Florida Certified Roofing Contractor CCC 1334537
Why is my metal roof rusting so fast near the coast?
A straight answer from a Florida certified roofing contractor — then what you can check yourself and when to call. Free quote: (954) 775-8990.
Salt air is the main cause. Salt carried on coastal wind settles on the roof as chloride and eats through any spot where the protective coating is thin, scratched or cut. The fasteners, cut panel edges, flashings and drip edge usually go first.
The metal and coating matter as much as the location. Bare or lightly coated steel, or fasteners that don't suit the panel metal, will rust far sooner than aluminum or galvalume with a finish made for coastal exposure. Surface rust at a few screw heads is a maintenance item. Rust that is flaking, streaking or opening holes in the metal means the coating has failed and the system needs attention.
Why it happens
Metal roofs rely on a thin protective layer, such as a galvalume or paint finish. Salt-laden air attacks that layer wherever it is weakest. Cut edges, drilled fastener holes, scratches from installation and bends formed on site all expose raw metal. Florida's year-round humidity keeps those spots damp, which speeds corrosion.
Fasteners are a common weak point. A screw or nail not rated for salt air can rust, swell and stain the panel below it. Some metals in contact with each other can also corrode one another when moisture is present. In exposed-fastener systems, heat expansion and contraction can slowly back screws out and loosen the seal. That lets water and salt sit around the hole, so rust starts there.
Rain normally rinses salt off, but sheltered areas such as under eaves, behind ridge caps and along walls can hold it. Leaves and debris packed into valleys or gutters stay wet and add to the problem. This is why one section of a roof can rust much faster than the rest.
What you can check yourself
Look from the ground
Stand back, or use binoculars, and look for rust streaks running down from screws, ridge lines, valleys and the drip edge. Keep your feet on the ground and don't climb onto the roof.
Check the gutters and fascia
Orange or brown staining on gutters, fascia or the wall below the roofline points to runoff from corroding metal above. Debris sitting in gutters is worth noting too.
Look in the attic
With a flashlight, inspect the underside of the roof deck near fasteners and penetrations for rust specks, water stains or damp insulation. Any of these suggest moisture is getting through.
Scan the ceilings
Brown rings or bubbling paint on upstairs ceilings, especially below roof vents, chimneys or valleys, can mean a leak has already started.
When to call a pro
Call when rust is flaking, when screw heads are eaten away, when panels or flashings show holes, or when you see staining inside the house. Rust at fasteners and flashings is hard to judge from the ground, and a coating that has failed usually can't be fixed by painting over it. We'll inspect it, tell you what is salvageable and put the scope in a written flat rate quote that says what is included. The estimate is free.
On licensing and permits, the rule is: "Roofing work in Florida legally requires a licensed roofing contractor and generally a permit from the local building department; a contractor's license is verified on the Florida DBPR website." Our Florida Certified Roofing Contractor license is CCC1334537, and we pull permits under our own license. Call (954) 775-8990, where the phone is answered around the clock, or use the estimate form.
What a pro will do
- Inspect fasteners, flashings and edgesWe check where corrosion starts: screws, cut edges, penetrations, wall terminations and the drip edge. We also look for rotten deck or fascia underneath.
- Choose a coastal-appropriate metal and finishIf panels need replacing, aluminum or galvalume finished for coastal exposure, with compatible fasteners, resists salt air better than unprotected metal.
- Replace failed flashing and repair the deckFlashing at skylights, vents and walls is rebuilt, and rotten plywood and fascia replacement is included in our scope. We reset or replace loose and corroded fasteners.
- Install to code, with permit and inspectionsPanel attachment, uplift and underlayment follow the Florida Building Code. We schedule and pass the inspections, close out the permit and clean up.
Related questions
- Can I just paint over the rust?
- On light surface rust, cleaning and recoating can sometimes help, but it depends on how far the corrosion has gone. If the metal is pitted, flaking or perforated, or fasteners are failing, paint only hides the problem. An inspection will tell you which situation you have.
- Does a new metal roof need product approval?
- Yes. The rule is: "Miami-Dade and Broward are Florida's High-Velocity Hurricane Zone. Roofing products used there need a Miami-Dade Notice of Acceptance (NOA) for that use; elsewhere in Florida they need a Florida Product Approval (or local approval). Either way the product is installed per its approval."
- What decides the cost of fixing or replacing a rusting metal roof?
- The main factors are roof size and access, the panel type and finish, the permit, and what we find once the roof is opened up, such as damaged deck or fascia. Because of that last factor we inspect first and give you a free written flat rate quote that says what is included.
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