Florida Building Code Roofing Requirements (2026 FBC 8th Edition)

The Florida Building Code is not a suggestion. It is the law that governs every shingle, nail, and sheet of underlayment installed on your roof. For homeowners in Pinellas County, understanding the FBC is the difference between a roof that survives a Category 4 hurricane and one that peels apart during a tropical storm.

The 2026 FBC 8th Edition, which took effect on January 1, 2026, builds on decades of hard lessons from hurricanes Andrew, Charley, Irma, Ian, and Milton. Every edition gets stricter. Every edition adds requirements that contractors in other states never have to think about. That is the price of living in one of the most hurricane-prone regions on Earth, and it is worth every penny when the wind starts howling.

This guide covers every major roofing provision in the 8th Edition that applies to residential properties in Pinellas County. Whether you are planning a roof replacement, dealing with storm damage, or just trying to understand what your contractor is talking about, this is the reference you need.

What Is the Florida Building Code 8th Edition?

The Florida Building Code (FBC) is the statewide construction standard administered by the Florida Building Commission under the Department of Business and Professional Regulation. Unlike most states where local jurisdictions can adopt different code versions, Florida mandates a single unified code for the entire state. Local amendments are allowed only under limited circumstances, and they can only be more restrictive than the base code, never less.

The 8th Edition is based on the 2021 International Building Code (IBC) and 2021 International Residential Code (IRC), but with extensive Florida-specific amendments. These amendments address hurricane resistance, high-velocity hurricane zones, moisture protection, energy efficiency in hot-humid climates, and product approval requirements that do not exist anywhere else in the country.

For roofing, the relevant sections are spread across multiple chapters:

• FBC Residential Chapter 9 (Roof Assemblies): Covers roof covering materials, application methods, underlayment, flashing, and re-roofing for single-family and two-family dwellings.
• FBC Residential Chapter 8 (Roof-Ceiling Construction): Covers structural requirements including roof deck attachment, truss bracing, gable end reinforcement, and load paths.
• FBC Building Section 1504-1511: Covers roofing for commercial and multi-family structures under the building code rather than the residential code.
• FBC Existing Building Chapter 7: Covers re-roofing, repairs, and alterations to existing structures including the 25% rule.
• Rule 61G20: Product approval requirements administered by the Florida Building Commission.

Wind Speed Zones and Exposure Categories in Florida

Wind speed is the single most important variable in Florida roofing code compliance. Every material selection, fastening schedule, and installation method ultimately traces back to the design wind speed for your specific location. The FBC uses the ASCE 7-22 wind speed maps to establish basic wind speeds across the state.

Basic Wind Speed for Pinellas County

Pinellas County falls within the 130 mph basic wind speed zone for Risk Category II structures (which includes most residential buildings). This is based on a 3-second gust speed at 33 feet above ground in Exposure C conditions. It is the starting point for all engineering calculations, but the actual design wind pressures on your roof depend on several additional factors.

For context, here is how Pinellas compares to other Florida regions:

Exposure Categories: B vs C vs D

The exposure category describes the terrain surrounding your property and directly affects the wind pressures your roof must resist. Higher exposure means wind has a longer, unobstructed path to build speed before hitting your home.

• Exposure B: Urban and suburban areas with closely spaced obstructions (buildings, trees, hills) that are at least 20 feet tall. Most inland Pinellas County neighborhoods with mature tree canopy and dense housing qualify as Exposure B. This produces the lowest wind pressures for a given wind speed.
• Exposure C: Open terrain with scattered obstructions generally less than 30 feet tall. This includes flat, open areas, shorelines of large inland bodies of water, and areas transitioning from Exposure B to D. Large portions of Pinellas County near Tampa Bay or areas with limited tree cover fall into Exposure C. This is also the default exposure category when conditions are uncertain.
• Exposure D: Flat, unobstructed areas directly exposed to open water extending at least one mile. Properties on Pinellas County barrier islands (Clearwater Beach, Indian Rocks Beach, Treasure Island, St. Pete Beach) and shoreline properties facing the Gulf of Mexico or Tampa Bay with open fetch distance of one mile or more are classified as Exposure D. This produces the highest wind pressures.

The practical difference is significant. A roof in Exposure D at 130 mph basic wind speed experiences considerably higher design pressures than the same roof in Exposure B at the same wind speed. A home on Clearwater Beach (Exposure D) might require 6-nail fastening and enhanced underlayment, while an inland home in Largo (Exposure B) at the same wind speed might comply with 4-nail fastening and standard underlayment.

Product Approval Requirements: FL Numbers and Miami-Dade NOAs

This is the requirement that makes Florida unlike any other state. Every roofing product installed in Florida must carry a valid Florida Product Approval. There are two paths to approval:

• State Product Approval (FL Number): Products tested and certified through the statewide system administered by the Florida Building Commission. Each approved product receives an FL number (for example, FL12345-R5) that can be verified on the Florida Building Commission Product Approval website. The listing specifies exactly what wind speeds, installation methods, and conditions the product is approved for.
• Miami-Dade County Notice of Acceptance (NOA): Products tested and approved through Miami-Dade County's stringent testing program. A Miami-Dade NOA is accepted statewide as an alternative to the state FL number. NOAs are particularly common for products designed for the High Velocity Hurricane Zone, and they often represent the highest level of testing in the country.

What does this mean for you as a homeowner? It means the shingles, underlayment, flashing, ridge vent, and every other component your contractor installs must have a valid, current approval number. Expired approvals do not count. Products approved for one installation method cannot be installed using a different method. A shingle approved for 4-nail installation at 110 mph cannot be used at 130 mph unless the approval also covers that wind speed with the appropriate fastening pattern.

Your contractor should provide product approval documentation as part of the permit application. The building inspector will verify that the products installed match the approved products listed on the permit. Mismatches result in failed inspections.

Fastening Schedules: 4-Nail vs 6-Nail Patterns

How shingles are nailed to the roof deck is one of the most critical details in Florida roofing. The FBC specifies minimum fastening requirements based on wind speed and the specific product approval, and getting this wrong is one of the most common reasons for roof failures during hurricanes.

Standard 4-Nail Pattern

The 4-nail pattern places fasteners at four designated points along the shingle nailing strip. This is the minimum pattern allowed by most shingle manufacturers for their standard warranty and is acceptable under the FBC in lower wind speed zones (typically 110 mph and below) or in Exposure B conditions in some moderate wind speed zones.

Enhanced 6-Nail Pattern (High Wind)

The 6-nail pattern adds two additional fasteners for a total of six per shingle. In Pinellas County at 130 mph, the 6-nail pattern is required for most asphalt shingle products in Exposure C and Exposure D conditions. Even in Exposure B, many product approvals require 6 nails at 130 mph.

The difference in wind resistance is substantial. Testing data consistently shows that 6-nail installations resist 20-40% higher uplift pressures than 4-nail installations with the same shingle. During Hurricane Ian, post-storm assessments found that roofs installed with proper 6-nail patterns in the 130 mph zone survived at dramatically higher rates than those with 4-nail patterns.

Nail Placement and Depth

Beyond the number of nails, the FBC and manufacturer specifications require precise nail placement. Nails must be driven into the designated nailing strip, typically 5/8 inch to 1 inch above the cutout slots. Nails placed too high miss the overlap and provide minimal holding power. Nails placed too low can crack the shingle or miss the underlying course.

Nail depth matters equally. Nails must be driven flush with the shingle surface. Overdriven nails (driven too deep) tear through the mat and lose holding power. Underdriven nails (protruding above the surface) create bumps that prevent the next course from sealing properly. Both conditions compromise wind resistance and can lead to inspection failures.

Underlayment Requirements

Underlayment is the water-resistant barrier installed between the roof deck and the roof covering. The FBC has specific underlayment requirements that vary by location and roof type, and they are significantly more stringent than the base IRC.

Standard Underlayment (Non-HVHZ Areas Including Pinellas)

For areas outside the High Velocity Hurricane Zone (which includes all of Pinellas County), the FBC requires:

• Minimum one layer of ASTM D226 Type II (#30) asphalt-saturated felt, or an approved synthetic underlayment meeting ASTM D226 equivalency.
• Enhanced underlayment at eaves: A minimum of one layer of self-adhering polymer-modified bitumen underlayment (peel-and-stick) must be installed from the eave edge extending up the roof to at least 24 inches past the interior wall line. This ice-and-water shield equivalent protects against wind-driven rain intrusion at the most vulnerable roof edge.
• Valleys: A minimum of one layer of self-adhering underlayment in all valleys, extending at least 24 inches on each side of the valley centerline.

HVHZ Underlayment Requirements (Miami-Dade and Broward)

While Pinellas County is not in the HVHZ, understanding these requirements provides context for how Florida approaches roofing in extreme wind zones:

• Full self-adhering underlayment over the entire roof deck (not just at eaves and valleys).
• Products must carry a Miami-Dade NOA for the specific application.
• Mechanical fastening alone is not acceptable for underlayment in the HVHZ.

For more details on underlayment types and installation, see our dedicated guide.

Re-Roofing Provisions: The 25% Rule and Maximum Layers

The FBC Existing Building Code Chapter 7 governs what happens when you need to replace or repair an existing roof. These provisions determine whether you can add a new layer over the existing one (re-cover) or must strip everything down to the deck (full replacement).

Maximum Two Layers

The code permits a maximum of two layers of asphalt shingles on a residential roof. If your home already has two layers, any re-roofing work requires a complete tear-off. No exceptions. Three layers of shingles add excessive weight to the roof structure, trap moisture between layers (accelerating deck rot), and make it impossible to inspect the deck for damage.

The 25% Rule (Section 706.1.1)

This is one of the most significant provisions in the Florida re-roofing code and the one that catches homeowners off guard most frequently. The rule states:

If more than 25% of the total roof area is repaired, replaced, or recovered within any 12-month period, the entire roofing system must be brought into compliance with the current edition of the Florida Building Code.

In practical terms, this means that if hurricane damage affects more than a quarter of your roof, you cannot simply patch the damaged section and leave the rest. The entire roof must be stripped and replaced to current code standards. This includes current underlayment requirements, current fastening schedules, current product approvals, and current wind resistance standards.

The 25% threshold applies cumulatively over a rolling 12-month window. A contractor cannot legally do 20% now and another 20% three months later to avoid triggering the full replacement requirement. Building departments track permits, and this type of staged work to circumvent the code is a violation.

Gable End Bracing Requirements (R802.11.1)

Gable end walls are one of the most vulnerable structural elements during a hurricane. When wind pressures push against the flat face of an unbraced gable end, it can collapse inward, leading to catastrophic roof failure. The FBC addresses this through Section R802.11.1 and related provisions.

The code requires that gable end walls be braced to resist the lateral wind loads for the design wind speed. For new construction and for re-roofing projects that trigger the 25% rule (requiring full code compliance), the following gable end bracing standards apply:

• Gable end trusses or rafters must be braced with horizontal members (typically 2x4 lumber) running perpendicular to the gable wall at no more than 4 feet on center from the bottom of the gable to the ridge.
• Bracing connections must use approved metal connectors (not just toenailing) to transfer lateral loads to the roof diaphragm and ultimately to the foundation.
• Gable end sheathing must be attached to gable framing with enhanced nailing schedules (typically 6 inches on center at edges, 6 inches on center in the field for 130 mph zones).
• Retrofit bracing is required under certain circumstances, particularly when re-roofing triggers the 25% threshold. While the code allows some flexibility in retrofit methods, the engineering intent is clear: unbraced gable ends in high-wind zones are unacceptable.

During Hurricane Charley (2004), unbraced gable end failures were identified as one of the primary causes of total roof loss. The bracing requirements added in subsequent FBC editions directly address this vulnerability. If your home was built before 2002 and has unbraced gable ends, a re-roofing project is an opportunity to address this critical weakness.

Roof Deck Attachment Schedules

The roof deck (typically plywood or OSB sheathing) is the structural base that everything else attaches to. If the deck detaches from the trusses or rafters, nothing above it matters. The FBC specifies deck attachment schedules based on wind speed and building geometry.

Nailing Schedules for Roof Sheathing

For Pinellas County at 130 mph, the standard requirement is 8d ring-shank nails at 4 inches on center along panel edges and 6 inches on center in the field. Ring-shank nails are critical because their ridged shank provides 40-60% greater withdrawal resistance than smooth-shank nails of the same size. The FBC does not allow smooth-shank nails for roof deck attachment in the 130 mph zone.

Alternative enhanced deck attachment systems include:

• AFG-01 (Structural adhesive): Applying a bead of AFG-01 polyurethane adhesive between the deck panels and framing members, combined with the required nailing schedule. This is the gold standard for deck attachment and can increase uplift resistance by 200% or more. Many wind mitigation inspectors specifically look for this.
• Deck screws: Using approved deck screws instead of nails. Screws provide superior withdrawal resistance and are increasingly recommended for re-roofing projects where the existing deck is being retained.

Deck Attachment and Insurance

Your roof deck attachment method directly affects your homeowner's insurance premium through the wind mitigation inspection. The OIR-B1-1802 form (Florida's standardized wind mitigation form) asks the inspector to identify the deck attachment method. Properties with enhanced deck attachment (such as 8d ring-shank at close spacing or structural adhesive) receive meaningful premium discounts compared to properties with standard smooth-shank nailing at wider spacing.

Drip Edge Requirements

Drip edge is the metal flashing installed along the eaves and rakes (gable edges) of the roof. The FBC requires drip edge on all roof installations, and the requirements are more specific than many homeowners or even contractors realize.

• Material: Minimum 26-gauge galvanized steel, aluminum, or other approved corrosion-resistant material. In coastal Pinellas County locations, aluminum is recommended to prevent corrosion from salt air.
• Profile: Must extend at least 2 inches back from the roof edge on the deck surface and at least 1.5 inches down from the edge on the fascia side.
• Fastening: Drip edge must be fastened with roofing nails at no more than 12 inches on center (tighter spacing in high-wind areas).
• Installation sequence at eaves: Drip edge goes under the underlayment at the eave so water flowing down the underlayment drains over the drip edge and into the gutter.
• Installation sequence at rakes: Drip edge goes over the underlayment at the rake edges so wind-driven rain does not blow under the drip edge and behind the underlayment.

This eave-under, rake-over installation sequence is specified in the FBC and is one of the details that inspectors check. Getting it backward allows water infiltration that can rot the deck edges and fascia.

FBC vs IRC: Key Differences for Roofing

If you have ever researched roofing online, you have likely encountered advice based on the International Residential Code. While the FBC is based on the IRC, the Florida-specific amendments create significant differences that make generic IRC advice potentially dangerous for Florida homeowners.

The bottom line is that the FBC is substantially more demanding than the base IRC in virtually every category related to wind resistance. A roof that is "code compliant" in Georgia, the Carolinas, or even north Florida at lower wind speeds would fail inspection in Pinellas County. Always verify that any roofing advice you follow is specific to the Florida Building Code and your local wind speed zone.

Wind-Borne Debris Region Requirements

Pinellas County is located within the Wind-Borne Debris Region as defined by the FBC. This designation applies to areas where the basic wind speed is 130 mph or greater, as well as certain areas within one mile of the coast where wind speeds are 110 mph or greater. Being in the Wind-Borne Debris Region triggers additional requirements beyond the standard wind speed provisions:

• Impact-resistant openings: All exterior openings (windows, doors, garage doors) must be protected with impact-resistant glazing or approved shutters. While this is not a roofing requirement per se, it relates to the overall building envelope that keeps internal pressurization from blowing your roof off from the inside.
• Enhanced roof covering: Roof coverings in the Wind-Borne Debris Region must meet enhanced testing standards for impact resistance and wind uplift.
• Continuous load path: The entire structural system from roof to foundation must have a continuous load path using approved connectors (hurricane straps, clips, or ties at every connection point).

Roof Ventilation and Energy Code

While less dramatic than wind resistance requirements, the FBC also mandates proper roof ventilation and energy performance:

• Minimum ventilation: 1 square foot of net free ventilating area for every 150 square feet of attic floor area, reduced to 1:300 with a proper balance of intake and exhaust ventilation.
• Ridge vents: Must be Florida Product Approved and tested for the design wind speed. Non-approved ridge vents are a common cause of water intrusion during hurricanes because they can be ripped off or allow horizontal rain penetration.
• Reflective roofing: The Florida Energy Conservation Code (part of the FBC) encourages or requires cool roof coatings and reflective materials, particularly for low-slope roofing. For steep-slope residential, lighter-colored shingles and reflective underlayment contribute to energy compliance.

Inspection Requirements

Every permitted roofing project in Pinellas County requires inspections at specific stages. The typical inspection sequence for a residential re-roofing project includes:

1. Pre-cover inspection (dry-in): After the old roof is removed (if applicable), the deck is inspected and repaired, underlayment is installed, and drip edge and flashing are in place. The inspector verifies deck condition, deck attachment, underlayment type and installation, and flashing details before any roof covering is installed. This is the most critical inspection.
2. Final inspection: After all roof covering, ridge caps, vents, and trim are installed. The inspector verifies the completed installation against the approved product specifications and permit documents.

Failing to call for inspections, covering work before the pre-cover inspection, or proceeding after a failed inspection are code violations that can result in stop-work orders, fines, and requirements to remove completed work for re-inspection.

Common Code Violations in Pinellas County

Based on building department records and inspector reports, these are the most frequent roofing code violations found in Pinellas County:

• Insufficient fastening: Using 4-nail patterns where 6 nails are required, or placing nails outside the designated nailing zone.
• Unapproved products: Installing shingles, underlayment, or accessories without valid Florida Product Approvals, or using products approved for a lower wind speed than required.
• Missing self-adhering underlayment: Failing to install peel-and-stick at eaves or valleys where the code requires it.
• Improper drip edge installation: Installing drip edge over the underlayment at the eave instead of under it, or omitting drip edge entirely.
• Deck attachment deficiencies: Using smooth-shank nails instead of ring-shank, or nailing at wider spacing than allowed.
• Permit avoidance: Performing re-roofing work without pulling a permit, which is particularly common with storm damage repairs that homeowners attempt to handle quickly.
• 25% rule evasion: Staging roof work in phases to stay below the 25% threshold and avoid triggering full code compliance.

What This Means for Your Roofing Project

If you are planning a roof replacement in Pinellas County, here is the practical summary of what the 2026 FBC 8th Edition requires:

1. Hire a licensed Florida roofing contractor who holds a current state roofing license (CCC or CC prefix). Verify the license through the DBPR website.
2. Obtain a building permit before any work begins. Your contractor should handle this, and the permit application should include product approval numbers for all materials.
3. Use only Florida-approved products with valid FL numbers or Miami-Dade NOAs rated for your specific wind speed and exposure category.
4. Require 6-nail installation for asphalt shingles in Exposure C and D. Even in Exposure B at 130 mph, confirm with the product approval that 4-nail is actually sufficient.
5. Install self-adhering underlayment at all eaves and valleys, with a minimum of ASTM D226 Type II felt or approved synthetic over the remaining deck.
6. Verify deck attachment meets the 130 mph nailing schedule (8d ring-shank at 4"/6"). If your existing deck is under-nailed, it must be brought into compliance.
7. Call for inspections at the pre-cover (dry-in) stage and final stage. Do not allow your contractor to skip the pre-cover inspection.

Frequently Asked Questions

What wind speed is Pinellas County designed for under the Florida Building Code?

Pinellas County has a basic wind speed of 130 mph under the 2026 FBC 8th Edition for Risk Category II structures (most residential buildings). Properties on barrier islands and near the Gulf coast may have higher effective design pressures due to Exposure D classification, even though the base wind speed remains the same.

How many layers of shingles are allowed in Florida?

The Florida Building Code allows a maximum of two layers of asphalt shingles. If your roof already has two layers, a complete tear-off to the deck is mandatory before any new roofing can be installed. Even with one existing layer, the code requires that the existing layer be in reasonably good condition and that the deck can support the additional weight.

What is a Florida Product Approval number and why does it matter?

A Florida Product Approval (FL number) certifies that a roofing product has been tested and approved for use under the Florida Building Code. Every roofing material, from shingles to ridge vents, must carry a valid FL number or a Miami-Dade County Notice of Acceptance (NOA). Products without current approval cannot legally be installed in Florida. The approval specifies exactly what wind speeds, installation methods, and conditions the product is rated for.

Is the Florida Building Code the same as the International Residential Code?

No. While the FBC is based on the IRC and IBC, it includes hundreds of Florida-specific amendments that make it significantly more stringent. Key differences include mandatory product approvals, enhanced fastening schedules, self-adhering underlayment requirements at eaves and valleys, the 25% re-roofing rule, and gable end bracing requirements. Roofing advice based on the base IRC may be insufficient or incorrect for Florida installations.

Do I need a permit to re-roof my home in Pinellas County?

Yes. All roofing work in Pinellas County requires a building permit, including full replacements, re-covers, and any repairs beyond minor patching. Working without a permit is a code violation that can result in fines, and unpermitted work creates serious problems when you try to sell your home or file an insurance claim.

What is the 25% rule for roof replacement in Florida?

Under FBC Existing Building Code Section 706.1.1, if repairs or re-roofing affect more than 25% of the total roof area within any 12-month period, the entire roof must be brought into full compliance with the current Florida Building Code. This typically means a complete tear-off and replacement rather than patching. The rule ensures that roofs receiving substantial work meet current wind resistance and installation standards.

Related Resources

• Complete Roofing Guide for Pinellas County
• Roof Wind Ratings Explained
• Roof Underlayment Types and Requirements
• Roofing Permits in Florida: Complete Guide
• Hurricane Roof Damage: What to Do Next