How to Overlap Corrugated Metal Roofing Panels – PNW Installation Guide
Proper corrugated metal roofing overlap is essential for waterproofing, wind resistance, and structural strength.
In the Pacific Northwest’s rainy, coastal climate, correct panel installation prevents leaks, rust, and long-term damage.
Follow these industry best practices for DIY roofing and siding projects.
📌 Tap each section below to expand step-by-step tips
✅ Why Proper Overlap Matters – Tap to Expand
Correct overlap between panels prevents:
✔ Water leaks – keeps rain from seeping under panels
✔ Wind lift – stops panels from peeling in high PNW winds
✔ Rust & condensation – avoids trapped moisture
✔ Structural weakness – ensures panels act as a solid, reinforced surface
✅ How Much Should Panels Overlap? – Tap to Expand
Recommended by Metal Construction Association (MCA) & National Roofing Contractors Association (NRCA):
✔ Side Overlap: Minimum of 2 ribs to ensure tight water seal
✔ End Overlap:
– Low-slope roofs (<3:12): 6 inches + sealant
– Steep-slope roofs (>6:12): 4 inches
✔ Roof Pitch: Lower pitches require extra sealing and fasteners
📏 How to Calculate Panel Coverage – Tap to Expand
Using our 26.5-inch factory-cut panels:
✔ Roofing: With 2-rib overlap, effective coverage = ~22 inches per panel
✔ Walls: With 1-rib overlap, effective coverage = ~24 inches per panel
Formula:
– Roof width (inches) ÷ 22 = number of roofing panels
– Wall width (inches) ÷ 24 = number of wall panels
Note: End overlaps reduce usable length; order extra panels if unsure.
✅ Using Corrugated Panels for Fencing – Tap to Expand
✔ **Post Spacing:** 6–8 ft apart for strong support
✔ **Overlap:** At least 1 rib to resist wind & rain
✔ **Fasteners:** Use galvanized or stainless screws with neoprene washers
✔ **Treated Lumber Note:** Place a barrier between panels and pressure-treated posts to prevent staining or corrosion
✔ **Wind Resistance:** Consider extra bracing in exposed coastal or rural areas
🛠 Proper Screw Placement – Tap to Expand
✔ Install screws on **rib tops, not valleys** to prevent water pooling
✔ Perimeter edges: **6–12 inches spacing** for wind resistance
✔ Center of panels: **24–36 inches spacing** depending on wind load
✔ Overlaps: Fasten **1–2 inches from rib edge** to secure joints
✔ Always use **self-sealing screws with neoprene washers**
✅ Cutting & Safety Tips – Tap to Expand
✔ Wear **ANSI A4-rated cut-resistant gloves** to prevent injuries
✔ Use **aviation snips, electric shears, or metal saw blades** – avoid abrasive grinders
✔ Mark cut lines clearly & cut on stable surfaces
✔ File sharp edges to reduce injury risks
✅ Preventing "Tin Canning" – Tap to Expand
✔ Use **thicker gauge panels (29 or 24 ga)** to reduce oil canning
✔ Avoid over-tightening screws – allow for **thermal expansion**
✔ Store panels flat & handle carefully to avoid pre-installation bends
📞 **Order Factory-Cut Panels for PNW Projects Today!**
Call 360-916-8312 or request a custom quote.
**Perfect for Pacific Northwest rain, coastal winds, and DIY builders!**
