Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Fast, Reliable Home Additions & ADU Across Olympia Heights
Adding square footage in Olympia Heights means building to Miami-Dade County’s High Velocity Hurricane Zone standard, not just the Florida Building Code. That distinction catches a lot of people off guard, and it’s exactly why the scoping happens before the quote. For a permitted addition or ADU on a 1950s concrete block ranch near Bird Road, the real questions are about NOA compliance, limestone excavation, and county setbacks. Our Home Additions & ADU team handles those questions every week. Call Tom Barrett at (877) 610-1318 and we’ll walk the lot with you before a single number goes on paper.
Why Barrett & Sons Construction Is Olympia Heights’s Preferred Home Additions & ADU Company
We’re the owner-operated option. Tom Barrett founded Barrett & Sons in 1998, and his sons run the crews that work in Olympia Heights today. When you call, a live person answers, 24 hours a day. When work starts, the name on the truck is the name on the contract. That matters to homeowners in 33165 who’ve been burned by a national outfit that quoted one price on the phone and delivered a different bill at the door.
Our reputation here was built on permits, not promises. Every eligible job in Olympia Heights gets permits pulled and inspections signed by Miami-Dade County. Every price change arrives as a written change order before work proceeds. And every job carries the 90-Day Done Right Promise, written on the contract: if it’s not done right, Tom comes back and makes it right, one call.
We know the streets. We’ve worked additions near Olympia Heights Park, garage conversions off SW 107th Avenue, and detached ADUs on the wide lots west of the Palmetto Expressway. We know the inspectors, we know the caprock, and we know which impact window specs the county will actually accept.
Our Home Additions & ADU Services in Olympia Heights
New Detached ADU
A standalone ADU in Olympia Heights typically runs $90,000 to $220,000. That range moves based on square footage, whether you’re on county sewer or septic, and how deep the limestone sits on your lot. We verify Miami-Dade NOA compliance on every structural component, from the roof underlayment to the fasteners, before we quote. Spec one non-approved product and the inspector will flag it on-site.

ADU Site Prep & Utilities
This is where Olympia Heights surprises people. Dig 18 inches and you might hit oolitic limestone caprock that a standard trencher can’t touch. We’ve swapped in rock saws on flat lots near SW 40th Street and added two days to rough-in because of it. Trenching for water, sewer, and electric happens before framing, and we scope it with the county’s well and septic setback rules in mind, not after.

Garage Conversion ADU
Converting an existing garage in Olympia Heights runs $30,000 to $80,000, and the first question is whether the slab and existing block walls can carry the new use. Many of these 1950s-era garages were never strapped for hurricane uplift, and the electrical panel often can’t hold the load an ADU adds. We open the walls, document what’s there, and price the retrofit honestly.

Junior ADU & Interior Conversion
When the space is already inside your home, a Junior ADU can work well on Olympia Heights lots where a full detached build won’t clear county setbacks. This is often the fastest path for aging parents or a returning adult child. Separate entrance, kitchenette, and its own bath: three things that trigger additional code requirements we handle from day one.

What happens when you call
- 1
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 Olympia Heights
We install materials you can look up: Techo-Bloc for patio and walkway pavers, Cambridge Pavers for driveway work, and Quikrete products for footings and slab work where site conditions call for them. We don’t spec mystery brands off a van. On a detached ADU in Olympia Heights, we’re often pairing those hardscape materials with the structural and opening packages the county requires, all sourced from local yards so we’re not waiting on a truck from two states away when the inspection’s scheduled.
Common Home Additions & ADU Problems We See in Olympia Heights Homes
- HVHZ specs that fail inspection. A window or underlayment that passes Florida Building Code statewide but lacks a Miami-Dade NOA will be rejected here. We’ve seen jobs stall for weeks while a substitute gets sourced. We verify every spec before pulling the county permit.
- Limestone shallower than expected. The oolitic caprock under Olympia Heights can sit 12 to 30 inches below grade. A footing plan drawn on soil assumptions from Broward won’t survive contact with a trencher here. We scope excavation with rock sawing in the budget from the start.
- Septic and well setbacks ignored. Unincorporated Miami-Dade means county rules govern. A detached ADU near an existing drainfield or well needs a survey before design starts. Skip that step and the county will send you back to the drawing board.
- Old panels and flat roofs. The concrete block ranches of 33165 predate the post-Hurricane Andrew code overhaul. Electrical panels often can’t carry an ADU’s load, and flat built-up roofs need full tear-off and HVHZ-compliant replacement before you can tie a new structure in.
Pricing for Home Additions & ADU in Olympia Heights, FL
Here’s what we’re seeing in Olympia Heights right now. A full home addition runs $45,000 to $130,000. A detached ADU starts at $90,000 and can reach $220,000 depending on size and site work. A garage conversion falls between $30,000 and $80,000. These numbers are specific to the 33165 market, where NOA compliance and limestone excavation add real cost that generic online calculators never mention.
| Project Type | Typical Range in Olympia Heights |
|---|---|
| Home Addition | $45,000 - $130,000 |
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion | $30,000 - $80,000 |
What moves the number? Depth to caprock, distance to county sewer, whether the main panel needs an upgrade, and whether your existing roof can be tied in or needs a full replacement. We write all of it down: scope in writing, allowances in writing, change orders in writing. Call (877) 610-1318 for a free estimate with no trip charge inside the county.
We Also Serve Cities Near Olympia Heights
Our crews handle projects across southwest Miami-Dade. If you’re in Westwood Lake, Sweetwater, University Park, or Sunset, the same NOA verification and limestone-scoping process applies. We schedule locally and coordinate from our South FL office, so the crew that quotes your job is the crew that builds it. Ask about Home Additions & ADU work in your neighborhood.
Serving Olympia Heights, FL - Our Local Coverage Area
We’re based in the Olympia Heights 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 Olympia Heights
Yes. Every impact window and exterior door on a new ADU in Olympia Heights must carry a Miami-Dade Notice of Acceptance, not just a Florida Building Code approval. We verify NOA numbers before we write the quote, because a non-compliant spec will fail county inspection and stall your job. Call (877) 610-1318 and we’ll show you the NOA paperwork before you sign anything.
The limestone caprock adds equipment cost and time. Where a standard trencher handles soil in most of Florida, Olympia Heights lots often require a rock saw or hammer attachment once you hit the caprock, sometimes at 18 inches or less. Site prep can jump by several thousand dollars depending on depth. We scope it with test digging before we quote, not as a surprise change order.
Sometimes, but not always. The garage’s existing block walls and slab get evaluated for hurricane strapping and load capacity, and the main electrical panel often can’t handle the additional load without an upgrade. We’ll tell you exactly what’s needed after we open the walls and check the panel. Estimates are free: (877) 610-1318.
Unincorporated Miami-Dade enforces county setbacks for septic drainfields and wells, which means your ADU’s footprint depends on where those systems already sit on the property. We survey those locations before designing anything. A redesign forced by a missed setback is expensive and avoidable, and we don’t let it happen.
Yes, the driveway and any new curb cut require their own county permit in Olympia Heights, typically included in our site prep scope. We’ll flag it early so you’re not caught with a completed ADU and no legal access. Call (877) 610-1318 and we’ll walk the site with you from the street to the back lot line.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Olympia Heights and the surrounding communities of southwest Miami-Dade.







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