How To Install Metal Roofing Over Plywood

November 28, 2025

2 min read

dilshadakram

To install metal roofing over plywood, you need to prepare the surface, add underlayment, and then fasten the metal panels securely. Metal roofing is one of the most durable options available today. According to industry data, metal roofing lasts 40 to 80 years, making it a smart long-term investment for homeowners. The process takes planning and the right tools, but many homeowners can do it with help. This guide walks you through each step to get your metal roof installed correctly.

Step 1: Check Your Plywood and Prep the Surface

First, inspect your plywood for damage, rot, or soft spots. Replace any bad sections before you start. Your plywood must be solid and flat. Remove any nails, debris, or old roofing material sticking up.

Make sure the surface is clean and dry. Sweep off dirt and leaves.

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Step 2: Install Underlayment

Underlayment goes between the plywood and metal panels. It protects against water, wind, and condensation. Roll out the underlayment from the bottom edge upward. Overlap each row by 6 inches. Nail or staple it down every 12 inches.

This extra layer is key to a long-lasting roof. According to RubyHome, standing seam metal panels cost $10 to $17.05 per square foot installed, and that price includes labor. The underlayment is worth the extra effort.

Step 3: Mark Your Layout and Snap Lines

Use chalk to snap lines across your roof. These guide where your first panel goes. Measure from the edge and mark every 12 to 24 inches, depending on your panel width. Start at the edge closest to the ground and work upward.

Straight lines mean straight panels and better water drainage.

Step 4: Fasten Panels and Seal Edges

Start at the lowest edge and work your way up. Use metal roofing fasteners (usually screws with rubber washers) to attach each panel. Follow the manufacturer’s spacing guide, normally every 12 to 16 inches. Do not over-tighten, as this can damage the rubber washer.

Seal all joints and overlaps with roofing sealant. According to RubyHome, roof installation costs range from $4 to $40 per square foot depending on material choice. Proper sealing prevents leaks and extends your roof lifespan. According to the National Association of Home Builders, the average U.S. roof size is 26.47 squares (2,647 square feet). Plan your fastening pattern to match your exact roof size.

Metal Roofing Type	Cost Per Sq. Ft.	Lifespan
Standing Seam Metal Panels	$10.00, $17.05	40, 80 years
Corrugated Metal	$5.50, $11.50	40, 80 years
Steel Shingles	$8.00, $12.65	40, 80 years

Metal roofing over plywood is a solid choice. According to industry data, metal roofing holds about 10 percent market share in U.S. residential roofing. The durable material handles storms well and adds value to your home. Take your time with each step, and your metal roof will serve you for decades.

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Contact a qualified roofing company for expert guidance on roof repair, replacement, or installation.