Methodology and data sources

Cost model

The cost calculator, the material comparison and the cost examples on our guides all use the same model. Prices are 2026 dollars per roofing square (100 sq ft of roof surface), with Tampa Bay outside the high-velocity hurricane zone (HVHZ) as the baseline.

Where the base prices come from

• Permit records (primary). Miami-Dade County re-roof permits issued October 2024 to October 2026 give declared job value per square foot of roof area for 5,305 single-family re-roofs (shingle median $6.96/sq ft, n=641; tile $11.20, n=836; metal $12.12, n=1,513; flat $8.99, n=2,308). City of Cape Coral permits applied for January 2025 to October 2026 give total job values for 2,217 residential re-roofs, and $543 per square for the 61 shingle permits that state the number of squares.
• Labor. BLS mean hourly wages for roofers (May 2025) by metro area.
• Price trends. BLS producer price indexes for asphalt roofing (+3.9% year over year to August 2026) and steel mill products (+23.4%), a GAF price increase notice (+6–9% from June 1, 2026), and trade-press reports on 2025 steel tariffs.
• Cross-checks only. Published cost guides (This Old House/RSMeans, HomeAdvisor, Fixr, RoofingCalc, Remodeling Cost vs. Value) and Verisk's 2025 national average replacement cost of $17,631. These are not used to set prices.

Declared permit values are self-reported and can leave out deck repairs or change orders, so we treat them as a floor-to-typical anchor, not a ceiling.

Formula

1. Roof area. Squares = footprint × slope factor × (1 + 7% overhang allowance) ÷ 100. Slope factor = √(1 + (rise/12)²). Each pitch button uses a representative rise: flat 0.5/12, low 4/12, medium 6/12, steep 8/12, very steep 11/12.
2. Footprint. From the building-footprint lookup, from your own measurement, or from living area: living area ÷ stories, plus 25% for the garage and covered porches under the main roof (an estimate). For matched addresses the calculator starts from county living area, because aerial building outlines in Manatee and Charlotte run a median 1.6× living area: they often include screened pool cages and lanais that aren't roofed.
3. Roof covering = squares × base price × metro multiplier × HVHZ multiplier × pitch multiplier × story multiplier, for the low, typical and high bands separately.
4. Adders, each as its own line:
   • Extra tear-off layer: $50–$150 per square (estimate).
   • Tile tear-off premium when the old roof is tile and the new one isn't: $75–$150 per square (estimate).
   • Deck re-nailing (FBC-EB 706.7.1) for homes built before 2002: $20–$60 per square (estimate; no published figure exists).
   • Deck sheet allowance: 10% of 4×8 sheets for homes built before 2002, 3% otherwise, at $70–$130 per sheet installed (estimate). Sheets = roof area ÷ 32 sq ft.
   • Roof-to-wall retrofit (FBC-EB 706.8) when the home was permitted before 1987 and is worth $300,000 or more: 5% (low), 10% (typical) and 15% (high) of the roof covering line. The bands are our estimate; 15% is the code's cap on required spending.
   • Permit and inspection fees: $250 / $400 / $1,000 per job, anchored on the Miami-Dade median permit fee of $312. Fees vary by jurisdiction and are changing under HB 803; confirm with your building department.
5. Rounding. Lines are rounded to $50 and totals to $100.

Confidence. Architectural shingle prices rest on the most permit data and carry high confidence. Concrete tile, standing-seam metal and flat roofs are medium; 5V-crimp metal is low to medium; clay tile and 3-tab shingle are low. Results are estimates, not quotes. A contractor's measurement and written estimate are what count.

Parcel and building-footprint lookup

The address search in the cost calculator and roof age check matches your address to a parcel record and a building footprint.

• Parcels: Florida Department of Revenue 2026 tax-roll (NAL) files and county parcel shapes, filtered to single-family homes (DOR use code 001). We keep parcel ID, county, normalized address, ZIP, actual and effective year built, and use code.
• Footprints: Microsoft US Building Footprints for Florida (7.26 million buildings), licensed under the Open Database License (ODbL). We take the largest footprint inside each parcel. Lookups are produced works under the ODbL; we don't publish the derived database.
• Coverage: Manatee and Charlotte counties for now. Elsewhere you enter the area yourself.
• Accuracy caveats: a footprint is the building's outline seen from above. It can include a covered patio, miss a detached structure or merge attached buildings, and the overhang allowance is an average. Pitch is your choice, not measured. The year built in tax records is the year the home was built, not the roof.
• Privacy: the address is sent by POST, so it never appears in a URL, and it is not stored or logged. See the privacy notice.

Permit datasets

Attribution: Building footprints © Microsoft (ODbL). Permit data: Manatee County Government; Charlotte County GIS. Parcel data: Florida Department of Revenue.

Roof age and insurance check

The roof age check takes the install year (from a permit, your entry, or the year the home was built), the material and your insurer type, and applies these rules in order:

1. Past typical service life if the roof is older than the top of the typical Florida range for its material.
2. Time to plan if it has reached 75% of the planning life for its material, or if you're insured with Citizens and the roof is over 25 years (shingle, flat) or 50 years (tile, metal).
3. Under 15 years if the roof is under 15 years old (§627.7011(5)).
4. Otherwise, inspection window: 15 years or older but under 75% of typical life.

It also flags the Citizens 4-point inspection for homes more than 20 years old, and the 25% rule: a permit dated March 2009 or later, or an install year of 2010 or later, is treated as likely exempt under §553.844(5); an install year of 2009 means "check the permit date"; earlier years mean the rule applies. The 75% mark is our planning rule of thumb, not a legal threshold.

Repair-or-replace checker

The repair-or-replace checker uses the same lifespans. Only the first rule is a legal threshold; the rest are rules of thumb.

1. Code trigger: the roof predates the 2007 code (you said it wasn't permitted on or after March 1, 2009, or you don't know and it was installed before 2010) and 25% or more is affected.
2. Replacement likely: the roof is at 75% or more of planning life with two or more whole-roof symptoms; or past 100% with at least one; or your insurer has flagged it; or more than half the roof is affected.
3. Repair likely: under 60% of planning life, no whole-roof symptoms, and under 25% affected.
4. Otherwise borderline, with a note when you plan to stay 10+ years and the roof is past half its life.

Whole-roof symptoms are heavy granule loss, curling, visible or brittle tile underlayment, rusted or loose metal fasteners, ponding on flat roofs, leaks in more than one place, and a soft deck. Isolated cracked tiles and storm-lifted pieces count as local.

Legal sources

We re-check these when any of the following happens: the 9th edition Florida Building Code takes effect (December 31, 2026; we'll re-check the 25% rule section numbers); the 2027 legislative session ends; Citizens issues a new roof bulletin; the OIR-B1-1802 form or its rule changes; or local permit fee schedules change under HB 803.

Sources we exclude

We don't use these at all, because they were AI-generated microsites, spam on hijacked domains, sponsored content, or had broken numbers (such as $0 labor):

• *.lovable.app (Roof360/roofpack)
• new.risingsunartscentre.org
• partner.kurlon.com / selector.kurlon.com
• contractorplus.app ($0 labor)
• storyconsole.* sponsored content

We read but don't rely on contractor marketing and programmatic cost pages with no stated method: foxhavenroof.com, roofvista.com, resident.com, roofobservations.com, inchcalculator.com, jobnimbus.com.

Figures we could see only in a search snippet are labeled "unverified" wherever we use them.

Update schedule

• Permit data: the Manatee County data are refreshed from the county service; Charlotte's 2000–2016 layer is static.
• Cost model: re-based when new permit data or price indexes move materially. Estimates dated 2027 or later should allow for material escalation of about 4% a year for shingle and tile and 6% for metal (our estimate from producer price trends).
• Legal facts: on the triggers above, and the "Last reviewed" date on each page shows when we last checked.

See also our editorial policy.