
| Item | Typical range in Arlington |
|---|---|
| Foundation & Grading | $8,000-$25,000 |
| Electrical Panel Upgrade | $3,000-$8,000 |
| Plumbing & Utility Trenching | $5,000-$15,000 |
The soil is the main Arlington variable on foundation cost. The panel upgrade is nearly universal on 1960s-1980s homes. Both are quoted in writing before any dirt moves.
Does Arlington require a soil test before a detached ADU?
Yes, in practice. The city’s building department will not approve a detached ADU foundation without an engineered design, and the engineer needs a soil report to design for the Blackland Prairie’s shrink-swell clay.
Can I keep my existing panel and just add a subpanel for the ADU?
Sometimes, if the existing service has enough remaining amperage after the load calculation. A 100-amp panel almost never does once the ADU’s HVAC and appliances are added. We price both paths before you commit. Call (971) 497-2402 for the written line items.
Brands We Service in Arlington
We specify and coordinate prefab systems from Abodu, Cover, and Dvele for Arlington lots where a factory-built unit beats stick framing on cost or schedule. Components and finish materials are ordered locally through our supply partners, which shortens lead times. See our brands for the full list.
Pricing for ADU in Arlington, TX
| Service | Typical range in Arlington |
|---|---|
| Garage Conversion ADU | $65,000-$130,000 |
| New Detached ADU | $180,000-$350,000 |
| Site Assessment | $500-$2,000 |
| ADU Design & Blueprints | $4,000-$12,000 |
| Permit Application & City Coordination | $3,000-$8,000 |
| Room-to-ADU Conversion | $60,000-$120,000 |
| Above-Garage ADU | $80,000-$160,000 |
| Foundation & Grading | $8,000-$25,000 |
| Electrical Panel Upgrade | $3,000-$8,000 |
| Plumbing & Utility Trenching | $5,000-$15,000 |
The two things that push a price up in Arlington are the clay-soil foundation engineering on detached builds and the parking-replacement rule on garage conversions. Whatever the number is on your project, it is written before any work starts, per Haven Standard Clause 1. You will never hear “call for a quote” from us; you get a line-item price.
Neighborhoods We Serve in Arlington
We work across Arlington’s residential footprint, from the established ranch-home subdivisions east of Cooper Street to the platted lots near Lake Arlington and the neighborhoods bordering Pantego and Dalworthington Gardens. Most sites are within a 20-30 minute drive of our Dallas-Fort Worth office, and we schedule site assessments in Arlington within one business week of the first call.
- Dalworthington Gardens
- Pantego
- West Arlington
- North Arlington
- East Arlington
Service Area - Cities Near Arlington
In addition to Arlington, we serve the surrounding Metroplex communities where homeowners face the same black-clay soil and 100-amp panel realities. Our crews work in Mansfield, TX, Burleson, TX, Cedar Hill, TX, and Grand Prairie, TX, with the same written-price guarantee on every project.
Serving Arlington, TX - Our Local Coverage Area
We’re based in the Arlington 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 in Arlington
Yes. Because dispatch is coordinated from our Dallas-Fort Worth office and crews serve Arlington locally, we schedule site assessments in Arlington within one business week. The assessment is written into the design price, not an add-on.
It depends on your specific subdivision’s covenants. Many Arlington neighborhoods have active HOAs that add rules on top of the city’s zoning code. We pull the HOA documents during the zoning-compliance review and map every restriction against the permit set so nothing is missed.
Will the price change once construction starts in Arlington?
No. Every ADU project in Arlington is governed by The Haven Standard: a written price before work starts, a documented photo record on every visit, and the 365-Day Done Right Promise in writing. Scope is locked at signing; no change orders without a written amendment. Call (971) 497-2402 to schedule your free estimate and get your Arlington project documented.
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 Arlington Customers Say
"They walked us through setbacks and utility capacity before we paid anything, and told us one of our two options was not going to get approved."
- Mireille T."Every allowance was itemised at the start, so the finish selections did not turn into a surprise at the end."
- Benedict H."Handled the whole planning process. We went to one hearing and that was it."
- Rowena C.