Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
After
Before
After
Before
AfterFast, Reliable Home Additions & ADU Across Westchester
A room addition or ADU in Westchester typically runs $45,000 to $130,000 for the project as a whole, and the single biggest variable is not square footage. It’s whether your contractor actually knows Miami-Dade County’s High Velocity Hurricane Zone code. We do. Barrett & Sons Construction has been building in Westchester long enough to know that every permit here gets scrutinized harder than almost anywhere else in Florida, and we plan for that from the first site visit. If you’re thinking about adding a bedroom, a second story, or a detached ADU in the 33144 zip code, call Tom and his sons at (877) 610-1318. We’ll walk your lot, look at your slab, and tell you what this will actually take. Estimates are free.
Why Barrett & Sons Construction Is Westchester’s Preferred Home Additions & ADU Company
Westchester homeowners tend to be skeptical of contractors, and honestly, most of them earned that skepticism. The neighborhood’s housing stock is old enough that every addition surfaces problems a cheap bid never mentions: missing roof straps, slab edges that need saw-cutting, water tables that show up three feet down in July. Our Home Additions & ADU team has handled enough of these jobs near SW 8th Street, Coral Way, and Bird Road that we quote the real scope up front, not the scope that gets your signature.
Tom Barrett founded this company in 1998 and still answers his own phone. His sons run the crews. When we say we serve Westchester, we mean our trucks are there during the week, our crew members live in South Florida, and our name, address, and license number are published where anyone can look them up. We carry a 90-Day Done Right Promise on every contract: if something isn’t right, one call brings Tom back. No national outfit can say that, because their branch manager moved to another region last quarter.
We also write every scope, every allowance, and every price change as a written change order before work proceeds. In Westchester, where a failed HVHZ inspection can add thousands to the real cost of a job, that paper trail matters. The permit inspector works for you, not for us. We like him there.
Our Home Additions & ADU Services in Westchester
ADU Design & Permitting
Westchester sits entirely inside the HVHZ, which means every ADU here must use Miami-Dade Notice of Acceptance (NOA)-approved products. That is not a suggestion and not an upgrade. It’s the law, and it’s enforced. We handle the full design and permitting sequence: site survey, architectural drawings, HVHZ product submittals, Miami-Dade permit package, inspections through final sign-off. A detached ADU in Westchester typically runs $90,000 to $220,000, with much of that cost tied to the foundation retrofit and NOA-rated structural hardware the code demands.
Garage Conversion ADU
Converting a Westchester garage into a living unit usually runs $30,000 to $80,000. The catch: most of these garages in the neighborhood date to the 1950s and 1960s, meaning the existing slab and walls predate Hurricane Andrew’s 1992 code reforms. That means anchors, embedments, and connectors often get flagged during inspection. We budget for HVHZ-rated stainless hardware from day one, not after a failed inspection emails you a correction notice. Salt-laden air here corrodes standard galvanized connectors within a few years, and Miami-Dade inspectors know exactly where to look.
New Detached ADU
A new detached ADU on a Westchester lot means excavation, and excavation here means water. The water table sits 2 to 4 feet below grade across much of the neighborhood, and during the June-to-October wet season any footing trench becomes a pond without a dewatering plan. We include that plan in the written scope. A detached ADU gives you the most design freedom, but it also carries the heaviest site work. Plan on $90,000 to $220,000 for a code-compliant build, including the thickened-edge slab and anchor-bolt retrofit Miami-Dade will require.
Junior ADU & Interior Conversion
A junior ADU, usually a converted interior space within an existing home, is the most affordable path to rental income or a place for aging parents. These often run on the lower end of our home addition pricing, and because they stay within the existing footprint, they trigger fewer structural upgrades. But if your conversion touches exterior walls or adds a bathroom, the HVHZ requirements follow you there, too. We’ll tell you exactly which triggers apply on your specific property before you spend a dollar on plans.
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.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Westchester
We install materials you can look up, not mystery brands off a van. For hardscapes around new ADUs and room additions, we regularly use Techo-Bloc and Cambridge Pavers, which carry Miami-Dade NOA approvals for the wind and water conditions we build in here. For concrete work and footings, we spec Quikrete products rated for South Florida’s high-moisture, salt-exposed environment. Because we build in Westchester every week, we keep these brands and the associated NOA paperwork moving through our supply chain quickly. That means fewer delays waiting on product submittals while your permit sits on a plan reviewer’s desk.
Common Home Additions & ADU Problems We See in Westchester Homes
- Missing roof-to-wall strapping on pre-1992 CBS homes. Most Westchester ranch homes were built before Hurricane Andrew changed the code. When you add square footage, the inspector will check the existing structure’s uplift path, and if the straps aren’t there, the retrofit becomes part of your job. A contractor who doesn’t know this will hand you a change order mid-project.
- Slab edges with no stem wall. Many 1960s Westchester slabs are thickened-edge pours with no vertical stem wall. When Miami-Dade requires new anchor bolts or strap retrofit, the slab edge has to be saw-cut and epoxy-anchored. Out-of-county contractors miss this until the first failed inspection.
- Water table surprises during ADU excavation. Dig down three feet in Westchester during summer and you hit water. Without a dewatering plan written into the original scope, your project stops for weeks and the schedule blows out. We write the dewatering plan into the bid.
- Corrosion from salt air and humidity. Westchester gets 60-plus inches of rain annually, and the air off Biscayne Bay carries salt. Standard galvanized connectors rust fast. HVHZ-rated stainless or hot-dipped galvanized hardware is not a premium upgrade here; it’s the difference between a job that passes inspection and a job that fails it two years later.
Pricing for Home Additions & ADU in Westchester, FL
| Project Type | Westchester Price Range |
|---|---|
| Room Addition | $45,000 - $130,000 |
| Second Story Addition | $90,000 - $220,000 |
| Garage Conversion ADU | $30,000 - $80,000 |
A cheap bid that leaves out the strapping retrofit, the dewatering plan, or the NOA-rated hardware isn’t cheaper. It’s a surprise waiting for a date. Every Barrett & Sons quote includes those items as line items, in writing, before you sign anything. Call (877) 610-1318 for a free, written estimate.
We Also Serve Cities Near Westchester
We work throughout the area, including Flagami, West Miami, Coral Terrace, and Fountainebleau. If you’re a few blocks outside the 33144 boundary, don’t let that stop you. We serve Home Additions & ADU in Westchester and the surrounding communities with the same written-scope, permit-pulled approach.
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
Does every Westchester home addition trigger Miami-Dade’s ‘50% rule’?
No, not every addition triggers the 50% rule, but any substantial renovation or addition on a pre-1992 home in Westchester can. The rule requires that if the cost of improvements exceeds 50% of the structure’s assessed value, the entire building must be brought up to current HVHZ code, not just the new square footage. We evaluate your specific project against the rule during the estimate, and we tell you in writing whether it applies. That conversation costs you nothing. Call (877) 610-1318.
Why do Westchester ADU permits take longer than in other Miami-Dade neighborhoods?
Westchester permits go through the same Miami-Dade building department as the rest of the county, but the neighborhood’s older CBS housing stock triggers more structural review back-and-forth. Plan reviewers know these 1950s and 1960s homes often lack proper roof-to-wall strapping and stem-wall foundations, so they ask for more documentation up front. We package NOA product submittals and structural calculations together from the start, which shortens the review time significantly.
What NOA-approved products are actually required for a Westchester room addition?
Miami-Dade Notice of Acceptance products are required for any structural component exposed to wind uplift or water intrusion: roof coverings, roof-to-wall connectors, anchor bolts, embedments, fasteners, and exterior window and door systems. In practice, for a Westchester room addition, that means HVHZ-rated stainless or hot-dipped galvanized straps, clips, and anchors, plus impact-rated windows and doors. A generic Florida Building Code approval is not enough inside Westchester. We source and document all of it.
How does HVHZ documentation affect my homeowners insurance after a Westchester addition?
If your addition is permitted, inspected, and signed off with HVHZ documentation, you can present that paperwork to your insurer. It demonstrates the new square footage was built to the strictest wind-load standard in the continental United States, which in many cases helps with coverage terms and premiums rather than hurting them. An unpermitted addition is a different story entirely, and it can jeopardize a claim. We pull permits on every eligible job, and we hand you the signed inspection record at the end.
Can I convert my Westchester garage into an ADU without raising the roof?
Yes, in most cases you can convert a Westchester garage into an ADU without touching the roofline, provided the existing structure passes HVHZ inspection or you retrofit it to pass. The more common constraint is the slab and the walls, not the roof. Flat or low-pitched roofs on these 1950s and 1960s garages often need strapping retrofits, and the slab edge needs anchor work. We’ll tell you what your specific garage actually needs. Call (877) 610-1318 for a free estimate.
Contact Barrett & Sons Construction for Home Additions & ADU in Westchester
If you live in Westchester and you’re planning a room addition, a second story, or an ADU, start with a phone call. Tom Barrett and his sons will walk your property, look at your slab and your roof, and tell you what the HVHZ code will require on your specific home. You’ll get a written line-item estimate, a permit plan that actually passes review, and a 90-Day Done Right Promise on the back end. Call (877) 610-1318 to schedule your free estimate.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Westchester and South Florida since 1998.