Home Additions in Miami — a third project type
Home additions in Miami-Dade, Broward, and Palm Beach County — not a remodel, not a new build. New foundation or load-path retrofit, new envelope tied into the existing one, MEP verified against the existing service, and a permit set that lives in the gap between alteration and new construction. Single-family homes only.
Full-scope addition: design, structural engineering, MEP integration, permits, inspections, build, and finish. Three project types.
Single-family homeowners in Miami-Dade, Broward, and Palm Beach County who want one licensed GC running the project end to end.
$300–$550 per square foot of new conditioned space. Garage conversions run lower; second-story runs higher. Site visit before quoting.
Six phases: site visit, scope + engineering, permit set, build, inspections, certificate of occupancy. Schedule depends on type.
A home addition is its own project type
Adding conditioned square footage to an existing home is structurally and procedurally different from whole-home remodeling in Miami or building a new house from dirt up. The new portion has to meet current Florida Building Code 8th Edition requirements, including HVHZ envelope on every new exterior opening in Miami-Dade and most of Broward. The existing portion stays under whichever code cycle it was built to — except where the addition forces it forward.
That last clause is the entire complexity. The new portion is a code-current new build. The existing portion is grandfathered. The seam between them— where new framing ties into the existing roof, where the new electrical home-run lands at the existing panel, where the new slab meets the existing foundation — is where the work is. Treat an addition as "kitchen remodel plus new walls" and the inspector finds the seam.
Room Additions
Single-room or multi-room horizontal additions on a new foundation, tied into the existing exterior wall. New slab or stem wall, new framing, new roof tied into the existing roof structure, new HVAC zone, new electrical home-runs to the existing panel, new plumbing if the room is wet. The existing exterior wall becomes interior — full new-construction technique on the new portion, integration technique on the seam.
Second-Story Additions
A full or partial second floor over an existing single-story home. The engineering is the inverse of a room addition: no new foundation footprint, but the existing first-floor structure has to be verified to carry the new dead and live loads, and in HVHZ jurisdictions the lateral load path has to be verified against current code. That commonly means foundation reinforcement, first-floor wall reinforcement, hurricane strapping retrofit through the existing roof, and sometimes a new shear wall. Rarely as simple as building the same square footage on top — a structural retrofit of the existing house plus a new build above it.
Garage Conversions
Turns an existing attached or detached garage into conditioned living space. The slab, framing, and roof are already there, but none of it is conditioned-space rated. The conversion is an envelope upgrade, an MEP buildout, and a permit-and-inspection sequence that re-classifies the space from accessory to primary occupancy. The exterior garage door usually gets infilled with framing and a new exterior wall assembly that has to meet HVHZ envelope requirements like any other new exterior opening.
We do not build accessory dwelling units (ADUs), detached guest houses, or pool houses on this scope. ADUs are a separate conversation — Florida's 2024–2025 ADU legislation introduced jurisdiction-specific rules around addressing, utility connections, and owner-occupancy that warrant a dedicated project setup, not a line-item add to a home addition.
The single highest-stakes question on a coastal addition
If your home is in a FEMA Special Flood Hazard Area — and a meaningful portion of single-family stock in Miami-Dade and coastal Broward is — the substantial improvement rule can change the project entirely. In plain language: if the cost of any improvement to the home (an addition counts) exceeds 50% of the home's pre-improvement market value, the entire structure must be brought into compliance with current flood code. That typically means raising the entire finished-floor elevation to current Base Flood Elevation plus the local freeboard — often four to six feet of new floor height on a slab-on-grade home built to a pre-current flood code.
The math gets ugly fast. A $400,000 second-story addition on a $500,000 coastal home in a flood zone hits the 50% threshold by a wide margin. The project becomes "addition plus raise the existing house plus replace the foundation system"— add $200,000–$400,000 of scope and turn a 9-month addition into a 14-month near-rebuild. Sometimes it still pencils. Sometimes the right answer is a smaller addition that stays under the threshold. Sometimes it's tear down and start over under a clean new-construction permit.
We check this on every addition project in a flood zone before we quote. The answer determines what project you are actually buying.
What a home addition costs in Miami-Dade and Broward
Six phases, end to end
Living in the home during the build
Most clients live in the home during construction. That's doable, and the discipline that makes it doable is a real cost driver worth naming. We build a temporary partition wall between the existing conditioned space and the work zone before any envelope is opened. Dust control runs on negative-pressure air scrubbers. MEP shutdowns — water off, panel de-energized, HVAC down for tie-ins — get scheduled with you in advance, not announced that morning.
Two moments are hard to stay through: the day the new construction ties into the existing structure, and final HVAC commissioning when both systems run together for balance. On second-story additions, two to four nights elsewhere during the roof tear-off is common. The rest is livable with planning.
Where we build & the license
Home additions across Miami-Dade County (full), Broward County (full), and Palm Beach County (full). HVHZ jurisdictions shape the new-portion envelope spec; coastal flood-zone work brings the FEMA 50% rule into play. We do not build outside this footprint.
Florida Certified General Contractor, license CGC1524886, verifiable at MyFloridaLicense.com. The CGC license is the credential required to pull permits for structural work — a handyman, residential, or building-contractor license cannot legally pull a structural addition permit in Florida. General liability and workers' comp certificates issue before any crew sets foot on the property.
Three additions, three project types
Project narratives are illustrative pending portfolio audit — no client identification, no named cities below the county level, no identifying details until verified.
Home addition questions
What's the difference between a home addition and a remodel?
A remodel changes what's inside the existing footprint without expanding it. An addition expands the footprint with new conditioned square footage that ties into the existing structure — new foundation or load-path retrofit, new envelope to current FBC 8th Edition and HVHZ requirements, and integration of new structure with existing. None of that applies to a remodel inside the existing shell.
Can I add a second story to my single-story home in Miami-Dade or Broward?
Usually yes, but it depends on the existing first-floor structure's ability to carry the new load and whether the lateral load path meets current HVHZ requirements. A structural engineer's review is required before scope is set. On 1960s–70s slab-on-grade homes, second stories typically need foundation reinforcement, first-floor wall reinforcement, and strapping retrofit — $40K–$120K of the budget on most homes. Rarely a deal-breaker, but it's engineered before contract.
What is the FEMA 50% rule, and how does it affect my addition in a flood zone?
The substantial improvement rule: if the cost of any improvement — including an addition — exceeds 50% of your home's pre-improvement market value, the entire home must be brought into compliance with current flood code. In coastal Miami-Dade and Broward that typically means raising the finished-floor elevation to BFE plus freeboard, four to six feet on slab-on-grade homes. It can add $200K–$400K of scope. We check the math on every flood-zone addition during feasibility, before we quote.
Do I need to move out during a home addition?
Usually no. Most clients stay for the duration. Two moments are hard: the day the existing structure opens for the tie-in, and final HVAC commissioning. On second-story additions, two to four nights elsewhere during the roof tear-off is common. The rest is livable with dust control, scheduled MEP shutdowns, and a designated work zone behind a temporary partition.
How long does a home addition take in Miami-Dade or Broward?
End to end, including engineering, permits, build, and inspections: garage conversions run 4–7 months, single-story room additions 7–11 months, second-story additions 9–15 months. Permit review varies by jurisdiction and runs 4–12 weeks. The build phase is rarely the bottleneck — engineering, permitting, and existing-conditions surprises are.
Will my existing electrical, HVAC, and plumbing handle an addition, or do I need upgrades?
Most additions trigger at least one MEP capacity upgrade. A 100-amp panel rarely supports a new load — a 200-amp upgrade adds ~$4K–$8K. A new addition usually needs its own HVAC zone or a second system because tying into an existing single-zone air handler typically fails Manual J. Plumbing is usually sufficient for one new bath; a kitchen extension sometimes needs a sewer or main-line upgrade. We verify capacity at the site visit and price upgrades into the contract, not as change orders.
Request a free site visit
Home addition feasibility starts with two to four hours on site. We measure, document, and check the substantial-improvement math on flood-zone homes before we quote. The site visit is free.
Last updated August 2026.