The rule as the City writes it
| Point | City of Miami |
|---|---|
| Threshold | Cost that "equals or exceeds, over a two-year period, a cumulative total of 50 percent of the market value of the structure" |
| Market value | The structure only, excluding land and site improvements |
| Accepted values | Independent appraisal of actual cash value; tax assessment adjusted by a Property Appraiser factor; the building-only assessed value on the Miami-Dade Property Appraiser site; or a Florida-licensed USPAP appraisal under six months old |
| After a storm | The structure's value before the damage |
| Documents | Fully executed AIA owner-contractor agreement or equivalent with a detailed cost breakdown, "no exclusions"; affidavit from the architect of record (not the owner) that the contract covers the full scope |
| Over the line | Designated a Substantial Improvement; must comply with FEMA rules, the City ordinance and the Florida Building Code |
| Unrealistic numbers | The City may reject costs, ask for a second appraisal, and act against licensees through DBPR |
The City's flood page puts the consequence plainly: a house "damaged and/or improved to an amount greater than 50% of its market value" must be raised to current elevation if its elevation certificate shows it is below. Elevation certificates are required for new construction and substantial improvements, and the City has collected them with permits since 1995.
What it means when you hire
- Price the whole job, once. The contract must show the full scope with no exclusions. Splitting a kitchen, a roof and an addition across separate permits does not help: the two-year total adds them.
- Find the building value before you design. Open the Miami-Dade Property Appraiser record and note the building value, not the total. Half of that number is your two-year budget before the review changes the project.
- Ask for the elevation certificate. Homes permitted after 1995 should have one on file with the City; older homes may need a surveyor. If the house is already at or above the required elevation, the elevation consequence falls away.
- Use a firm used to the review. The architect signs the affidavit and the contractor signs the contract; the City says inflated or deflated numbers can lead to DBPR action. Check the firm's license on DBPR: 90.9% of remodel firms and 96.4% of addition firms on City permits matched an active license.
- Check past permits on the address. In iBuild, list the address's permits from the last two years; their values count toward the total.
What City of Miami remodel and addition permits show
| Measure | Remodel & repair | Addition & remodel |
|---|---|---|
| Permits on homes, October 2023 to September 2026 | 3,752 | 936 |
| Firms | 1,475 | 503 |
| Usual filed value | $15,000 | $38,564 |
| Middle half of firms' usual value | $9,500 to $35,525 | $10,000 to $55,000 |
| Reached Final (a year or more old) | 92.8% | 73.4% |
| Usual days from issue to Final | 182 | 313 |
| Firms with exactly one permit | 55.6% | 57.1% |
Additions take longer and close less often: 73.4% reached Final against 92.8% for remodels, in a usual 313 days. More than half of firms in both lists filed just one permit, so ask any firm how many substantial improvement reviews it has been through. Prices by firm: Miami remodel cost and Miami addition cost; counts by year: Miami permit statistics.
Compare City of Miami addition contractors →
Related
Permit steps and fees: Miami remodel permit. Older permits on a house: Miami building permit search. Checking a license: Miami contractor license lookup. The remodeler list ranks firms by permits at Final.
What this does not tell you
Our records do not show flood zones, elevation certificates or which permits were reviewed as substantial improvements. The City's policy is dated May 2021; confirm current practice with the Building Department ((305) 416-1140, on the City's flood page). We cover the City of Miami only; Miami Beach and other cities run their own reviews.
How we know this
The threshold, valuation methods and documents are from the City of Miami Building Department's official policy "Establishing values for FEMA regulations" (v7, 18 May 2021); the elevation consequence and certificate history from the City's Hurricane Flood Information page, both read 23 October 2026. Permit counts are City of Miami building permits on homes classified as remodel/repair or addition, October 2023 to September 2026; Final share uses permits a year or more old.
Numbers come from City of Miami building permits (since 2014), data through October 17, 2026. Nobody paid to be on this page and nobody can.
Questions
- What is the 50% rule in Miami?
If a house in a flood zone is improved or repaired for 50% or more of the structure's market value, the City of Miami treats it as a substantial improvement, and the house must meet current flood rules; the City's flood page says it must be raised to current elevation if it sits below it.
- Is the Miami 50% rule cumulative?
Yes. The City's 2021 valuation policy counts improvements whose cost 'equals or exceeds, over a two-year period, a cumulative total of 50 percent of the market value of the structure.' Permits filed within two years add together.
- How does the City of Miami decide my home's value for the 50% rule?
It uses the structure only, not the land. Accepted values include the building-only assessed value on the Miami-Dade Property Appraiser site, or a Florida-licensed USPAP appraisal less than six months old; after a storm, the value before the damage.
- What documents does Miami require for a substantial improvement review?
A fully executed AIA owner-contractor agreement or an equivalent contract with a detailed cost breakdown showing the full scope with no exclusions, plus an affidavit from the architect of record that the contract sum covers the whole scope on the plans.
- How much do remodels usually cost in Miami?
City of Miami remodel and repair permits were usually filed at $15,000 and additions at $38,564, October 2023 to September 2026.
Build your own list
Every firm with that kind of permit on record. Pick what you value. The list moves.
Related guides
- How to legalize unpermitted work: the steps, what it costs, and how long a retroactive permit takes
- Boulder's demolition review for houses over 50 years old: what counts as demolition, the fees, and the 180-day stay
- Greensboro historic district rules: the COA for College Hill, Dunleath and Fisher Park, and how it changes hiring
- Naperville historic district rules: Fast Track vs Commission COAs, and what each costs you in time
- Do I need a permit for a home addition in Miami? Yes: plan review, owner-builder limits, the square-foot surcharge and timing
- Do I need a remodel permit in Miami? Cabinets, the $7,500 exemption, owner-builders, fees and sub-permits
For one city
- Official Policy: Establishing values for FEMA regulations — City of Miami Building Department (v7) (2021-05-18, accessed 2026-10-23)
- Hurricane Flood Information — City of Miami (accessed 2026-10-23)
- View Permit History / Permit Search — City of Miami (accessed 2026-10-23)
- Verify a Licensee — Florida DBPR Online Services (2026-10-22)