Florida building code roof requirements come down to two rules that decide most reroof jobs in the state: the 25 percent rule in Section 706.1.1 of the Florida Building Code, Existing Building, and the secondary water barrier that has to go down whenever a roof covering is removed. Both were rewritten after 2022, and a large share of the pages explaining them still quote the pre-2022 text.
By The Roofing Brief Team. Last reviewed: August 2026. Code text in this article was read from the 8th Edition (2023) Florida Building Code and the 2025 Florida Statutes on 15 August 2026.
What the 25 percent rule actually says
Section 706.1.1 of the Florida Building Code, Existing Building reads: “Not more than 25 percent of the total roof area or roof section of any existing building or structure shall be repaired, replaced or recovered in any 12-month period unless the roof covering on the entire existing roof system or roof section is replaced or recovered to conform to the requirements of this code.” The trigger is cumulative across 12 months, not per job.
Two words carry most of the weight. “Roof section” narrows the denominator, so the 25 percent is often measured against one plane rather than the whole house. “In any 12-month period” means three separate 10 percent repairs inside a year add up and cross the line.
The rule sits in the Existing Building code, not the Building code. That placement matters because the mitigation requirements discussed further down live in the same chapter and are frequently quoted as though they were part of the 25 percent rule itself.
The 2007 code exception that changed the rule
An exception now sits directly under 706.1.1, and it is the single most misdescribed part of Florida building code roof requirements. Verbatim: “If an existing roofing system or roof section was built, repaired, or replaced in compliance with the requirements of the 2007 Florida Building Code, or any subsequent editions of the Florida Building Code, and 25 percent or more of such roofing system or roof section is being repaired, replaced, or recovered, only the repaired, replaced, or recovered portion is required to be constructed in accordance with the Florida Building Code in effect, as applicable.”
The exception traces to Senate Bill 4-D, passed in the May 2022 special session, which added subsection (5) to section 553.844 of the Florida Statutes. The same subsection (5) text appears in the 2025 Florida Statutes as published by the Florida Senate, so the exception is current law as of August 2026, not a proposal.
The code adds a sentence that gets left out almost everywhere: “Pursuant to s. 553.844(5), Florida Statutes, a local government may not adopt by ordinance an administrative or technical amendment to this exception.” A county or city cannot write a stricter local version of it.
Analyses of the amendment, including those published by J.S. Held and the law firm Jimerson Birr, use 1 March 2009 as the practical dividing line, because that is the date the 2007 edition took effect. A roof built or last replaced under a permit issued after that date is generally in exception territory, though the code condition is compliance with the 2007 edition or later, not the permit date alone.
| Roof section built or last replaced | Portion repaired or replaced in any 12 months | What the code requires |
|---|---|---|
| Before the 2007 edition (in practice, permitted before 1 March 2009) | 25 percent or less | Only the repaired area has to meet current code |
| Before the 2007 edition | More than 25 percent | The entire roof system or roof section has to be replaced or recovered to current code |
| Under the 2007 edition or later, in compliance | 25 percent or more | Only the repaired, replaced or recovered portion has to meet current code (706.1.1 exception) |
What counts as a roof section
The Florida Building Code, Existing Building defines a roof section as “a separating or division of a roof area by existing expansion joints, parapet walls, flashing (excluding valley), difference of elevation (excluding hips and ridges), roof type or legal description.” That definition decides whether a repair is 40 percent of a small plane or 8 percent of a whole roof.
Read the exclusions closely. Valleys, hips and ridges do not create a section boundary, which is where most homeowner-facing explanations go wrong. A change in roof type, for example a tile main roof with a low-slope membrane over a lanai, does create one, and so does a difference in elevation.
Because the definition leans on physical breaks rather than geometry, a simple hip roof on a Florida ranch house is usually one section. Damage on the rear slope is therefore measured against the whole roof, not against that slope alone.
Secondary water barrier requirements on a Florida reroof
Section 706.7.2 of the Existing Building code requires that when a roof covering is removed and replaced, a secondary water barrier be installed in accordance with Section 1507.1.1 or 1518.2 of the Florida Building Code, Building, or Section R905.1.1 of the Florida Building Code, Residential. Roof slopes below 2:12 with a continuous system, and clay and concrete tile installed to code, are excepted.
Section 1518 is the High-Velocity Hurricane Zone chapter, which applies in Miami-Dade and Broward counties. Section 1507.1.1 covers the rest of the state. In the 8th Edition the two paths list the same three compliance methods, at 1507.1.1.1 and 1518.2.1 respectively, so the practical difference on a steep-slope reroof is smaller than the HVHZ reputation suggests.
| Method | What goes on the deck | Standard cited in the code |
|---|---|---|
| 1 | Entire roof deck covered with an approved self-adhering polymer modified bitumen underlayment | ASTM D1970 |
| 2 | Minimum 3 3/4 inch wide self-adhered strip over every joint in the roof decking, then an approved underlayment over the whole roof | ASTM D1970, or AAMA 711 Level 3 flashing tape rated to 176F |
| 3 | Two layers of underlayment in half-lapped courses, fastened with annular ring or deformed shank cap nails | ASTM D226 Type II, ASTM D4869 Type III or IV, or ASTM D8257 |
Method 3 carries fastening detail worth pricing before you bid: cap nails at a maximum of 12 inches on center between side laps and 6 inches on center at end and side laps, caps not less than 1 inch nominal diameter, and metal caps rather than plastic where the ultimate design wind speed reaches 170 mph. Our guide to underlayment slope requirements covers how the 2:12 threshold changes the assembly.
Both 1507.1.1.1 and 1518.2.1 include an exception for a self-adhering modified bitumen underlayment already on the deck: if it can be confirmed, and deck renailing under Section 706.7.1 can be verified where required, an approved underlayment may go over the existing membrane instead of stripping it.
Foam adhesive is a deck attachment method, not a water barrier
Spray foam adhesive appears in the Existing Building code at Section 706.7.1.2, as an alternative for wood structural panel connections, not as a secondary water barrier. The code deems a “two part urethane based closed cell adhesive sprayed onto the joint between the sheathing and framing members” compliant where testing on panels connected with 6d smooth shank nails at 6 inch edge and 12 inch field spacing shows uplift resistance of at least 200 psf.
The confusion is understandable, because Florida’s uniform mitigation inspection form and several insurer credit programs treat a foam barrier and a self-adhered membrane as adjacent items. For permit purposes they answer different code sections. Foam under the deck does not satisfy 706.7.2, and a peel and stick membrane on top does not satisfy 706.7.1.
How the deck renailing requirement interacts
Section 706.7.1 governs deck fastening when a covering is removed and replaced on a structure with a sawn lumber, wood plank or wood structural panel deck. Sawn lumber or plank decking up to 12 inches wide with at least two 8d nails into every framing member is deemed sufficiently connected. For wood structural panels, Table 706.7.1.2 sets the supplemental fastener spacing.
| Existing fasteners | Existing spacing | Vasd 110 mph or less | Vasd above 110 mph |
|---|---|---|---|
| Staples or 6d | Any | Supplemental fasteners at 6 inches o.c. | 6 inches o.c. |
| 8d clipped head, round head, smooth or ring shank | 6 inches o.c. or less | None necessary | None necessary |
| 8d clipped head, round head, smooth or ring shank | Greater than 6 inches o.c. | 6 inches o.c. | 6 inches o.c. |
Supplemental fasteners have to be ASTM F1667 classification RSRS-01 ring shank nails: 0.113 inch nominal shank, ring diameter at least 0.010 inch over the shank, 16 to 20 rings per inch, a full round head of at least 0.280 inch, ring shank extending at least 1 1/2 inches from the tip, and a minimum length of 2 3/8 inches. The IRC roof deck fastening requirements differ from these Florida retrofit numbers, so do not carry one set into the other.
Sequence matters on the job. Renailing happens on the bare deck, the secondary water barrier goes over it, and an inspection usually sits between the two. Scheduling the barrier before the deck inspection is a common cause of a failed reroof inspection in Florida.
Who is exempt from the mitigation sections
Sections 706.7 and 706.8 both carry the same exception: “Structures permitted subject to the Florida Building Code are not required to comply with this section.” Buildings originally permitted under the Florida Building Code, which took statewide effect in 2002, sit outside these retrofit requirements. The mitigation package is aimed at older, pre-code housing stock.
Section 706.8 adds a separate threshold. In the wind-borne debris region, a reroof on a building with an insured value of $300,000 or more, or a just valuation of $300,000 or more for ad valorem purposes where no insured value is documented, triggers roof-to-wall connection improvements under 706.8.1. Those mandated retrofits are capped: they “shall not be required beyond a 15 percent increase in the cost of reroofing.”
In the HVHZ, product selection is the other half of compliance. Assemblies generally need a Miami-Dade Notice of Acceptance or a Florida Product Approval, which we cover in detail in our guide to the Miami-Dade NOA roofing approval process. The 25 percent rule tells you how much of the roof has to be brought up to code; product approval tells you what you are allowed to install on it.
Which edition applies to your permit
The 8th Edition (2023) Florida Building Code took effect on 31 December 2023, per the Florida Building Commission, and governs permit applications through 30 December 2026. The 9th Edition (2026) is scheduled to take effect on 31 December 2026. Every section number quoted in this article is from the 8th Edition.
For roofing, the published 9th Edition changes concentrate on Section 706.3, recovering versus replacement. The Florida Roofing and Sheet Metal Contractors Association reports new language allowing existing insulation or lightweight insulating concrete to stay in place when the upper of two roof systems is removed, and permitting an existing vapor barrier or self-adhering membrane adhered to the deck to remain. Exception 3 in the 8th Edition currently reads “Reserved,” which is the slot that language fills.
Permits applied for and issued before the changeover are generally worked under the edition in effect at application. If a job straddles late December 2026, the application date is the number to protect. Licensing and code adoption vary widely by state, which we track in our 2026 state roofing code and licensing report.
What gets people in trouble
- Treating the exception as automatic. The exception requires the existing roof to have been built, repaired or replaced in compliance with the 2007 edition or later. A 2015 roof installed without a permit does not qualify simply because of its age.
- Measuring against the wrong denominator. Valleys, hips and ridges do not divide a roof into sections. Using them inflates the percentage and forces an unnecessary full replacement.
- Stacking repairs inside 12 months. Two 15 percent repairs in the same year cross the threshold even though neither does alone.
- Assuming HVHZ rules are unique. On steep-slope reroofs the three secondary water barrier methods at 1518.2.1 mirror those at 1507.1.1.1.
- Letting an unlicensed crew pull the permit. Florida licensing rules are enforced separately from the code, and are covered in our guide to the Florida roofing contractor license.
Frequently asked questions
What is the 25 percent rule for roofs in Florida?
Section 706.1.1 of the Florida Building Code, Existing Building says no more than 25 percent of a roof area or roof section may be repaired, replaced or recovered in any 12-month period unless the covering on the entire roof system or section is brought to current code. The threshold is cumulative over 12 months, so separate small repairs can combine to trigger it.
Does the 25 percent rule still apply in 2026?
Yes, the rule remains in the 8th Edition (2023) code, but an exception added by Senate Bill 4-D in 2022 limits it. Where a roof system or section was built, repaired or replaced in compliance with the 2007 Florida Building Code or later, only the repaired portion must meet current code. That exception appears in section 553.844(5), Florida Statutes, current as of the 2025 statutes.
What counts as a roof section under the Florida Building Code?
The Existing Building code defines a roof section as a division of roof area by existing expansion joints, parapet walls, flashing excluding valleys, a difference of elevation excluding hips and ridges, roof type or legal description. Hips, ridges and valleys do not create separate sections, so a straightforward hip roof is usually treated as a single section for the 25 percent calculation.
Is a secondary water barrier required on every Florida reroof?
Section 706.7.2 requires a secondary water barrier whenever a roof covering is removed and replaced, installed per Section 1507.1.1 or 1518.2 of the Building code or R905.1.1 of the Residential code. Exceptions cover slopes under 2:12 with a continuous system and code-compliant clay and concrete tile. Structures originally permitted under the Florida Building Code are exempt from Section 706.7 entirely.
Does peel and stick underlayment satisfy the secondary water barrier requirement?
Full deck coverage with an approved self-adhering polymer modified bitumen underlayment complying with ASTM D1970 is the first of three listed methods, so yes, when the product is approved and installed to both the underlayment and roof covering manufacturer instructions. Taped deck joints under an approved underlayment, and a two-layer felt-type system with cap nails, are the other two accepted methods.
Which edition of the Florida Building Code applies to my roof permit?
The 8th Edition (2023) took effect 31 December 2023 and governs permit applications through 30 December 2026. The 9th Edition (2026) is scheduled to take effect 31 December 2026, with roofing changes concentrated in Section 706.3 on recovering versus replacement. Permits applied for and issued before the changeover are generally worked under the edition in effect at application.
Sources
- Florida Building Code, Existing Building, 8th Edition (2023), Sections 706.1.1, 706.3, 706.5, 706.7, 706.7.1, 706.7.1.1, 706.7.1.2, Table 706.7.1.2, 706.7.2, 706.8, 706.8.1, and Chapter 2 definitions.
- Florida Building Code, Building, 8th Edition (2023), Sections 1507.1.1, 1507.1.1.1, Table 1507.1.1.1, 1518.2 and 1518.2.1.
- Section 553.844, Florida Statutes (2025), subsections (2)(b) and (5), as published by the Florida Senate.
- Florida Building Commission, floridabuilding.org: effective date of the 8th Edition (2023).
- Florida Roofing and Sheet Metal Contractors Association, changes in the 9th Edition (2026) Florida Building Code.
- J.S. Held and Jimerson Birr analyses of the Senate Bill 4-D amendment to the 25 percent rule.