Simple Guide on How to Install Metal Roofing over Plywood

It is common for the modern roof to come with several layers. Now, if your plywood roof is currently sagging or rooted, there’s a great chance you have to fix it as soon as possible. The guide below will tell you how to install metal roofing over plywood.

How to Install Metal Roofing Over Plywood in 8 Steps

You may wonder why you should use metal roof replacement. Metal is considered a wise roofing material choice nowadays, considering its visual and functional aspects. Among various types of roofing, metal stands out for its durability and aesthetic appeal.

how to install metal roofing over plywood

The metal roof needs to have a solid deck structure. Plywood is what do you put under metal roofing to support the metal panels’ weight. However, it would help if you first ensured that the plywood is clean enough to be free from raised nail heads. Before installing the metal panels, it’s essential to apply the underlayment for added protection.

Read also: How to Build a Metal Roof Over a Deck

Follow these steps on installing metal roofing over plywood after you ensure it is already clean and all the nails are hammered down.

  1. Set the waterproof plywood on the flat surface of your roof. Each row must be overlapped by a couple of inches and cut to fit the protrusions’ base. Secure with roofing nails and hammer. Using a slip sheet between the metal roofing and plywood can provide additional protection against moisture.
  2. Calculate your roof edge’s length. Then cut the metal flashing and install it on the edge of the roof by using a nail and hammer. Install the gutters according to the fitted size, then secure them by using a hammer and nails.
  3. Draw a vertical line about 0.25 inches away from the rake edge. Work by starting from the left to the right side of the roof. Set the metal panel on the bottom corner to the roof’s ridge, with 1-inch overlaps between each edge. Then use a galvanized metal screw to secure the roof panel to the deck in a distance of 16 inches or 12 inches between each other.
  4. The next step is to line up the second panel over the first panel straight. Their edges must overlap by about 12 inches. Secure the metal roofing panel at a distance of 16 inches or 12 inches between each other of the deck using a galvanized metal screw.
  5. Continue step 4 until you arrive at the roof’s peak. Calculate the length required to reach the last upper panel and mark it by using a pencil. Then cut the metal panel accordingly using metal snips.
  6. Come back to the bottom corner of the roof. Start to install another metal roofing panel row. Set the rib on the left part of the metal panel to the right part of the next installed metal panel’s rib.
  7. Again, continue step 7 for every row until you have installed all panels.
  8. Finally, set the ridged metal on the highest point of your roof, and install kits of pipe boot throughout the vent pipes.

Read also: Metal Roof Flashing Types

Prefer not to use underlayment will only save you some budget in short term, from several hundred to one thousand dollars – depending on your house’s size.

If you follow the steps on installing metal roofing over plywood, you might save thousands of dollars in the future instead.

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RoofLast is an experienced author and roofing expert. With years of practical experience in the field authored several informative articles on various aspects of roofing, including installation, maintenance, and repair