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-$130,000, and the project will live or die on one thing: whether it meets Miami-Dade High Velocity Hurricane Zone code. Barrett & Sons Construction has been building and remodeling in South Florida since 1998, and we pull permits and pass inspections on every eligible job in the 33144 ZIP code. If you’re planning an addition off Coral Way or a garage conversion near Bird Road, call (877) 610-1318 and we’ll give you an honest, line-item estimate before you sign anything.
We’re the owner-operated shop where Tom Barrett’s sons run the crews, and we live close enough to Westchester that if something isn’t right, Tom wants to know about it the same week, not next quarter. Every price change arrives in writing before a single nail moves. That’s how we’ve done it for 29 years.
Why Barrett & Sons Construction Is Westchester’s Preferred Home Additions & ADU Company
Westchester isn’t a neighborhood where you can hand a job to an out-of-town crew and hope for the best. The housing stock is specific: single-story CBS ranch homes built between 1950 and 1975, concrete block on thickened-edge slabs, with flat or low-pitched roofs that predate Hurricane Andrew’s 1992 code overhaul. A contractor who doesn’t know what those foundations look like is going to be surprised mid-project. We aren’t.
Our Home Additions & ADU team has worked on room additions, detached ADUs, and garage conversions throughout Westchester, and we know what Miami-Dade inspectors flag on these houses before we ever open a wall. Dispatch and scheduling are coordinated from our Miami office, and crews serve Westchester locally, so you’re not waiting on a crew driving down from Broward. A live person answers our phone 24/7. Not a voicemail box. Not a call center.
Every contract carries the 90-Day Done Right Promise in writing: if the work isn’t done right, one call brings Tom back. And because Tom publishes his name, address, and license number, you can verify who you’re hiring before you sign. We’d expect you to.
Our Home Additions & ADU Services in Westchester
ADU Design & Permitting
Building an ADU in Westchester means designing to Miami-Dade HVHZ standards from day one. We handle the drawings, the NOA product selections, the permit application, and the inspection calendar. Most Westchester ADUs we design go in as detached units behind existing CBS homes, and we size the slab, the hold-downs, and the roof-to-wall connections to pass wind-load review the first time. That planning keeps you out of the permit-review limbo that stalls half the ADU jobs in this ZIP code.
Garage Conversion ADU
A garage conversion in Westchester usually starts at $30,000, and the first question is whether your existing garage slab and walls can carry the new loads. Most 1950s and 1960s garages here were built as car storage, never as living space, so you’ll likely need floor leveling, stem-wall or thickened-edge reinforcement, and impact-rated window or door openings. We’ll tell you what’s required before we start, and any change to that scope comes as a written change order, never a surprise invoice.
New Detached ADU
A new detached ADU in Westchester runs $90,000-$220,000 with full NOA compliance. That price includes everything a cheap bid leaves out: dewatering the site during excavation, saw-cut and epoxy-anchored hold-downs on the slab edge, NOA-listed stainless connectors throughout, and impact-rated openings. In this neighborhood, the water table sits two to four feet below grade, so any footing or underground work needs a dewatering plan. We include it in the quote. Out-of-county contractors often don’t, and then you meet it as a change order.
Junior ADU & Interior Conversion
A junior ADU or interior conversion is the most cost-effective way to add a rental unit or in-law suite inside your existing Westchester home. These projects can trigger Miami-Dade’s 50% rule depending on the scope, which means your whole house may need to come up to current HVHZ code, not just the converted space. We walk you through that determination before you spend a dollar on drawings. If a contractor tells you permits are optional on an interior conversion in Westchester, ask them to put that in writing. They won’t.
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
For paver work tied to your addition, driveway, or ADU site prep, we install Techo-Bloc and Cambridge Pavers products, two brands engineered to hold up in South Florida’s wet, salty air. We keep common materials available locally for Westchester customers, so you’re not waiting on a specialty order when the project is ready to move. If a product doesn’t carry Miami-Dade Notice of Acceptance for our wind zone, it doesn’t go on a Westchester job. That’s not a preference; it’s the code.
Common Home Additions & ADU Problems We See in Westchester Homes
- Missing roof-to-wall strapping. Homes built before Hurricane Andrew often have no hurricane straps at the truss-to-wall connection. Miami-Dade inspectors flag it immediately, and it has to be retrofitted before any addition can be framed and tied in.
- Corroded fasteners and connectors. Salt-laden air, 60-plus inches of annual rain, and constant humidity eat standard galvanized hardware. Westchester additions need NOA-listed stainless or heavy galvanized connectors, and we spec them on every job.
- Thickened-edge slabs with no stem wall. Most 1960s Westchester foundations are an 8-inch block wall sitting on a simple thickened-edge slab. When an addition triggers an anchor-bolt or strap retrofit, the slab edge often has to be saw-cut and epoxy-anchored. That’s a hidden cost out-of-county contractors leave off the draw schedule.
- Dewatering surprises during excavation. The water table under Westchester sits two to four feet below grade. Any footing or underground work in the wet season will need constant dewatering, and that cost should be in the quote, not discovered mid-dig.
Pricing for Home Additions & ADU in Westchester, FL
What does an addition or ADU actually cost in Westchester? Here are honest ranges for the work we do most often, calibrated to this local market and Miami-Dade’s code requirements.
| Project | Typical Westchester Range |
|---|---|
| Room Addition (HVHZ-compliant) | $45,000-$130,000 |
| ADU Construction (full NOA compliance) | $90,000-$220,000 |
| Garage Conversion ADU | $30,000-$80,000 |
| Impact Window Installation | $8,000-$25,000 |
Your final number depends on the size of the addition, the condition of the existing structure, and how much the 50% rule pulls into scope. We give free estimates with written, line-item pricing, and every allowance is spelled out in the contract. If an allowance isn’t on paper, it’s a surprise waiting for a date. Call (877) 610-1318 and we’ll walk the property with you and put real numbers on the table.
We Also Serve Cities Near Westchester
While this page focuses on Home Additions & ADU in Westchester, our crews also work regularly in Flagami, West Miami, Coral Terrace, and Fountainebleau. If you’re a few blocks outside the 33144 ZIP line, call anyway. Chances are we’re already working down the street.
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, it often does. The 50% rule kicks in when the cost of your proposed work exceeds 50% of the assessed value of the existing structure, and in that case the entire house must be brought up to current HVHZ code, not just the new addition. That usually means a full roof-to-wall strap retrofit, impact-rated openings, and structural upgrades to the existing CBS shell. On room additions behind older Westchester ranches, we see this trigger all the time, and we determine it at permit review before you’re financially committed. Call (877) 610-1318 and we’ll review your property specifics with you.
HVHZ approval means a building product carries a Miami-Dade Notice of Acceptance, meaning it has passed wind-load and impact testing for the High Velocity Hurricane Zone. Westchester sits entirely inside that zone, which has the strictest wind-load construction requirements in the continental U.S. Broward County is outside it, so the same window, fastener, or roof assembly can be legal up there and illegal here. On a Westchester addition or ADU, every structural connector, window, door, and roof component has to be NOA-listed. We only spec products that are.
You’ll likely need slab-edge saw-cutting and epoxy-anchored hold-downs to satisfy Miami-Dade’s strap and bolt requirements, because older CBS homes were built on thickened-edge slabs with no stem wall to anchor into. We budget for that work in the original quote. On a room addition behind a 1962 CBS ranch off SW 8th Street, our crew found the existing roof had no hurricane straps at the truss-to-wall connection. We saw-cut the slab edge, epoxy-anchored new hold-downs, and installed NOA-rated stainless connectors before framing the addition, so the final inspection cleared with zero corrections and the homeowner could document full HVHZ compliance for their insurer. That work should be in your quote from day one, not handed to you mid-project.
Yes. A junior ADU or interior conversion that adds sleeping quarters, plumbing, a kitchenette, or new electrical circuits requires permits and inspections in Westchester, no matter what a contractor tells you. Skipping permits on this kind of work in Miami-Dade also creates a problem when you sell or file an insurance claim. We pull permits and sign inspections on every eligible job, because the permit inspector works for you, not for us. That’s the whole point.
It can, and the key word is documented. Insurers want proof that the work was permitted, inspected, and built with NOA-approved products, especially in a wind zone as strict as Westchester’s. We provide that documentation on every addition and ADU we complete, including the final inspection sign-off and product approvals. You can take it to your carrier and ask for a premium review. Call (877) 610-1318 and we’ll talk through what a compliant project includes and what it’ll leave you holding at the end.
Call Barrett & Sons Construction for Your Westchester Addition or ADU
Planning an addition or ADU in Westchester isn’t just a weekend decision. You’re dealing with HVHZ code, the 50% rule, old CBS construction, and a water table that shows up the moment you start digging. You need a contractor who’s done it here, with a written price, permits pulled, and a name you can look up. Tom Barrett publishes his name, address, and license number. His sons run the crews. The 90-Day Done Right Promise is on every contract. Call (877) 610-1318 today to schedule your free estimate, and ask for a written line-item quote. You’ll know exactly what you’re getting, and exactly what it costs, before you sign anything.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Westchester and surrounding South Florida communities since 1998.