Florida Roofing Glossary: Terms Explained
Plain-English definitions of the roofing, code and insurance terms Treasure Coast homeowners run into, from "square" and "underlayment" to "secondary water barrier," "25% rule" and "4-point inspection." If a roofer, adjuster or inspector uses a word you do not know, it is probably here. Maintained by Leeward Roofing (CCC1337211), Sebastian, FL.
Roofing terms, in plain language
Grouped the way you will hear them: the roof itself, Florida code, and insurance.
Square
Roofing unit equal to 100 square feet of roof surface. A 2,000 sq ft roof is 20 squares.
Tear-off
Removing the existing roof down to the deck before installing a new one. Most Treasure Coast re-roofs are full tear-offs.
Decking (sheathing)
The plywood or OSB boards the roof is built on. Rotted decking is replaced after tear-off.
Underlayment
The water-resistant layer between the deck and the finished roof.
Secondary water barrier (SWB)
A sealed underlayment layer that keeps water out if the finished roof is blown off. It can earn a wind mitigation credit.
Drip edge
Metal edge flashing at the eaves and rakes that directs water into the gutter and protects the deck edge.
Flashing
Metal pieces that seal joints at walls, chimneys, skylights, valleys and vents. The most common leak source.
Valley
Where two roof slopes meet in an inside corner. Carries a lot of water and needs careful flashing.
Ridge vent
A vent along the peak that lets hot attic air escape. Part of attic ventilation.
Soffit and fascia
Soffit is the underside of the roof overhang; fascia is the board along the roof edge. See soffit and fascia damage.
Hip roof vs. gable roof
A hip roof slopes down on all four sides; a gable roof has flat triangular end walls. Hip roofs generally perform better in wind and can earn a wind mitigation credit.
Florida code terms
The words that show up on permits and product approvals.
Roof-to-wall connection
How the roof framing is tied to the walls: toe nails, clips, single wraps or double wraps. Stronger connections earn bigger wind mitigation credits.
Cap nails
Nails with a wide plastic or metal cap used to fasten underlayment. Metal cap nails are required where design wind speed is 150 mph or higher, which covers the Treasure Coast.
Design wind speed
The wind speed a roof must be engineered for. About 150 mph west of I-95 and 160 mph east of it in Indian River and St. Lucie County.
Exposure category (B, C, D)
How open the land upwind of a building is. Exposure D, near open water, requires the strongest wind design; much of the barrier island is Exposure D.
Florida Product Approval
State approval showing a roofing product is tested and approved for Florida wind zones. Required on the permit.
Miami-Dade NOA
Notice of Acceptance from Miami-Dade County, the strictest product approval in the state. Required in the High-Velocity Hurricane Zone and often cited elsewhere.
HVHZ
High-Velocity Hurricane Zone: Miami-Dade and Broward County only, with stricter rules than the rest of Florida. The Treasure Coast is not in the HVHZ.
25% rule
If more than 25% of a roof section is repaired or replaced within 12 months, it generally must be brought to current code, unless the roof was built to the 2007 code or later. See the 25% rule.
Insurance and material terms
What adjusters, inspectors and estimates mean.
Wind mitigation inspection
An inspection on the state form that documents wind-resistant features so insurers can apply premium credits. See wind mitigation.
4-point inspection
An insurance inspection of roof, electrical, plumbing and HVAC, commonly required on older homes. See selling with an old roof.
Architectural shingle
A thicker, dimensional asphalt shingle, the standard shingle on Florida re-roofs today.
Standing seam metal
Metal panels joined by raised vertical seams with concealed fasteners. Lasts 40 to 70 years. See standing seam.
5V crimp
Exposed-fastener metal panel with five V-shaped ribs, a classic Florida metal roof.
Tile lift-and-relay
Removing existing concrete or clay tile, replacing the underlayment, and reinstalling the same tile.
TPO
Thermoplastic polyolefin, a single-ply membrane used on flat and low-slope roofs. See TPO roofing.
Low-slope roof
A roof with little pitch, roughly under 3:12, that needs membrane systems instead of shingles.
Pitch
Roof steepness, written as rise over 12 inches of run, for example 6:12.
Roof permit
Required for a Florida roof replacement. Includes a roof diagram and product approvals. See Indian River County permits.
Wind got under it? Do not wait for the next band.
Lifted shingles and displaced tile rarely reseal themselves. The cheapest version of this job is the one that happens before the next system comes through.
- Walk the perimeter and look for granules washed into the gutters and downspouts.
- Photograph soffit, fascia and gutter damage — adjusters ask for it.
- Tarp first, then worry about the permanent repair.
- Be wary of out-of-state crews that appear the day after a storm.
Recent Leeward jobs
Real Treasure Coast roofs installed by our own crews — not stock photography.
Glossary FAQs
What is a square in roofing?
A roofing square is 100 square feet of roof surface. Roofers price and order materials by the square.
What is a secondary water barrier on a roof?
A sealed underlayment layer that keeps water out of the house if the finished roof covering is blown off. In Florida it can earn a wind mitigation insurance credit.
What is the HVHZ in Florida?
The High-Velocity Hurricane Zone, which covers only Miami-Dade and Broward County and has stricter building rules. The Treasure Coast is not in the HVHZ.
What is a roof-to-wall connection?
The hardware tying roof framing to the walls, rated on the wind mitigation form as toe nails, clips, single wraps or double wraps. Stronger connections earn larger insurance credits.
What is the difference between a hip and a gable roof?
A hip roof slopes down on all four sides; a gable roof has triangular end walls. Hip roofs generally handle wind better and can earn a wind mitigation credit in Florida.
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