Metal roofs typically hold up well against leaks, but corrugated metal roofs can become vulnerable to moisture penetration. The individual panels are attached using steel nails or screws. If your corrugated roof is leaking, it's possible the nails or screws rusted or came loose. Educate yourself on how to fix a leak if your corrugated metal roof becomes compromised.
First, you'll need to find the source of the leak, then you can determine the best method to fix it.
Make sure you’ve got the right materials for the job.
Here's what you'll need:
- Extension ladder
- Nail bar and hammer
- Wire brush
- Cordless drill
- Urethane roof cement
- Metal roofing base coat
- Glass membrane fabric roof patch
- Putty knife
- 1½-inch aluminum screw nails
- 1-inch galvanized steel screws
Repairing Loose/Missing Fasteners
Loose or missing fasteners are a common culprit for leaking corrugated metal roofs.
Quick repair is key in order to prevent moisture penetration. Here's a step-by-step breakdown of the loose fastener repair process.
Step 1: Inspect all the fasteners.
Carefully climb up on the roof and inspect the fasteners. To avoid bending the metal panels, look at each row of nails by walking on the row instead of between them.
Step 2: Pull up compromised rails.
With a crowbar, pull out any nails that aren’t flush with the metal panel. Replace the compromised nail with a 1½-inch aluminum nail. Use a hammer to drive the new nail into place. If the panels are installed with screws, and you notice rusted-away screw heads, use a drill to attach 1-inch galvanized screws as close as you can to the compromised screw.
Step 3: Don’t be shy with roof cement.
Apply a liberal amount of urethane roof cement on any new nail or screw, and smooth out all applications with a plastic putty knife or your thumb.
Step 4: Look closely at all flashings.
Look carefully at all the caulked seams around flashings and roof protuberances. If you see cracked caulk, remove it with a wire brush, and apply a new, steady line of urethane roof cement.
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Repairing Roof Panel Edges
Gaps along the panel edges of a corrugated metal roof are another common source of leaks. Sealing these gaps will ensure rain, snow, and debris stay out of the interior roof system.
Step 1: Look for gaps.
Look for gaps where the metal panels overlap one another. Separation as small as 1/8 of an inch can cause leaks during hard rainstorms.
Step 2: Clear away debris.
Clear away rust and debris from the panel’s surface using a wire brush. Make sure you have a metal roofing base coat, and apply a uniform layer at least 6 inches in each direction from the spot of the gap.
Step 3: Cover with fabric and roof cement.
Cut a swath of glass membrane fabric to size and cover the base coat with it. After it’s securely in place, apply a coat of urethane roofing cement over the fabric to help complete the seal.
Hiring an Experienced Roofing Contractor
Metal roofs require a certain amount of patience and specific tools in order to repair them correctly. Not to mention, you should feel comfortable and confident on top of your roof. If you don't have the necessary materials, time, or confidence, it's best to hire a responsible and experienced roofer to handle the repair for you.