To lap corrugated metal roofing, you need to overlap each sheet by at least one full corrugation to prevent water leaks. Metal roofing is growing in popularity because it lasts 40 to 80 years, much longer than asphalt shingles. According to RubyHome (2025), corrugated metal costs between $5.50 and $11.50 per square foot when installed. The lapping process is simple but must be done correctly. Getting this step right means your roof will shed water properly and last for decades.
Why Lap Corrugated Metal Roofing?
Water runs downhill on your roof. If sheets do not overlap enough, water can sneak into the gaps and damage your home. Metal roofing remains popular because it handles heavy rain and hail well.
According to the Metal Roofing Alliance (2024), metal roofing holds 17% market share in residential roofing. Proper lapping protects your investment.
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How Much Overlap Do You Need?
Overlap one full corrugation minimum. One full corrugation means the entire wave pattern of one ridge and valley. This is the industry standard.
In windy areas or steep roofs, use two corrugations. More overlap keeps wind from getting under the sheets. Measure twice, cut once.
Step-by-step Lapping Process
Start at the bottom of your roof and work up. Slide the second sheet under the first sheet by one corrugation. Fasten with metal roof screws, not nails.
Use screws with rubber washers. Place screws at the top of each corrugation. Space screws 12 to 18 inches apart along the lap.
Do not over-tighten screws. They should be snug, not squeezed hard. According to corrugated metal installation guides, over-tightening causes leaks by warping the metal.
Common Lapping Mistakes to Avoid
| Mistake | What Happens |
|---|---|
| Too little overlap | Water leaks through gaps |
| Overlap on wrong side | Water runs under the sheet |
| Using nails instead of screws | Fasteners rust and pull out |
| Over-tightening screws | Metal warps and leaks form |
According to industry data, metal roofing can last 40 to 80 years with proper installation. The lapping step is where most mistakes happen. Take your time and measure carefully.
Always overlap from bottom to top. Always use the downhill sheet on top. According to RoofLink (2025), standing seam metal panels cost $10.00 to $17.05 per square foot, making them an investment worth protecting. Correct lapping keeps water out and keeps your roof working for decades.
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Connect with an experienced roofing services to discuss your roofing needs and schedule an inspection.