Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Fast, Reliable Home Additions & ADU Across Cooper City
Home additions and ADU construction in Cooper City run anywhere from $45,000 for a straightforward room addition up to $220,000 for a fully permitted detached ADU with kitchen and bath. Cooper City is not like building in Davie or Pembroke Pines. The water table sits 12 to 18 inches below grade across much of the city, the subsoil is organic muck and peat left from drained Everglades wetland, and homes built before 1994 rarely have the hurricane strapping current code demands. We’ve opened enough Cooper City walls to know what’s behind them. If you’re planning an addition or an ADU here, call Barrett & Sons Construction at (877) 610-1318. The estimate is free, and it comes with a written scope of work.
Why Barrett & Sons Construction Is Cooper City’s Preferred Home Additions & ADU Company
We’re the owner-operated crew that actually shows up in Cooper City. Tom Barrett’s sons run our job sites, and most days you’ll find one of them walking a Cooper City footing inspection or meeting the permit inspector on a second-story addition off Sheridan Street. That matters in a city where the building department knows the C-11 canal soil patterns and writes correction notices for things a national outfit’s sales rep has never seen. Tom founded the company in 1998, and his name, address, and license number are published for anyone to look up. We don’t mind that. We’re counting on it.
Our Home Additions & ADU team has worked through the specific failure modes Cooper City’s aging tract homes throw at you: slab-on-grade foundations settling unevenly, pre-Andrew roof framing with no tie-downs, and exterior walls that hide failed waterproofing behind stucco. We pull permits on every eligible job. We write every allowance and price change as a signed change order before work proceeds. That’s how Tom has run it for over 29 years, and it’s the same way his sons run it in Cooper City today.
Every completed job carries the 90-Day Done Right Promise in writing. One call brings Tom back. We also answer our phones with a live person, 24/7, not a voicemail tree. And for our Cooper City neighbors, we don’t charge a trip fee inside the county.
Our Home Additions & ADU Services in Cooper City
ADU Design & Permitting
Cooper City has its own permitting path for accessory dwelling units, and the process starts with a site survey that reads the water table before the first drawing is finalized. We handle the full design and permitting sequence, including the Broward County building department submittals and any South Florida Water Management District comments that come back on lots near the C-11 canal. You get a permit set that reflects what the inspector will actually sign off on, not a generic plan that gets bounced back three times.

Room Additions
Most Cooper City room additions are built onto 1970s to 1990s concrete block homes that were never designed for expansion. The tie-in detail is where cheap work shows up first. We dig, dewater if needed, and pour footings that account for the compressible muck under the fill. Then we tie the new roof structure into the existing framing with hurricane-rated hardware, even if the existing framing pre-dates the current code. A room addition in Cooper City typically starts around $45,000 and moves up from there based on size, foundation conditions, and finish level.

Garage Conversion ADU
Converting an attached garage into a living unit is the most cost-effective ADU option for many Cooper City homeowners, running roughly $30,000 to $80,000. The catch is that opening the garage wall on a pre-1994 home often triggers the building department to require hurricane mitigation on the opened sections, and sometimes the entire garage-to-house wall assembly. We plan for that in the allowance structure from day one, so you’re not handed a five-figure surprise at the framing inspection.

Second Story Additions
A second story on a Cooper City home is a structural commitment. The existing slab and footings were poured for a single-story load, and the muck underneath has been consolidating for 30 to 50 years. Before we ever quote a second-story addition, we evaluate the existing foundation, the block wall reinforcement, and the roof framing. Often the most honest answer is that a second story is viable only with a new footing and steel moment frame, and we’ll tell you that in writing before you spend a dollar. Second-story additions are part of that $45,000-$130,000 range, and the soil under your lot decides where you land in it.

Junior ADU & Interior Conversion
For a smaller footprint, a junior ADU or interior conversion, like a master suite expansion or a den turned into a studio with its own entrance, can stay under $45,000 if the existing footprint is workable. The Cooper City variable is again the slab. Interior conversions that don’t add foundation area avoid the dewatering and soil-consolidation risk entirely, which is why they’re often the fastest permitted path.

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.
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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 Cooper City
We carry material lines our Cooper City customers can look up and verify. Simonton and PGT impact-rated windows and doors show up on most of our addition and ADU projects because Broward wind-load compliance demands a window that’s been tested, not a mystery brand off a van. For sliders and patio assemblies, we use Ply Gem when the spec calls for it. We order direct, we know the lead times, and we don’t ask a Cooper City homeowner to trust us on a brand we can’t put a spec sheet behind.
Common Home Additions & ADU Problems We See in Cooper City Homes
- Slab settlement transferred into the new tie-in. The builder-grade slabs in 1970s-80s Cooper City tract homes were poured on fill over organic muck, and after thirty or forty years of consolidation, adding a new footing and connecting it to an old slab invites differential settlement. The new corner drops a quarter inch, and the drywall cracks at the joint. We address this with engineered fill and isolation joints where the soils demand it.
- Pre-1994 walls lacking hurricane strapping. Open the wall of a Cooper City home built before Andrew, and you’ll usually find no continuous load path from roof to foundation. Once that wall is opened on a permitted addition, the inspector can require retrofit strapping, and it was never in the original allowance. We write that risk into the contract so it’s a line item, not a shock.
- Standing water at 14 inches when cutting a new footing. We’ve set up dewatering on Cooper City jobs more times than we can count. The high water table near the Everglades buffer means saturated soil sits right under the grass, and any ground-up foundation work has to plan for pumping, over-excavation, and sometimes a revised footing design that holds until the next inspection.
- Failed waterproofing behind original stucco. Opening a wall for an addition frequently reveals that the original flashing or moisture barrier has been failing for years. In Cooper City’s humid, storm-driven climate, that trapped moisture has been working on the framing the whole time. We address it before we close the wall, and we show you photos of what we found.
Pricing for Home Additions & ADU in Cooper City, FL
These are the real market ranges for Cooper City, not a national website’s guess. A room addition runs $45,000 to $130,000. A garage conversion ADU runs $30,000 to $80,000. A new detached ADU with kitchen and bath runs $90,000 to $220,000 depending on size, site work, and how much dewatering the soil requires. What moves your number most in Cooper City is what we find when we open the wall: pre-Andrew strapping to retrofit, waterproofing to replace, or a slab sitting on muck that needs an engineered footing. We quote honestly, in writing, with allowances broken out. Call (877) 610-1318 and we’ll walk your house and give you a free estimate. If you have another contractor’s written estimate, bring it in. We’ll give you a free second opinion on it.
| Project Type | Cooper City Price Range |
|---|---|
| Home Addition | $45,000 - $130,000 |
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion | $30,000 - $80,000 |
Every Barrett & Sons contract includes the 90-Day Done Right Promise in writing. If it’s not done right, Tom comes back and makes it right, one call. We also honor a permanent 10% senior and veteran discount on every Cooper City project.
We Also Serve Cities Near Cooper City
While this page covers Home Additions & ADU in Cooper City, our crews work across the western Broward corridor. You’ll see us running permits in Pine Island Ridge, Davie, Southwest Ranches, and Pembroke Pines. The soil conditions change a bit from town to town, but the way we write change orders doesn’t.
Serving Cooper City, FL - Our Local Coverage Area
We’re based in the Cooper City 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 Cooper City
The water table sits 12 to 18 inches below grade across much of Cooper City, which means any new footing excavation will likely hit saturated soil. We plan for dewatering, over-excavation of the organic muck, and compacted structural fill before forms go up. The foundation design has to assume the water will return after backfill, so we spec accordingly. For an exact number on your lot, call (877) 610-1318. Estimates are free.
You’ll get a written change order before we touch anything. Once a pre-1994 wall is opened on a permitted project, the building inspector can require roof-to-wall straps, anchor bolts, and impact-rated openings on the affected sections. We write a retrofit allowance into every Cooper City contract so that requirement is priced, signed, and approved before the job starts, not discovered at the rough inspection.
The South Florida Water Management District’s C-11 canal network runs along Cooper City’s perimeter, and the homes built closest to those canals in the 1970s and 1980s sit on fill over soils that have consolidated unevenly for decades. The result is differential slab settlement that shows up as interior cracking and doors that no longer latch. We’ve seen the pattern enough times to recognize it before the first footing is cut, and we design tie-ins to accommodate the movement. Call (877) 610-1318 to have us look at your slab.
Generally yes, the code upgrade follows the work. The garage-to-house wall, the opened sections, and any new electrical or plumbing you run must meet current code, but the untouched portions of the house are usually grandfathered. The one recurring exception is the hurricane strapping on the opened wall assembly, which the inspector can require by reference to the current Florida Building Code. We scope that in from the first proposal.
A Cooper City detached ADU typically breaks into five draws: contract signing and permit submittal, foundation and dewatering completion, rough framing and roof dry-in, rough mechanicals and inspections, and final finishes with certificate of occupancy. Each draw is tied to a signed inspection or milestone you can see with your own eyes. Tom Barrett reviews every draw request personally before it goes to you, and any change to the draw schedule is a written change order. Call (877) 610-1318 for a complete project plan.
Planning an addition or ADU in Cooper City means planning for what’s under the slab, behind the stucco, and pre-dating the 1994 code. We’ve done it long enough to know exactly what we’ll find, and we price it honestly before the first cut. Call Barrett & Sons Construction at (877) 610-1318 to schedule your free estimate. Tom or one of his sons will walk the site with you, and the quote you get is the price you’ll see on the contract.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Cooper City, FL.







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