Permits & Regulations
The FEMA 50% rule explained
How the FEMA 50% rule works for Florida renovations and storm repairs in flood zones, how market value is set, and how to plan around it.
Project Costs
How Much Does a Home Addition Cost in Florida? (2026 Prices)
What a room addition, second-story addition or garage conversion costs in Florida per square foot, plus flood zones, impact fees and design costs.
Last updated: 2 min readBy the Florida Renovation Guide editorial teamTopic: Permits & Contractor Guides
The short answer
- Ground-floor additions in Florida typically cost about $200–$450 per square foot of new space, and second-story additions about $275–$500.
- Converting a garage to living space usually costs less, about $150–$300 per square foot, because the slab, walls and roof already exist.
- A 400 sq. ft. ground-floor addition often lands around $80,000–$180,000, before design, impact fees and any flood-zone requirements.
- In a flood zone, a large addition can trigger the FEMA 50% rule. Check before you design.
On this page
An addition is the most expensive way to get more space, but often the right one when moving would cost more or you love where you live. Florida additions have their own cost drivers: concrete block construction, hurricane codes and, in many coastal areas, flood rules.
Addition cost per square foot
| Item | Estimated range | What affects it |
|---|---|---|
| Ground-floor addition | $200–$450per sq. ft. | Includes slab foundation, concrete block or frame walls, roof and finishes. Kitchens and bathrooms push costs up. |
| Second-story addition | $275–$500per sq. ft. | Structural reinforcement, stairs and temporary weather protection. |
| Garage conversion to living space | $150–$300per sq. ft. | Uses the existing slab and roof. Raising the floor, insulation and windows add cost. |
Published Florida pricing varies widely. Contractors in Palm Beach County and Tampa quote toward the upper end for ground-floor additions, while some St. Petersburg pricing starts lower. Additions with kitchens or bathrooms cost more per square foot than bedrooms or family rooms. For Melbourne and the rest of the Space Coast, see home addition costs in Brevard County, which also covers local septic, flood zone and impact fee rules.
Example budgets
| Project | What's included | Estimated range |
|---|---|---|
| Garage conversion | 450 sq. ft. two-car garage converted to a bedroom suite | $67,500–$135,000 |
| Small room addition | 250 sq. ft. bedroom addition on a slab | $50,000–$113,000 |
| Family room addition | 400 sq. ft. ground-floor addition | $80,000–$180,000 |
| Second-story addition | 600 sq. ft. over an existing one-story home | $165,000–$300,000 |
These don't include design and engineering fees, impact or utility fees, survey costs or furniture.
Need a contractor for this project?Request a home addition estimate
What drives the price
- Kitchens and bathrooms. Plumbing on a slab means trenching and new drain lines. Wet rooms cost far more per square foot than bedrooms.
- Structure. Concrete block walls with tie beams, roof trusses and hurricane straps are standard. Second stories need the existing walls and foundation checked to carry the new load.
- Tying into the existing roof. Joining a new roof to an old one is one of the trickiest parts of an addition, and it can force a reroof of the existing house.
- Windows and doors. In the wind-borne debris region, new openings need impact-rated products or approved protection.
- Flood zones. In a FEMA flood zone, the addition may need to be elevated, and if the project's cost reaches 50% of the home's market value, the whole home may have to be brought up to flood requirements. See the FEMA 50% rule in Florida.
- Site and zoning. Setbacks, lot coverage and easements can limit what you can build. A survey comes first.
- HVAC and electrical capacity. More space may need a larger air conditioning system or a panel upgrade.
Permits and design
An addition always needs a building permit with drawings and engineering, plus zoning review. Larger projects also need a recorded Notice of Commencement. Our building permit basics explain the process.
Who should build it?
An addition needs a licensed general, building or residential contractor to manage structural work and coordinate licensed trades. Read general contractor vs. hiring trades yourself, and plan for both time and money surprises with our guides to renovation timelines and contingency budgets. Then follow our contractor hiring guide.
If your home is on a septic system, ask the health department early whether the addition needs a septic evaluation or upgrade; see septic systems, septic-to-sewer and remodeling.
Frequently asked questions
Is it cheaper to build up or out in Florida?
Building out on a slab is usually cheaper per square foot than adding a second story, which needs structural reinforcement, stairs and protection from the weather while the roof is open. But a small lot, setbacks or a flood zone can make building up the only option.
How long does a home addition take?
Design, engineering and permitting often take a few months before construction starts, and construction itself commonly takes several months. Our renovation timelines guide breaks down the stages.
Do I need an architect for an addition?
Additions need permit drawings, and structural elements need engineering. Many homeowners use an architect or a design-build contractor; smaller projects may use a residential designer working with an engineer. Ask your building department what it requires.
Does an addition increase my property taxes?
New square footage is generally added to your home's assessed value. If you have a homestead exemption, ask your county property appraiser how an addition is treated before you build.
Sources and further reading
- Home Addition Cost in Palm Beach County (2026) (South Shore Builders)
- Home Addition Cost in Tampa (2026 Pricing Guide) (NovaCore Builders)
- Home Addition Cost in St. Pete (Revolution Florida)
- Home Addition Cost Florida 2026 (Wilson Build)
- FEMA 50% rule (City of Miami Beach)
We summarize official information in our own words and link to the source. Requirements can change, so confirm details with the source before relying on them. Our editorial standards
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