How to Repair a Hole in a Metal Roof System

A metal roof system can develop holes over time due to a variety of factors like hail damage, fallen tree limbs, foot traffic, or age and corrosion. Repairing these holes quickly is important to prevent further damage from water leaks. With the right materials and proper technique, you can repair metal roof holes yourself and restore the integrity of your roof.

Safety Precautions When Working on a Metal Roof

Working on a roof can be dangerous, so take proper safety precautions:

Use a harness, ropes, and roof jacks securely attached to the roof framing to prevent falls.
Wear shoes with grippy soles to avoid slipping.
Don’t work on wet, icy, or excessively windy days.
Use extreme caution when working near gutter edges or skylights.
Have someone monitor you from the ground.
Cordon off the area below your workspace.
Use padding when kneeling.
Take regular breaks to avoid fatigue.
Keep tools secured so they don’t slide off the roof.
Wear protective goggles, gloves, and long sleeves, as metal edges are sharp.

How to Inspect and Identify Holes in a Metal Roof

Thoroughly inspect all surfaces of the metal roof from both the ground level and up close to locate holes and identify what caused them:

Scan for rust stains, water damage, or daylight shining through, as these often surround holes.
Look along seams, joints, screws or fastener points as potential weak spots.
Inspect areas under air conditioning units or other mounted equipment that could corrode from condensation runoff.
Check for gaps where the roof meets walls, chimneys, skylights, or vents.
Review locations where tree branches make contact or where falling debris is likely.
Examine areas where people frequently walk.

Determining the cause will help assess the proper repair. Rust or deterioration indicates a patch, while hail or accidental damage may only require sealing the puncture. Measure the hole size too.

How to Clean and Prepare the Metal Roof Surface

Proper cleaning and preparation ensures repairs adhere correctly:

Sweep away any dirt, leaves, or debris surrounding the hole.
Scrub surrounding areas with a wire brush to remove rust flakes or scale.
Clean surfaces using metal prep solvents and rinse thoroughly.
Dry the area completely with rags before applying any sealant or coating.
Abrade metal surfaces with 80 grit sandpaper to improve adhesion.
Use a utility knife to feather and smooth any jagged metal edges.
Apply alcohol or acetone with a rag to eliminate oily residues prior to repair.

A clean bare metal surface allows the best bonding with repair compounds. Avoid any greasy residue interfering with adhesion.

How to Patch Small Holes in a Metal Roof

For punctures less than 1 inch across:

Apply a drop of metal epoxy over the puncture, spreading it slightly beyond the edges.
Cover with an aluminum or galvanized patch 2-4 inches square centered over the hole while the epoxy is still wet.
Press firmly to adhere and spread the epoxy onto the metal patch forming a strong bond.
Clamp the patch in place with pliers and allow the epoxy to fully cure per manufacturer instructions.

Larger patches provide more adhesion surface area and durability. Aluminum patches work for both aluminum and galvanized steel roofs. Always follow the epoxy instructions precisely.

How to Seal Screw and Fastener Points

Exposed seams or fastener points allow moisture intrusion:

Clear dirt and caulk debris from seams with a putty knife. Do not damage roof material.
Dry all screw or fastener points thoroughly before sealing.
Apply exterior grade polyurethane sealant over and around fasteners and seams.
Work sealant into gaps with a putty knife or screwdriver pressed firmly to displace air pockets.
Smooth excess sealant with a putty knife angled to form a 45 degree fillet.
Continue smoothing until the sealant firmly adheres without air pockets.

Inspect all screw points, even if not leaking currently. Resealing helps prevent future problems.

How to Patch Larger Holes in a Metal Roof

For holes larger than 1 inch:

Mark the hole shape onto cardboard and cut out a template.
Trace the template onto a metal flashing or sheet matching the roof metal type.
Cut the patch allowing 2-3 inches excess beyond the hole edges.
Scrub patch and roof surfaces with a wire brush and apply metal prep solvent.
Apply a thick bead of roofing sealant around hole edges.
Position the patch over the hole centered smoothly without stretching or overlap.
Drill pilot holes and fasten the patch every 4-6 inches with plated screws into roof rafters or beams.
Apply generous sealant over all screw heads and edges for a watertight seal.

The patch must span at least 2 inches past damaged areas for proper strength. Take care not to drill through interior ceilings below.

How to Repair Rusted Areas on Metal Roofs

For rusted roof sections:

Use an angle grinder to remove loose roof coating and fully expose rusted metal. Wear eye protection!
Sand damaged areas thoroughly to clean bare metal. Feather edges to taper smoothly.
Apply an appropriate rust-inhibiting primer and allow drying completely.
Spread roof sealant to completely fill any pitted areas, smoothing the surface.
Once sealant has cured, apply a top coating of elastomeric roof paint.
Extend repair finish coatings at least 6 inches beyond repaired area.

Severe rust may require replacing entire roof sheets. Normal rusting can often be arrested and coatings renewed to extend roof life.

How to Repair Open Roof Seams and Joints

Separated roof panel seams must be resealed:

Pry open the standing seam with a flat bar and thoroughly clean inside surfaces with a wire brush.
Wipe down both sides of the seam with metal prep solvent and let dry completely.
Apply a generous bead of roof sealant along both sides of the seam.
Firmly push the seam closed tightly with pliers or clamps. Add clamps if needed.
Smooth excess sealant over the resealed seam with a putty knife. Press in firmly without gaps.
Remove clamps after sealant partly cures. Then apply a second coat focused just along seam edges.

Proper cleaning and clamping pressure are vital for creating leak-free sealed seams. Avoid thinning sealants, only apply as directed.

How to Seal Roof Leaks Around Chimneys

Chimney roof protrusions often leak and must be resealed:

Inspect the chimney flashing for open seams, cracks, or gaps from the roof surface.
Clean and sand areas needing repair to expose fresh bare metal.
Apply primer to bare metal, then apply roofing sealant in needed areas.
For sagging flashing, push back up with a pry bar while applying additional sealant on top.
Caulk the junction between chimney and roof surface fully around perimeter.
Smooth any protruding sealant beads with a putty knife or wet finger for a flat uniform seal.
Apply elastomeric coating over sealed areas and extend at least 6 inches beyond repair.

Careful inspection and fully sealing all possible leak points will protect this vulnerable roof joint.

How to Repair Gutters and Downspouts

Check all roof gutters and downspouts for:

Leaks at seams – clean and seal with gutter sealant.
Sagging areas – use hangers to re-support.
Disconnected sections – reposition and seal.
Downspout leaks – seal with caulk or tape.
Missing or damaged hangers – replace hangers.
Clogs from debris – clear out buildup.
Proper slope to drain water – adjust hangers.
Secure downspout attachments – refasten joints.

Proper gutter slope and drainage prevents overflows that could leak into a home. Keep gutters cleaned and aligned.

How to Seal Roof Leaks Around Vent Pipes

Roof protrusions like vents commonly leak. To stop leaks:

Detach any shroud or rain cap to access the roof flashing seal.
Clean and sand the flashing base where it contacts the roof.
Apply primer then a generous sealant bead under the flashing base.
Smooth sealant with a putty knife and reseat flashing firmly.
Apply additional sealant over the flashing edges and any exposed fasteners.
Replace the vent shroud. Caulk shroud edges and any vertical seams.
Coat sealed areas with elastomeric sealant extending 6 inches past repairs.

Proper sealant application techniques ensure water flows over rather than under flashing.

How to Repair Leaks Where Roof Meets a Vertical Wall

Leaks often occur where roof sections meet walls. To repair:

Inspect the step flashing or wall flashing for gaps at the roof junction.
Clean and sand areas that require resealing.
Apply primer then roof sealant in needed areas under flashings.
Reseat any sections that have lifted. Apply additional sealant atop seams.
Caulk the junction seam where roof and wall meet all around.
Apply an elastomeric coating extending 6 inches up the wall and out onto the roof surface.
Fill any cracks or holes in the wall or roof materials near the junction.

Take extra care sealing roof-wall joints since moisture buildup here can easily enter the attic or structure.

How to Replace Damaged Sections of Metal Roofing

For badly corroded roof panels:

Mark or measure the damaged section to be replaced. Include 2-3 inches overlap past damages.
Using tin snips, cut through fasteners to remove the damaged section.
Cut a replacement panel to match dimensions of removed section.
Coat panel overlap edges with roof primer and sealant. Secure with new fasteners.
Apply flexible sealant between new panel ribs and over all fastener heads.
Caulk and coat junctions, providing at least 6 inches overlap onto existing roof.

Avoid walking on adjacent panels which could damage the surface. Remove only fasteners necessary to access repairs.

How to Cover Exposed Nail Heads on a Metal Roof

Exposed fastener heads provide a path for water to penetrate the roof. Each one must be sealed:

Locate and identify all fastener heads needing sealing. They may be rusty or have drips underneath.
Clean fastener head and surrounding area with wire brush to remove rust and debris.
Apply roofing sealant over fastener head and smooth into a flat bead with a putty knife.
For large roof areas, consider a maintenance coating over all exposed fasteners.

Spot treating troublesome fasteners as needed is recommended. But eventually, a roof coating renewal may be required.

How to Patch or Seal Holes from Hail Damage

Hail-damaged metal roof areas require patching:

Identify all hail strike points and mark ones that pierced the metal.
Clean piercings then apply sealant into each to seal. Add a metal patch if needed.
For dents, gently hammer from beneath to flatten without creasing if possible.
Fill deeper dents with sealant and smooth flat with a putty knife or trowel.
When repairs are complete, apply protective elastomeric coating over repaired areas.

Quickly sealing punctures helps prevent interior damage. Contact your insurance company regarding hail damage claims and re-inspection.

How to Repair Damage from Wind or Falling Debris

Storm damage requires immediate repair:

Carefully inspect for punctures or tears from wind-blown debris. Also check for intact flashings.
Seal punctures from tree limbs, branches, etc. with metal epoxy patches applied properly.
Temporarily cover any major holes or openings to prevent water intrusion.
Replace any sections of metal roofing that were punctured or torn off completely.
Check that all roof flashings remain sealed down securely with no lifting. Reseal as needed.
Apply a protective roof coating after repairs have been completed.

Promptly fixing storm damage prevents secondary water leakage damage. Document all repairs for insurance claims.

How to Repair Rust Damage from Standing Water

Prevent roof rusting by ensuring proper drainage:

Identify areas where water collects and sits for prolonged periods.
Check downspouts and gutters for proper slope drainage and remove any debris clogging.
Seal over fastener points or seams in problem areas using roofing sealant.
Fill depressions with roof sealant to create positive slope and drainage.
Rework or add drip edges so runoff drains fully off roof edges.
Coat repaired areas and rust spots with elastomeric sealant when dry.

Eliminating puddling water prevents ongoing rust formation and damage. Maintain drainage systems regularly.

How to Maintain Walkways on a Metal Roof

Regular walkways require repair and water sealing:

Sweep away dirt and debris to access walkway surface. Scrub with degreaser and rinse.
Allow to dry fully, then sand walkway panels lightly to abrade surface for coating adhesion.
Apply elastomeric roof coating per product instructions for bridging foot traffic areas.
Avoid traffic over walkways until coating has time to fully cure to avoid scuffing.

Minor surface rusting of walkways can often be cleaned and resealed to extend useful life. Avoid unnecessary foot traffic.

How to Apply Roof Sealants and Coatings

Correct procedures ensure good results:

Only apply sealants or coatings in dry weather with no rain forecast for 24 hours.
Roof surfaces must be clean and dry before application.
Mix and thin coatings per manufacturer instructions. Do not over-thin.
Fill voids and spaces fully before applying a final sealing top coat.
Smooth top coats with uniform thickness across repair zones.
Extend elastomeric coatings at least 6 inches beyond repair areas.

Applying sealants and coatings on damp or dirty surfaces prevents proper adhesion and curing. Follow directions!

Tips for Preventing Future Metal Roof Damage

Good maintenance prevents premature repairs:

Inspect metal roofs twice per year and reseal fasteners, seams, and flashing.
Avoid unnecessary foot traffic and clean gutters without walking on roof panels.
Keep trees and overhanging branches trimmed back from contact with the roof.
Service roof-mounted AC units regularly to prevent condensate corrosion.
Clear off accumulated debris like leaves frequently to encourage drainage.
Recoat exposed fastener heads every 5-7 years as preventative maintenance.

Proactive maintenance makes metal roof repairs less frequent and extends roof lifetime.

Signs It’s Time to Replace Your Metal Roof

While metal roofs are durable, there comes a point when repairs are no longer cost-effective. Consider full replacement when:

Leaks arise in many sections of roofing material, not just seams or flashing.
Roof coatings can no longer adhere due to excessive rust scaling.
Walkways are very corroded with holes or unsafe, weakened panels.
Repair costs annually exceed 20% of a new metal roof installation.
Roof coating colors have faded indicating UV breakdown of polymers.
You need environmental control for mold or asbestos contained in roof materials.

Compare costs of continued repairs versus new roof installation. Evaluating overall condition helps determine if total replacement is the best option.

Key Takeaways on Repairing Metal Roofs

Identify all holes, rust areas, and needed repairs during thorough roof inspection.
Always use proper safety precautions when doing roof work.
Clean and abrade surfaces fully before applying any sealants or coatings.
Seal all fastener points, seams, penetrations, flashings, edges to stop leaks.
Larger holes require metal flashing patches with mechanical fasteners into roof structure.
For rust, prime bare metal then apply sealant and elastomeric coating to problem areas.
Keep roof drainage clear and maintain sealants to prevent deterioration or rusting.
At some point, total new roof replacement becomes more cost-effective than continued repairs.

Regular inspections, cleaning, and preventative maintenance make metal roof repairs less frequent and keep roofs leak-free longer. But when repairs are needed, proper materials and procedures make the job easier. Just take appropriate safety precautions when working on your roof.