Expert advice on how to clean and repair metal roofing, including fixing leaks, replacing loose fasteners, repairing rust damage, and patching damaged metal roof panels.
Quick Answer
How to Clean a Metal Roof
Repairing Loose Roofing Fasteners
How to Repair Rust & Corrosion
How to Repair Metal Roof Leaks
Preventive Maintenance
When to Call a Professional
FAQs
Metal roofs are among the most durable roofing materials available, but even metal roofing occasionally needs maintenance or repair. Over time, fasteners can loosen, flashing can fail, sealants can deteriorate, and exposed metal may begin to rust or corrode.
Fortunately, many smaller metal roof problems can be handled before they turn into expensive leaks or structural damage.
The most common metal roof repairs include:
- Replacing loose or missing fasteners
- Repairing rust or corrosion
- Fixing roof leaks around seams or flashing
- Patching damaged metal panels
- Replacing failed sealants
Standing-seam roofs and steep roofs often require specialized tools and safety equipment, so some repairs are best left to experienced metal roofing contractors.
Metal roofs can be extremely slippery—especially when wet, dusty, or coated with algae. Use proper fall protection and avoid walking on steep or wet metal roofing.
Quick Answer
Most metal roof repairs involve fixing loose fasteners, repairing flashing or seams, treating rust, or patching damaged panels. Small problems should be repaired promptly because water intrusion around fasteners or seams can eventually damage roof decking and framing beneath the roofing.
Don’s Advice
One of the smartest things homeowners can do with a metal roof is address small problems early.
A slightly loose fastener or tiny failed seal can often be repaired easily and inexpensively. But once water starts getting beneath the roofing, repairs become far more complicated and expensive.
How to Clean a Metal Roof
Before repairing a metal roof—or even inspecting it closely—it helps to clean dirt, debris, mildew, and oxidation from the surface.
A clean roof makes it easier to spot:
- Loose fasteners
- Failed sealant
- Rust spots
- Damaged flashing
- Cracks or punctures
Use the Right Cleaner
For most roofs, a mild detergent mixed with water works well.
You can also use:
- Metal roof cleaners
- Mildew removers approved for metal roofing
- Oxidation removers for painted metal roofs
A typical cleaning mixture is about:
- 1 part mild detergent
- 4 parts water
Always follow manufacturer recommendations for specialty cleaners.
Apply the Cleaning Solution
Use:
- A soft-bristle brush
- A low-pressure sprayer
- A garden sprayer
Allow the cleaner to sit briefly so it can loosen dirt and stains before rinsing thoroughly.
Using a Pressure Washer Safely
A pressure washer can clean a metal roof effectively, but excessive pressure can damage coatings, force water beneath panels, or dent softer metals.
In most cases:
- 1000–1200 PSI is sufficient
- Use a wide-angle nozzle
- Hold the nozzle 18–24 inches from the surface
- Spray downward—not upward beneath seams
Softer metals such as copper or aluminum may require lower pressure settings.
Don’s Advice
One of the easiest ways to accidentally damage a metal roof is spraying upward beneath seams or laps with a pressure washer.
That can force water beneath the roofing and sometimes even beneath underlayment.
Rinse Thoroughly
After cleaning, rinse the roof completely to remove detergent residue that could eventually damage coatings or finishes.
Pay particular attention to:
- Valleys
- Seams
- Fastener rows
- Areas around flashing
Repairing Loose Roofing Fasteners
One of the most common metal roof problems involves fasteners that loosen over time due to expansion and contraction of the metal panels.
Loose fasteners can allow:
- Leaks
- Panel movement
- Wind noise
- Panel uplift during storms
Inspect the Roof Carefully
Pay close attention to:
- Roof edges
- Ridges
- Valleys
- Areas exposed to high wind
- Panels near flashing
Look for:
- Missing screws
- Raised fasteners
- Cracked rubber washers
- Corroded fasteners
- Enlarged holes
Tighten Loose Fasteners
Use a drill or driver carefully.
Avoid overtightening, which can:
- Crush washers
- Strip holes
- Distort panels
- Create future leaks
Replace Damaged Fasteners
Use replacement fasteners that:
- Match the original size and type
- Include neoprene sealing washers
- Are approved for metal roofing
If holes have enlarged, oversized repair fasteners may be needed.
Seal Problem Areas
Roof sealant may help reinforce vulnerable fastener locations, especially on older roofs.
See also: How to Find & Repair Roof Leaks
How to Repair Metal Roof Rust & Corrosion
Although many modern metal roofs are coated to resist corrosion, rust can still develop if coatings become scratched, worn, or damaged.
Rust commonly appears:
- Near exposed fasteners
- Around scratches
- At cut panel edges
- Where debris traps moisture
- On older galvanized roofing
Remove Rust
Use:
- A wire brush
- Steel wool
- Medium-grit sandpaper
Remove all loose rust before applying coatings.
Clean the Area
Wipe away dust and debris thoroughly.
The surface should be dry and clean before priming.
Apply Rust Inhibitor & Primer
Spray-on rust inhibitors help stop corrosion from spreading.
Then apply:
- A metal roof primer
- A rust-inhibiting metal primer
Follow product instructions carefully.
Apply a Finish Coat
After priming, apply:
- Metal roof coating
- Metal roof paint
- Touch-up paint matching the roof color
See also:
Best Primers for Metal Roof Paints
How to Choose Metal Roof Paint
Repairing Metal Roof Leaks
Metal roof leaks often develop around:
- Fasteners
- Flashing
- Roof penetrations
- Panel seams
- Skylights
- Chimneys
Standing water, failed sealants, and roof movement can all contribute to leaks.
Find the Source Carefully
Water often travels before becoming visible indoors, so the leak source may not be directly above the ceiling stain.
Inspect:
- Seams
- Flashing joints
- Pipe boots
- Ridge caps
- Fastener rows
For more guidance, see How to Find & Fix Roof Leaks.
Patching Small Damaged Areas
For small punctures or localized panel damage:
- Cut out damaged material if necessary.
- Cut a matching patch from compatible metal roofing.
- Apply urethane roofing cement beneath the patch.
- Fasten the patch securely using metal roofing screws.
- Seal all edges and fasteners carefully.
- Touch up with matching roof paint.
Because metal roof leaks can involve complicated flashing details, major repairs are often best handled by specialists experienced with metal roofing systems.
Preventive Maintenance for Metal Roofs
Routine inspections and maintenance can greatly extend the life of a metal roof.
At least once or twice a year:
- Remove leaves and debris
- Inspect flashing
- Check fasteners
- Look for scratches or rust
- Inspect sealants
- Check valleys and gutters
- Inspect after severe storms
Tree branches that scrape the roof repeatedly can eventually damage coatings and paint finishes.
Need Professional Help?
Steep roofs, standing-seam roofing, storm damage, and major leak repairs are often safest and most effectively handled by experienced metal roofing contractors.
Find a trusted local roofing contractor for inspections and repairs.
When to Call a Professional
Call a roofing professional if:
- The roof is steep or difficult to access
- Leaks involve flashing or seams
- Panels are badly damaged
- Storm damage is extensive
- Standing-seam roofing requires repair
- You suspect structural damage beneath the roofing
Metal roofing specialists have specialized tools and experience that many general roofers do not.
FAQs
Can you pressure wash a metal roof?
Yes, but use moderate pressure and avoid spraying upward beneath seams or flashing.
What causes metal roof leaks?
Common causes include loose fasteners, failed flashing, deteriorated sealant, rust, and damaged panels.
How do you stop rust on a metal roof?
Remove loose rust, apply rust inhibitor and primer, and then coat the area with appropriate metal roof paint or coating.
Can loose fasteners cause leaks?
Yes. Loose or deteriorated fasteners are one of the most common causes of metal roof leaks.
How long do metal roofs last?
Many properly maintained metal roofs last 40 to 70 years or longer depending on the material and installation quality.
