Fast, Reliable Home Additions & ADU Across Westchester
Home additions and ADU construction in Westchester, FL typically run $45,000-$130,000 for room additions and $90,000-$220,000 for detached ADUs, with most projects requiring 3-6 months from permit to final inspection. Our Home Additions & ADU team knows Westchester’s single-story CBS ranch homes inside and out - we work with the county’s HVHZ requirements daily, not as an afterthought. Call (844) 665-0162 for a free estimate, and we’ll walk your property within 24-48 hours.
Why Groundwork Construction Co. of South Florida Is Westchester’s Preferred Home Additions & ADU Company
We’ve built our reputation in Westchester by treating every addition as a structural and regulatory puzzle, not just extra square footage. The 33144 zip and surrounding streets near Bird Road and Coral Way keep us busy with 1950s-1970s CBS homes that need real engineering before they can expand.
Our crew doesn’t subcontract out the hard parts. One contractor, every phase - from the first site survey through the final Miami-Dade wind-load inspection. That matters in Westchester, where a failed inspection can cost you three weeks during hurricane season.
Raymond Estevez has directed our ADU and addition work since Groundwork’s early days, and he personally reviews every HVHZ compliance plan before it hits the county permitting office. We’ve learned that Westchester homeowners don’t want surprises. They want a builder who knows the difference between a Coral Gables permit path and a Miami-Dade unincorporated one.
Our response time to Westchester averages same-day or next-day for initial consultations. We’re based in Fort Lauderdale, but we cross the county line regularly for projects from Flagami to Fountainebleau.
Our Home Additions & ADU Services in Westchester
ADU Design & Permitting
Every ADU in Westchester starts with Miami-Dade County’s zoning desk, not a sketchpad. We handle the full permitting package - site plans, flood-zone elevation certificates, utility tie-ins, and the HVHZ product approvals that unincorporated Westchester demands. Our team has worked with county inspectors on enough ADU projects to know which drawings pass on the first review and which ones get kicked back. You choose the brand, we handle the build - and the bureaucracy.
Garage Conversion ADU
Garage conversions in Westchester face a specific hurdle: most original garages weren’t built to the same flood elevation as the main structure, and the slab may need raising or the conversion needs engineered flood vents. We assess the existing foundation, check the roof structure for NOA compliance, and determine whether the garage door opening can be infilled with impact-rated wall systems. Many Westchester garages also share electrical panels with the main house that predate current code - we flag that early, before permits.
New Detached ADU
Detached ADUs in Westchester must meet setback requirements from the main structure, navigate Miami-Dade’s strict percolation and drainage rules on shallow limestone, and use NOA-approved windows and doors throughout. We partner with prefab innovators including Abodu, Dvele, Mighty Buildings, and Boxabl for homeowners who want faster timelines, but we also stick-build when the site or design calls for it. Built to spec, not to convenience.
Junior ADU & Interior Conversion
Junior ADUs work well in Westchester’s larger ranch footprints - converting part of the existing home into a separate unit with its own entrance and kitchenette. These projects still trigger HVHZ rules for any new exterior openings, and we often find original jalousie windows that must be replaced with impact-rated units. The interior separation also means fire-rated assemblies between units, which our team details from the start.
Room Additions
Single-story room additions on Westchester’s CBS homes require matching the existing concrete block construction, tying new footings to the old slab with epoxy dowels, and ensuring the roofline integrates with whatever’s up there - often multiple layers of modified bitumen over aging wood nailers. We tear off to the deck when code demands it. No shortcuts around the NOA process.
Second Story Additions
Adding a second story to a 1950s or 1960s CBS ranch in Westchester is the most technically demanding project we handle. The original slab and footings weren’t designed for the load, the roof must come off completely, and every new window and door needs HVHZ approval. We recently completed a second-story addition on a 1960s CBS ranch on a street near Bird Road. The original jalousie windows in the existing lower floor had to be replaced with impact-rated units carrying a Miami-Dade NOA, and we reinforced the new stairwell opening with steel headers. Our crew ensured the added floor tied into the existing slab with epoxy dowels to meet flood-zone requirements, and we worked with the county permitting office to pass the wind-load inspection before the hurricane season.
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 Westchester
Groundwork works with 50+ recognized industry brands across every project category, and our ADU and addition clients in Westchester get the same material choices as our kitchen and bathroom remodel customers. For cabinetry, we specify KraftMaid and Wellborn depending on your budget and style. Countertops draw from Cambria, Silestone, and Caesarstone - three of the most recognized engineered quartz brands in residential construction. Exterior cladding on additions frequently uses James Hardie siding for its HVHZ compliance and durability in South Florida’s wet season. You choose the brand, we handle the build. We don’t lock you into proprietary products or single-vendor relationships.
Common Home Additions & ADU Problems We See in Westchester Homes
- Non-NOA windows and doors that fail inspection. We’ve seen contractors install beautiful European windows that couldn’t pass Miami-Dade’s HVHZ testing. In Westchester, that’s a full tear-out and replacement - no appeals, no grandfathering. We verify every product’s Notice of Acceptance before it ships.
- Underestimating Miami-Dade permitting timelines. The county’s unincorporated permitting office moves methodically, and HVHZ product approvals add review cycles. We build realistic schedules and pre-submit product data sheets to avoid the delays that plague less experienced builders.
- Stacked roofing layers hiding structural decay. Those flat-roof CBS homes along Westchester’s interior streets have often been re-roofed two or three times since original construction, stacking layers of modified bitumen over aging wood nailers. Current HVHZ code mandates tear-off to the deck before any new system can receive a Miami-Dade NOA-compliant approval, turning what looks like a simple re-roof into a full deck inspection and potential structural repair job.
- Ignoring flood-zone requirements on ground-disturbing work. Westchester’s near-zero lot elevation and shallow Miami limestone mean any new footing, slab extension, or drainage modification needs careful attention to Miami-Dade’s flood-zone and percolation requirements. We’ve corrected too many projects where this was treated as an afterthought.
Pricing for Home Additions & ADU in Westchester, FL
Here’s what homeowners in Westchester can expect for major addition and ADU work. These ranges reflect Miami-Dade’s HVHZ compliance costs, county permitting fees, and the structural complexity typical of 1950s-1970s CBS homes.
| Project Type | Price Range in Westchester |
|---|---|
| Home Addition | $45,000-$130,000 |
| ADU Construction | $90,000-$220,000 |
| Impact Window Installation (as part of addition) | $8,000-$25,000 |
What moves you within these ranges? Foundation conditions, whether we need to raise or reinforce the existing slab, the extent of roof tear-off required, and your material selections from our 50+ brand roster. A garage conversion on good soil with minimal electrical work sits at the lower end. A detached ADU with full kitchen, impact-rated openings, and new utility connections pushes toward the upper range. We provide itemized estimates before any work begins - call (844) 665-0162 to schedule your free consultation.
We Also Serve Cities Near Westchester
Our crews regularly work in Westchester and the surrounding unincorporated and incorporated areas - Flagami to the northeast, West Miami and Coral Terrace to the southwest, and Fountainebleau to the west. Each has its own permitting path and building stock character, and we adjust our approach accordingly. From driveway to roofline, one contractor handles every phase.
Serving Westchester, FL - Our Local Coverage Area
We’re based in the Westchester 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 Westchester
Yes. In Westchester, an ADU or addition must comply with Miami-Dade County’s High Velocity Hurricane Zone (HVHZ) rules, requiring every window and door to carry a Miami-Dade Notice of Acceptance (NOA); even a simple door swap on a CBS ranch home can trigger a permit and inspection, unlike in neighboring cities like Coral Gables. We handle the NOA verification and permit submission as part of our standard process. Call (844) 665-0162 if you’re unsure whether your planned opening changes require county approval.
The original slab and footings typically lack the load capacity for a second floor, the roof must be completely removed rather than built over, and every new opening needs impact-rated, NOA-approved products. We engineer structural reinforcement, coordinate the full roof tear-off, and sequence the work to keep your home weather-protected during construction. Our field team has completed multiple second-story additions on Bird Road-area ranches - we know the pattern.
Westchester’s near-zero elevation and shallow Miami limestone substrate require flood-compliant foundations, proper drainage design, and often engineered percolation testing before the county will approve new construction. We address flood-zone requirements in our initial site survey and build them into the foundation plan from day one. Ignoring this until permitting is a common and expensive mistake.
No. Any new or converted living space in Westchester must meet HVHZ standards, which means impact-rated windows with Miami-Dade NOA approval. Original garage windows - often jalousie or single-pane - cannot remain in a legal ADU conversion. We specify replacement windows from our roster that meet code and match your aesthetic preferences, including options from Andersen, Pella, and PGT.
Westchester’s unincorporated Miami-Dade location within the HVHZ mandates tear-off to the deck, NOA-approved roofing systems, and wind-load inspections that incorporated cities with older codes may not require. Those flat-roof CBS homes along Westchester’s interior streets have often been re-roofed two or three times since original construction, stacking layers of modified bitumen over aging wood nailers - and current HVHZ code now mandates tear-off to the deck before any new system can receive a Miami-Dade NOA-compliant approval, turning what looks like a simple re-roof into a full deck inspection and potential structural repair job. We price this honestly upfront rather than discovering it mid-project.
Ready to expand your Westchester home? Call Groundwork Construction Co. of South Florida at (844) 665-0162 for a free, on-site estimate. We’ll review your property, explain the HVHZ requirements that apply to your specific project, and give you a clear timeline from permit to completion. One contractor, every phase - from driveway to roofline, built to spec, not to convenience.
Written by Raymond Estevez, Owner at Groundwork Construction Co. of South Florida, serving Westchester and South Florida homeowners since our founding.