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Get your free estimateHow Much Does Junior ADU & Interior Conversion Cost in Dallas?
In Dallas, a junior ADU or interior conversion typically runs $65,000 to $150,000 for a complete build, with garage conversions landing between $55,000 and $110,000 and attached wing conversions falling between $75,000 and $160,000 depending on finish level and site conditions. Those numbers include rough framing or demising work, plumbing, electrical, HVAC, insulation, drywall, flooring, and a basic kitchenette or bath where local code allows. Permit fees, architectural drawings, and engineering run another $4,500 to $12,000 on top in most Dallas neighborhoods.
Fielding ADU Builders puts the price in writing before any work starts, so the number you approve on day one is the number on the final invoice. If you want a straight answer for your specific lot, call (903) 342-8977 and we’ll walk the numbers with you directly.
Junior ADU & Interior Conversion Cost Breakdown (2026)
Here are the real line items we see across Dallas, from Lakewood to Oak Cliff to Richardson and north into Plano. These ranges reflect current labor, materials, and typical permit paths as of 2026.
| Line Item | Typical Dallas Range |
|---|---|
| Design & architectural drawings | $2,500 – $6,000 |
| Structural engineering | $1,200 – $3,500 |
| City of Dallas permit fees | $1,800 – $4,500 |
| Demolition & rough carpentry | $6,000 – $18,000 |
| Plumbing rough-in & fixtures | $7,000 – $20,000 |
| Electrical rough-in & panel work | $5,000 – $15,000 |
| HVAC mini-split or duct extension | $3,500 – $9,000 |
| Insulation & drywall | $4,000 – $10,000 |
| Flooring, trim, paint | $6,000 – $18,000 |
| Kitchenette | $8,000 – $25,000 |
| Bathroom (if included) | $12,000 – $35,000 |
| Total typical project | $65,000 – $150,000 |
A garage conversion in a neighborhood like Casa Linda or East Dallas usually lands at the lower end of that table, because the shell, slab, and roof are already there. An interior conversion that splits off part of a large single-family home, or adds a demising wall with its own entrance and utility drops, tends to run higher because the mechanical scope grows fast.
What drives a quote up: a second bathroom, a full kitchen instead of a kitchenette, relocating a water heater or panel, crawlspace or pier-and-beam foundation work, and any exterior door or window surgery on a brick veneer wall. Brick is everywhere in Dallas, and cutting a new opening in brick costs more than siding. What drives it down: keeping the existing bathroom, using a mini-split instead of extending ducts, and choosing a prefab platform like Cover or Abodu, which arrive with much of the interior already assembled.
What Affects Junior ADU & Interior Conversion Pricing in Dallas
- Lot and setback rules. Dallas has specific rear-yard coverage limits and setback requirements. If your lot is narrow or the existing structure already presses the line, you may need a setback variance, which is the city’s written permission to build closer to the property line than the standard rule allows. Variances add time and $1,000 to $3,000 in filing and hearing costs.
- Foundation condition. Dallas sits on expansive clay. Homes in older neighborhoods like M Streets, Junius Heights, and Winnetka Heights often need leveling or pier work before a conversion begins. If the slab or pier-and-beam has moved, the fix gets added to the quote before framing starts, and it is not optional.
- Panel capacity. A junior ADU needs dedicated circuits for a kitchenette, HVAC, and often a washer or mini water heater. If your panel is 100 amps and already full, a service upgrade runs $2,500 to $5,000 in Dallas, and the electrician has to coordinate with Oncor for disconnect and reconnect.
- Bathroom or no bathroom. This is the single biggest swing item. A half bath is one price. A full bath with a shower pan, tile, and a dedicated vent is another. In many Dallas conversions, adding a bath pushes the project past $120,000 quickly.
- Prefab versus conventional. We work with Abodu, Cover, Dvele, Mighty Buildings, Boxabl, and Plant Prefab, plus conventional builds using James Hardie siding and Tuff Shed-style structures. Prefab often shortens the schedule by 6 to 12 weeks and trims on-site labor, but the unit cost varies by platform and delivery radius into Dallas from their production facilities.
- Access and demolition. If the delivery path for a prefab unit or materials is tight, the crane or forklift cost rises. Older garages with asbestos-containing materials in the ceiling texture or floor tile add abatement fees. We see that most in mid-century homes across North Dallas and Richardson.
How to Save on Junior ADU & Interior Conversion
The fastest ways to bring a Dallas conversion in under $100,000 without cutting corners:
- Convert the garage first. You already own the shell, the slab, and the roof. That is $15,000 to $30,000 saved versus building a detached unit from the ground up.
- Keep it a junior ADU. A junior unit has a smaller footprint and fewer code triggers. No full second kitchen. No second gas line. Fewer meters to split.
- Use a prefab kitchenette and bath module. Platforms like Boxabl and Cover build these assemblies off-site with controlled costs. You pay one price instead of chasing five subcontractors.
- Do not move the plumbing. Locate the kitchenette or bath near the existing water and drain lines. Every foot of new underground waste line in Dallas clay soil adds excavation cost.
- Lock the scope before you start. Every change order after demo begins is where project costs leak. Fielding ADU Builders hands you a written price before any work starts, and we build to that number, not a moving target.
If you want a number for your specific garage or interior space, call (903) 342-8977. The estimate is free, and you will get real line items, not a ballpark.
FAQs – Junior ADU & Interior Conversion Cost
How much is a junior ADU in Dallas?
A junior ADU in Dallas costs $65,000 to $150,000 all-in for a permitted, finished unit as of 2026. The lower end assumes a garage conversion with a kitchenette and a half bath. The upper end is a larger attached interior conversion with a full kitchen and full bath. Call (903) 342-8977 for a written quote specific to your house.
Is it cheaper to convert a garage or build a detached ADU?
Converting a garage is cheaper in Dallas by $25,000 to $60,000 compared to a detached new-build ADU, because the slab, walls, and roof already exist. A typical garage conversion runs $55,000 to $110,000, while a detached unit starts around $120,000 and runs past $200,000 for a full-size two-bedroom. The trade-off is parking and storage, which some HOAs and buyers care about.
How long does a junior ADU conversion take in Dallas?
Plan on 4 to 7 months for a conventional interior or garage conversion in Dallas, including permits. Prefab platforms like Abodu and Cover can shorten the on-site portion to 8 to 12 weeks after the foundation and utility connections are ready. Permit review at the City of Dallas typically runs 4 to 8 weeks before work starts.
Do I need a permit for a junior ADU in Dallas?
Yes. Dallas requires building permits for any interior conversion that adds a dwelling unit, kitchenette, or separate living space. Unpermitted work creates problems at resale and can trigger a red-tag stop-work order mid-build. Fielding ADU Builders permits every project Junior ADU & Interior Conversion in Dallas the same way, by the book, with inspections passed and documented.
What is the cheapest way to add a rental unit to my Dallas home?
The cheapest permitted path is a junior ADU garage conversion, typically $55,000 to $85,000 with a kitchenette and half bath, no second gas line, and a mini-split for climate control. That number keeps you below the cost of a full detached ADU while still producing a legal, rentable unit. For an exact number on your property, call (903) 342-8977, and we will prepare a written estimate.
Why Fielding ADU Builders Writes the Price Down First
Reed Calloway runs Fielding ADU Dallas as an independently owned member of the Garrison Partners family, which has built to The Garrison Standard since 2006. That standard is not a slogan. It is five rules: show up in the window, price in writing, permit by the book, leave the site clean, and stand behind the work for a year.
Every project gets a 365-Day Done Right Promise in writing. If the work fails inside that year, we return and correct it at no charge. That includes a free second visit if something goes wrong after the final walkthrough. You are not calling a voicemail when a drywall crack appears or a mini-split throws a code. You call, a live person answers, and a uniformed, background-checked crew member is scheduled to come back. That has been how we operate since before the first ADU code update Dallas adopted, and it is how we operate now.
We also work fluently with the prefab platforms homeowners are already researching, which means we can match the method to the budget instead of forcing one construction style on every lot. Whether you want a Dvele panelized interior conversion, a Mighty Buildings unit, a Boxabl kitchenette module, or a conventional James Hardie build, we price it the same way: in writing, before any work starts.
Get a Written Price for Your Dallas Junior ADU or Interior Conversion
Call (903) 342-8977 and we will schedule a site visit, walk the space with you, and hand you a written estimate with real line items. No ranges from a website. No re-pricing at the door. The number you approve is the number on the final invoice, backed by a one-year written guarantee.
If you are still comparing options, start with our home page to see the full scope of what we build. Then call. The estimate costs you nothing, and you will leave the conversation knowing exactly what your project costs in Dallas right now.
Pricing reflects the Dallas market as of 2026. Written by Reed Calloway, owner at Fielding ADU Dallas, serving Dallas since 2006. Fielding ADU Dallas offers free estimates – call (903) 342-8977.
What Our Customers Say
"Garage conversion with a new bath and kitchenette. Permit was handled by them. Inspection passed first time."
- Sheila B."Built a detached ADU behind our house. The builder is a veteran and runs the site like a platoon: schedule posted, crew on time, everything labeled. Finished within a few days of the date."
- Ken W."Room addition over the back patio. Framing is square, windows are tight, and the roofline matches."
- Danny L.
