Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Fast, Reliable Home Additions & ADU Across Midlothian
Adding square footage to a Midlothian home means building on Blackland Prairie clay that moves more than most soils in Texas, and that changes how foundations, site prep, and drainage need to be handled. A room addition in Midlothian typically runs $45,000 to $130,000, while a detached ADU built to current Ellis County code usually lands between $90,000 and $220,000 depending on size, foundation engineering, and utility runs. Barrett & Sons Construction has been building in this soil since 1998, and we know which foundation details keep an addition from cracking ten years out. Call (877) 610-1318 and Tom or one of his sons will walk you through what your specific lot needs before you spend a dime.
Why Barrett & Sons Construction Is Midlothian’s Preferred Home Additions & ADU Company
Tom Barrett puts his name, his address, and his license number on every page and every contract, and Midlothian homeowners have learned to look that up before signing anything. We are not a franchise dispatching strangers from another state. Tom lives close enough that he will see you at the grocery store, and his sons run the crews that show up at your house. That changes how we build.
Midlothian customers call us because the last contractor they used told them a permit was optional. Around here, the permit inspector works for you, not for me, and we pull permits and get inspections signed on every eligible job. We also write every scope, every allowance, and every price change as a written change order before work proceeds. If it is not on paper, it is a surprise waiting for a date, and we do not do surprises.
Every completed job carries our written 90-Day Done Right Promise. If something is not right, one call brings Tom back to make it right. We also publish four standing offers: $40 off any repair over $200, a free second opinion on any written estimate, no trip charge inside Ellis County, and a permanent 10% discount for seniors and veterans. A live person answers our phone 24 hours a day, seven days a week.
Our Home Additions & ADU Services in Midlothian
When you decide to build an addition or an ADU in Midlothian, the first real question is not what it costs. It is whether the company quoting you understands what happens to a slab on this soil. Here is how we approach the four most common projects.
ADU Design & Permitting
A detached ADU in Midlothian is a full second dwelling, and Ellis County treats it that way. We handle design, structural engineering, permit submittal, and the inspections that follow. The city’s zoning for ADUs is specific, and we have walked enough Midlothian lots to know which setbacks and utility easements will shape what you can build. Getting this right before the first trench is dug is the difference between a smooth build and a stop-work order.
Garage Conversion ADU
Converting an attached garage into a rental unit or in-law suite is one of the most cost-effective ways to add living space in Midlothian, where garages on 2000s-era slab homes are already built to house weight. A garage conversion in Midlothian typically runs $30,000 to $80,000 depending on whether you need a kitchenette, a full bath, and a separate entrance. The foundation is already there, but drainage and moisture control still need attention on this clay.
New Detached ADU
Building a new detached ADU in Midlothian means starting from scratch on soil that can shift two to four inches between a wet spring and an August drought. That is why we spec post-tension or engineered foundations as standard on these builds, and why we pay attention to site drainage and moisture barriers before the concrete goes down. A new detached ADU in Midlothian runs $90,000 to $220,000 for a complete, code-passing unit.
Junior ADU & Interior Conversion
A junior ADU converts part of your existing home, like a finished basement space, a large bonus room, or an attached wing, into a semi-independent living area with its own entry and modest kitchen facilities. This is often the most affordable route in Midlothian because you are working inside an existing envelope. We still permit it as a conversion, and we still write every change order in full before any wall opens.
If you are also looking at Kitchen Remodeling in Midlothian or Bathroom Remodeling in Midlothian as part of the same addition, we will coordinate the trades so your family is not living through two separate demolition cycles.
Trusted Brands We Service in Midlothian
We carry premium-brand depth across every trade we touch, because Midlothian homeowners should be able to look up the materials on their own and verify what they are paying for. On additions and ADUs we regularly install GAF roofing systems, Schluter waterproofing in baths and utility areas, and Grohe fixtures where plumbing is part of the scope. We stock common replacement parts locally for Midlothian jobs so smaller fixes do not wait on a slow supply chain. The brands are not mystery names off a van; they are ones you can research before you sign.
Common Home Additions & ADU Problems We See in Midlothian Homes
Midlothian’s building boom means most homes are newer, but newer is not the same as problem-free. Here is what we run into most often when we start an addition or ADU project on this side of Ellis County:
- Slab settlement and cracking from Vertisol clay. Black gumbo soil swells in wet springs and contracts hard in summer, and a slab that was not engineered for that movement will telegraph cracks into any new structure tied to it. We inspect the existing foundation before we design anything.
- Drainage problems on flat, post-2000 lots. Many Midlothian lots were graded quickly during the DFW housing push south, and water pools near the slab line after heavy rain. An addition built without addressing drainage first will inherit that problem.
- Additions that were never permitted. We see a lot of previous contractor work around Midlothian that has no permit record, which complicates any future sale or insurance claim. Our work is permitted and inspected, every time.
- Cheap mix designs from out-of-town builders. Midlothian crews know the local cement plants and the sulfate-bearing clay that eats standard DFW concrete over time. Out-of-town builders who bring a generic mix design often see premature slab cracking within a few years. We spec concrete calibrated for Ellis County soil.
Pricing for Home Additions & ADU in Midlothian, TX
A home addition in Midlothian runs $45,000 to $130,000, and a detached ADU runs $90,000 to $220,000. A garage conversion sits between $30,000 and $80,000 depending on whether you are adding a bath and kitchenette or just framing out living space. What moves the number most in Midlothian is foundation engineering: your lot’s soil report, the drainage plan, and whether the existing slab can carry the new load without an engineered retro-fit. We give you a written line-item quote before work starts, and we never change the price without a written change order you have signed first. Call (877) 610-1318 to schedule a free estimate; we will walk the lot with you and tell you straight what your project should cost.
Key Takeaways
- Home additions in Midlothian typically run $45,000-$130,000; ADUs run $90,000-$220,000; garage conversions run $30,000-$80,000.
- Midlothian’s Vertisol clay soil demands engineered foundations and careful drainage work; this is not optional on most lots.
- Tom Barrett is on-site most days, and his sons run the crews; permits are pulled and inspections are signed on every eligible job.
- Every scope and allowance is written, every change order is signed before work proceeds, and every job carries the 90-Day Done Right Promise.
We Also Serve Cities Near Midlothian
Our crews work throughout southern Dallas and northern Ellis County. In addition to Midlothian, we regularly build home additions and ADUs in Cedar Hill, Mansfield, Glenn Heights, and Red Oak. If you are just outside the city line, call (877) 610-1318 and ask whether the no-trip-charge area covers your address.
Serving Midlothian, TX - Our Local Coverage Area
We’re based in the Midlothian 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 Midlothian
We can usually have a site visit scheduled within a few business days of your call, and the design and permitting phase is what sets the real timeline. In Midlothian, that often runs four to eight weeks depending on the city’s current review queue. We do not promise same-day starts on planned construction; we promise an honest schedule and a permit that will pass inspection. Call (877) 610-1318 to get on our schedule.
We cover all of Midlothian’s 76065 ZIP code, including newer neighborhoods along 9th Street near Heritage High School, communities east of Business 287, and the growing subdivisions north of the cement plants toward the Trinity River. The major roads we run most are U.S. 287, East Main Street, and 9th Street. If you are not sure whether your street is in our service area, call and ask; chances are we have already built on a block near you.
Yes, often slightly more, and the reason is the soil. Midlothian’s Blackland Prairie clay requires more extensive foundation engineering than the sandier soils you find in parts of Mansfield or Johnson County to the west. The cement plants here supply local ready-mix calibrated for Ellis County sulfate-bearing clay, and that adds real material and labor cost. A detached ADU in Midlothian runs $90,000 to $220,000, and an out-of-town builder who quotes far less is usually skipping the soil work. Call (877) 610-1318 for an exact quote; estimates are free.
Every job Barrett & Sons completes carries our written 90-Day Done Right Promise. If something is not done right, one call brings Tom Barrett back to fix it. Beyond that, we stand behind the materials from brands like GAF and Schluter, and all permitted work carries the full inspection record the city holds. If a problem shows up, we want to know about it; we live close enough to see you at the hardware store.
Yes, on every eligible job, no exceptions. We pull the permits, schedule the inspections, and get them signed before we call the job done. The permit inspector in Midlothian works for you, not for the contractor, and a builder who tells you permits are optional is telling you he is willing to hide work from the city. That is not how we build. Call (877) 610-1318 to schedule a free estimate and see our permit records for past Midlothian jobs.
Ready to Add Space to Your Midlothian Home?
Whether you are adding a second story, a detached ADU for rental income or family, or converting a garage into a suite, the first step is a conversation with someone who knows Midlothian’s soil, codes, and neighborhoods. Call Barrett & Sons Construction at (877) 610-1318 today. We will walk your lot, write you a line-item estimate, and tell you straight what your project should cost. Free estimates, no trip charge inside Ellis County, and the 90-Day Done Right Promise in writing on every contract.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Midlothian since 1998.







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