Broward County HVHZ | Roof Systems

First Line of Defense: Roof Edge Metal

Your roof edge is where hurricanes attack first. Wind speeds up as it rolls over the edge, creating massive uplift. If the edge fails, everything else follows. Here is how to stop it.

0 mph
Edge Wind Speed
4" O.C.
Fastener Spacing
2x
Higher Edge Pressure
Roof Edge Wind Attack Simulation
Drip Edge Fascia Membrane
Edge Uplift Pressure
-48 PSF

Know Your Roof Edge Components

Each piece has a job. When one fails, they all fail. Here is what each does and why it matters.

Drip Edge

An L-shaped metal strip that goes under the shingles at the edge. It guides water into the gutter and keeps it from running down the fascia.

Material Galvanized Steel
HVHZ Fastening 4" on center
Min. Leg Height 2 inches

Fascia Board

The vertical board at the roof edge that covers the rafter tails. It is what your gutters attach to. Also stops wind from getting into the attic.

Material Wood or Composite
HVHZ Fastening Ring-shank nails
Typical Width 1x6 or 1x8

Gravel Stop

Used on flat roofs. A taller edge piece that keeps gravel or ballast from blowing off and stops water from running down the wall face.

Material Aluminum or Steel
HVHZ Fastening 4" on center
Min. Height 4 inches

Edge Fastener Spacing Calculator

Find out how close your fasteners need to be based on your roof edge location.

Recommended Fastener Spacing
4"
on center

How Roof Edges Fail in Hurricanes

It happens fast. One failure leads to the next. Understanding this helps you prevent it.

1

Wind Undercuts the Edge

Wind hits the wall and rolls up. As it goes over the roof edge, it speeds up and creates strong suction. This pulls up on the edge metal from below.

2

Fasteners Pull Out or Break

If fasteners are too far apart or too short, the uplift force pulls them out. One fastener fails, then the next one takes more load and fails too.

3

Edge Metal Peels Back

Once the edge starts to lift, wind gets underneath. Now it is pushing up instead of just sucking. The metal peels back like opening a sardine can.

4

Membrane and Sheathing Follow

With the edge gone, wind attacks the roof membrane and sheathing directly. These peel off in sheets. Now water can pour in.

Roof Edge Metal FAQs

Why do roof edges fail first in hurricanes?
Wind speeds up as it flows over a roof edge, creating strong uplift. This lifting force is highest at corners and edges. If the edge metal is not properly fastened, wind gets underneath and peels it back like opening a can. The edge sees about twice the pressure that the middle of the roof sees.
What is the difference between drip edge and gravel stop?
Drip edge is an L-shaped metal that goes on sloped roofs to direct water into gutters. Gravel stop is a taller edge piece used on flat roofs to keep gravel in place and stop water from running down the wall. Both need to be fastened at 4 inches on center in HVHZ areas.
How often should roof edge metal be fastened in Broward County?
In the HVHZ, roof edge metal typically needs fasteners every 4 inches on center at edges and corners. This is much closer than the 12-inch spacing allowed in non-hurricane zones. Use ring-shank nails or screws rated for the wind pressure at your location.
What happens when fascia fails during a hurricane?
When fascia fails, it exposes the roof structure to wind and water. Wind can then get under the roof sheathing and peel it off. Water enters the attic and damages insulation, ceilings, and anything stored there. It also means your gutters are gone, so water pours down your walls.
Broward Edge Stats
Wind Speed 180 mph
Edge Zone Pressure -85 PSF
Corner Pressure -110 PSF
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