Fast, Reliable New Detached ADU Across Colleyville
A new detached ADU in Colleyville typically costs $285,000 to $410,000 all-in, from the first survey through final inspection, and the permitting path runs through your HOA before it ever reaches City Hall. Colleyville’s estate lots and detached garage stock make it one of the few DFW suburbs where an ADU is usually a conversion or a second-story build over an existing structure, not a ground-up tear. We coordinate the covenant review, the engineered foundation, the custom millwork, and the permit set under one contract and one written price. Call (971) 497-2402 and we’ll walk you through what your specific lot will actually require.
Why Ellery ADU Studio Is Colleyville’s Preferred New Detached ADU Company
The team at Ellery ADU Studio has designed, permitted, and built 900+ ADUs since 2015, and the Colleyville projects share a pattern most contractors miss: the city will approve a lot that the HOA won’t. We treat the covenant review as Step Zero, because in Colleyville it is. Nadia Ellery founded the studio around the permit set as the core product, and that’s exactly what a Colleyville detached ADU needs – a set of drawings engineered for Blackland Prairie clay, reviewed by an architectural committee that compares fascia to fascia.
Colleyville homeowners tell us the same three things again and again. They want the price on the page, not a callback. They want to know the HOA amendment path before they spend money on a survey. And they want documentation – the photo record, the written scope, the warranty language – not a verbal promise. We deliver all three, every time. Our one-contract design-build model means neither a designer nor a builder can point at the other when a submittal gets rejected. Under Haven Standard Clause 1, the price is written before any work starts, and under Clause 5, the scope is locked at signing. No door-side upsells, no scope creep.
We work in Colleyville’s neighborhoods from Montclair Parc to the gated enclaves west of Bransford Road, and our crews have sat in enough ARB hearings to know which details trigger a rejection. Matching original brick coursing matters. Roof pitch matters. The species of cedar on the garage door header matters. That’s the work we do before the permit application is even filed, and it’s why our Colleyville clients don’t get surprised mid-frame.
Our New Detached ADU Services in Colleyville
Custom Built ADU
A custom detached ADU in Colleyville runs $310,000 to $410,000 when it’s built over or beside an existing structure, and the line items that move that number are foundation engineering and architectural submittals, not framing labor. On a 22,000-square-foot lot in a 1990s subdivision, you’re matching brick, mortar color, roofline, and trim detail to a house that was custom-built thirty years ago. We coordinate that match as part of the permit set, so the HOA review has something concrete to approve. Custom cabinetry, architectural glass, and millwork are ordered early, with submittals submitted before the slab is poured.
Studio ADU
A studio ADU in Colleyville typically runs $285,000 to $340,000 and is the most common configuration we build over detached three-car garages. The appeal is obvious: the footprint already exists, the structure is already there, and the city sees it as accessory. The HOA may not. We run the covenant check first, then engineer the post-tension slab, then lock the full material schedule in writing. For a studio over a garage, the long-lead items are custom windows and the staircase – both of which we order the week the permit set is approved, not the week framing starts.
Prefab ADU Installation
Prefab and modular systems from Abodu, Cover, and Dvele can cut Colleyville construction time by two to four months, but the site work doesn’t shorten. The Blackland Prairie clay still requires the same engineered foundation, and the HOA still reviews the exterior elevation against the main house. We specify the prefab system and coordinate it within the same single contract – one written price covers the factory order, the site prep, the crane, the finishes, and the final inspection. That’s the part most installers leave out of their quote, and it’s the part that blows budgets.
1-Bed & 2-Bed ADU
A one-bedroom detached ADU in Colleyville runs $295,000 to $355,000; a two-bedroom runs $330,000 to $410,000. The price difference is real but smaller than most homeowners expect, because the foundation, the HOA review, the architectural match, and the utility trenching are fixed costs that don’t change much with an extra 200 square feet. What changes is the cabinet run, the window package, and the MEP rough-in. We price all of it before work starts, in writing, under Haven Standard Clause 1.
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 Colleyville
We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, and Mighty Buildings for Colleyville projects, and we stock the local trim, fastener, and flashing details that HOA reviews in this city actually check. When a Colleyville ARB asks for a specific brick coursing or fascia profile, we already have the sample in hand. The prefab shell arrives, our crews set it on the engineered slab, and the millwork, cabinetry, and specialty finishes are installed to the permit set. One contract, one price, one warranty.
Common New Detached ADU Problems We See in Colleyville Homes
- HOA covenant rejection after city approval. The homeowner gets a city permit number, then the ARB rejects the elevation because the 1994 CC&Rs for that subdivision explicitly ban ‘secondary dwelling units’ or ‘servant’s quarters.’ The fix is a formal membership vote to amend the covenants, and it takes months. We run this check before the survey is ordered.
- Standard slab spec on Blackland Prairie clay. The expansive clay under Colleyville moves enough each season to crack a standard residential pour within two years. A post-tension or engineered pier-and-beam foundation adds $20,000 to $40,000 and four to six weeks of lead time. Any contractor who quotes a standard slab for a detached ADU in Colleyville hasn’t built here before.
- Off-the-shelf trim that fails HOA final inspection. The original house has custom brick, a specific roof pitch, and fascia detail. The off-the-shelf trim panel doesn’t match, the ARB flags it, and now you’re tearing out and reordering custom millwork while the permit clock runs. We front-load all millwork submittals so the HOA reviews and approves the material before it’s ordered.
- Long-lead items ordered after framing starts. Custom windows, architectural glass, and specialty cabinet hardware in a Colleyville-grade finish run 8 to 14 weeks from order. Order them at framing and you’re delivering the ADU six months late. We lock the material schedule the same week the permit set is issued, and the price is already in writing.
Pricing for New Detached ADU in Colleyville, TX
A new detached ADU in Colleyville runs $285,000 to $410,000 all-in, drawings through final inspection. A studio over an existing three-car garage sits at the low end. A custom two-bedroom with architectural glass, custom cabinetry, and a brick-and-stone exterior to match a 1990s estate house sits at the high end. The foundation line item is the one most homeowners underprice: Blackland Prairie clay requires a post-tension or pier-and-beam slab at $20,000 to $40,000 more than a standard pour, and the engineering takes four to six weeks. The HOA amendment path, when required, adds time but not cost. Every price we give is written before work starts, and it doesn’t move. Call (971) 497-2402 for your free estimate, and if you already have a written proposal from another outfit, we’ll give you a free second opinion on it.
We Also Serve Cities Near Colleyville
Our New Detached ADU team works throughout the northeast Tarrant corridor, including Colleyville and the surrounding cities of Bedford, Euless, Southlake, and Hurst. Each city has its own HOA landscape and soil profile, and we handle the covenant review and foundation engineering for all of them. If you’re in one of these cities, the process is the same: written price first, permit set second, construction third.
Serving Colleyville, TX - Our Local Coverage Area
We’re based in the Colleyville 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 - New Detached ADU in Colleyville
Yes, but the path runs through a covenant amendment vote before any city permit application can move forward. In most Colleyville subdivisions, the CC&Rs were written in the 1990s and explicitly ban secondary dwelling units or servant’s quarters, so a project that’s legal under current Texas ADU law still requires a formal membership vote to amend the covenants. That vote typically takes 2 to 4 months and needs a specific quorum and majority per the HOA’s bylaws. We compile the amendment package – project description, elevation drawings, material samples, engineering summary – and submit it on your behalf. Call (971) 497-2402 and we’ll tell you exactly what your specific covenants say and what the amendment process looks like before you spend anything else.
The Blackland Prairie clay under Colleyville expands and contracts enough each season to crack a standard residential slab, so a new detached ADU requires a post-tension slab or an engineered pier-and-beam foundation instead of a standard pour. That adds $20,000 to $40,000 to the foundation line item and four to six weeks of engineering and lead time before the slab is poured. Any quote for a standard slab on a Colleyville ADU is a schedule and budget time bomb. We include the geotech report and the foundation engineering in our written price, so there’s no change order when the soil report comes back.
Because a Colleyville HOA review compares the ADU’s trim, fascia, millwork, and cabinet detailing against the original house, and the original house was custom-built with materials that aren’t stocked off the shelf. Custom millwork and cabinetry for a Colleyville ADU runs 8 to 14 weeks from order, longer if the species or finish is unusual. We front-load all millwork and cabinetry submittals the week the permit set is issued, get the HOA’s written approval, and then order. The price is fixed in writing before the order is placed, under Haven Standard Clause 1. That’s how the schedule holds.
Almost certainly not. An HOA approval for accessory storage is not an approval for an accessory dwelling unit, and most Colleyville CC&Rs treat the two as different land uses. You’ll need a new architectural review, and if the 1990s covenants still ban secondary dwelling units, you’ll need the amendment vote first. The good news is that the structure is already there, which shortens construction, but the HOA path does not shorten. We run the covenant check, prepare the new ARB submittal with matching brick and fascia details, and manage the amendment if required. Call (971) 497-2402 and we’ll look at your specific HOA documents together.
We order them before we need them, and we only order after the price is written. Custom windows, architectural glass, specialty cabinet hardware, and James Hardie Artisan lap siding all run 8 to 14 weeks from order to delivery. The moment the permit set is approved, we lock the full material schedule and the written price, then place every long-lead order in week one. On a Montclair Parc project with custom cabinetry and architectural glass, we front-loaded all submittals before the slab was poured, and the project delivered without a single long-lead surprise. That’s not luck; that’s the sequence.
Contact Ellery ADU Studio for Your Colleyville New Detached ADU
If you’re weighing a new detached ADU in Colleyville, start with a written price, not a callback promise. Ellery ADU Studio has designed, permitted, and built 900+ ADUs since 2015, every one with a written price before work started and a documented photo record when work was complete. We serve Colleyville from our Dallas-Fort Worth office, and a live person answers calls 24/7. Call (971) 497-2402 to schedule your free estimate, and if you already have a written proposal in hand, ask about our free second opinion.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Colleyville and the Dallas-Fort Worth metro since 2015.
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