How to Install Metal Roofing Over
Plywood in Spokane WA
- By John Winston
- March 31, 2024
Metal roofing is a great option for homeowners who want a durable, energy-efficient, and stylish roof for their home. Metal roofing can last for decades, withstand harsh weather conditions, and reflect heat and sunlight away from your home. Metal roofing can also increase the value of your property and reduce your environmental impact.
However, installing metal roofing over plywood is not a simple task. You need to have the right tools, materials, and skills to ensure a successful and safe installation. You also need to follow the proper steps and precautions to avoid any damage or injury.
One of the most important steps is to prepare the plywood decking before installing the metal roofing. Plywood is a type of engineered wood that consists of thin layers of wood veneer that are glued together. Plywood is commonly used as a roof deck because it is strong, stable, and affordable. However, plywood can also be susceptible to moisture, rot, and warping, especially if it is not properly protected and maintained.
Therefore, before installing metal roofing over plywood, you need to make sure that the plywood is in good condition and that it has a suitable underlayment and slip sheet to prevent any damage or leaks. You also need to choose the right type of metal roofing for your project and install it correctly.
In this detailed guide, our team at Metal Roofing Spokane will guide you through the process of how to install metal roofing over plywood, from inspecting and repairing the plywood decking to attaching the metal panels and installing the rubber pipe boot kits.
Step 1: Check and Repair the Plywood Decking
The first step in installing metal roofing over plywood is to inspect and repair the plywood decking. You need to make sure that the plywood is in good shape and that it meets the quality standards of the American Plywood Association (APA). You also need to make sure that the plywood is smooth and flat, and that it has no obstacles or protrusions that could interfere with the metal roofing.
To inspect and repair the plywood decking, you will need the following tools and materials:
- A hammer
- A pry bar
- A circular saw
- A tape measure
- A level
- A chalk line
- A drill
- A screwdriver
- A nail gun
- A utility knife
- A broom
- A dustpan
- Plywood boards
- Nails or screws
To inspect and repair the plywood decking, follow these steps:
- Start by removing any existing roofing materials, such as shingles, felt, or tar paper, from the plywood decking. Use a hammer and a pry bar to pry off the old materials and dispose of them properly.
- Next, check the plywood for any damage, rot, or warping. Look for any signs of cracks, holes, stains, or mold. Use a circular saw to cut out any damaged or rotten plywood boards and replace them with new ones. Make sure to use the same thickness and grade of plywood as the existing ones. Use nails or screws to secure the new plywood boards to the roof rafters or trusses.
- Then, measure the length and width of the roof and mark the center point of each side. Use a tape measure, a level, and a chalk line to draw a straight line across the roof from one center point to another. This will help you align the metal panels later.
- After that, check the plywood for any raised nails, unused vents, or pipes that could cause bumps or gaps in the metal roofing. Use a hammer to flatten any raised nails, a drill and a screwdriver to remove any unused vents or pipes, and a utility knife to cut around any protrusions that need to stay on the roof.
- Finally, clean the plywood surface and remove any dust, debris, or nails that could scratch or damage the metal roofing. Use a broom and a dustpan to sweep the roof and dispose of the waste properly.
If you need professional help with inspecting and repairing your plywood decking, or any other roof repair service, don’t hesitate to contact us at Metal Roofing Spokane. We are the area’s leading provider of metal roofing services, with over 20 years of experience and expertise. We offer free estimates, quality workmanship, and customer satisfaction. Call us today at 509-822-2792 to learn more about our roof repair spokane services and how we can help you with your metal roofing project.
Step 2: Apply the Underlayment and the Slip Sheet
The second step in installing metal roofing over plywood is to apply the underlayment and the slip sheet. The underlayment is a layer of roofer’s felt or synthetic material that is laid on top of the plywood decking to provide a moisture barrier and a cushion for the metal roofing. The slip sheet is a layer of plastic or paper that is laid on top of the underlayment to provide a smooth and slippery surface for the metal roofing. The underlayment and the slip sheet are essential for protecting the plywood and the metal roofing from moisture and damage.
To apply the underlayment and the slip sheet, you will need the following tools and materials:
- A tape measure
- A utility knife
- A staple gun
- A hammer
- A nail gun
- Roofer’s felt or synthetic underlayment
- Plastic or paper slip sheet
- Staples
- Nails or screws
To apply the underlayment and the slip sheet, follow these steps:
- Start by measuring and cutting the roofer’s felt or synthetic underlayment to fit the size of the roof. Use a tape measure and a utility knife to measure and cut the underlayment. Make sure to leave some extra material for overlapping and trimming later.
- Next, lay the underlayment flat and smooth on the plywood decking, starting from the lower edge of the roof and working your way up. Overlap each row of underlayment by two inches and cut around any vents or pipes. Use a staple gun to secure the underlayment to the plywood every six inches along the edges and every 12 inches in the center.
- Then, measure and cut the plastic or paper slip sheet to fit the size of the roof. Use a tape measure and a utility knife to measure and cut the slip sheet. Make sure to leave some extra material for overlapping and trimming later.
- After that, lay the slip sheet flat and smooth on top of the underlayment, covering the entire roof area. Overlap each row of slip sheet by two inches and cut around any vents or pipes. Use a hammer and a nail gun to secure the slip sheet to the underlayment every six inches along the edges and every 12 inches in the center.
- Finally, trim any excess material from the underlayment and the slip sheet along the edges of the roof. Use a utility knife to cut the material and dispose of it properly.
Step 3: Install the Gutters, Eave Trim, and Flashing
The third step in installing metal roofing over plywood is to install the gutters, eave trim, and flashing. The gutters and downspouts are metal channels that are attached to the lower edge of the roof to collect and divert rainwater away from the roof and the foundation. The eave trim is a metal strip that is attached to the lower edge of the roof to cover the underlayment and the slip sheet and to prevent water from seeping under the metal panels. The flashing is a metal sheet that is attached to the edges, corners, and openings of the roof to seal the gaps and prevent leaks.
To install the gutters, eave trim, and flashing, you will need the following tools and materials:
- A tape measure
- A level
- A chalk line
- A drill
- A screwdriver
- A metal snips
- A hammer
- A nail gun
- A caulk gun
- A ladder
- Metal gutters and downspouts
- Metal eave trim
- Metal flashing
- Metal screws
- Nails
- Caulk or roofing cement
To install the gutters, eave trim, and flashing, follow these steps:
- Start by installing the gutters and downspouts along the lower edge of the roof. Use a tape measure, a level, and a chalk line to mark the slope and position of the gutters. Use a drill and a screwdriver to attach the gutters to the roof fascia with metal screws. Use a metal snips to cut the gutters and downspouts to fit the length and angle of the roof. Use a hammer and a nail gun to attach the downspouts to the wall with nails. Make sure to leave some space between the gutters and the roof for the eave trim.
- Next, install the eave trim along the lower edge of the roof. Use a tape measure and a metal snips to cut the eave trim to fit the length of the roof. Use a drill and a screwdriver to attach the eave trim to the roof with metal screws. Make sure to overlap the eave trim by one inch at the joints and to cover the underlayment and the slip sheet. Make sure to leave some space between the eave trim and the gutters for drainage.
- Then, install the flashing around the edges, corners, and openings of the roof. Use a tape measure and a metal snips to cut the flashing to fit the shape and size of the roof. Use a drill and a screwdriver to attach the flashing to the roof with metal screws. Make sure to overlap the flashing by one inch at the joints and to seal the gaps with caulk or roofing cement.
Step 4: Measure and Cut the Metal Panels
The fourth step in installing metal roofing over plywood is to measure and cut the metal panels. You need to measure the length and width of the roof and calculate the number and size of the metal panels needed. You also need to mark and cut the metal panels using metal snips or a circular saw with a metal-cutting blade. You need to handle and store the metal panels safely and avoid sharp edges.
- To measure and cut the metal panels, you will need the following tools and materials:
- A tape measure
- A chalk line
- A metal snips or a circular saw with a metal-cutting blade
- A pair of gloves
- A pair of safety glasses
- Metal panels
To measure and cut the metal panels, follow these steps:
- Start by measuring the length and width of the roof and dividing them by the length and width of the metal panels. This will give you the number of metal panels needed for each row and column of the roof. Round up the numbers to the nearest whole number and add some extra panels for waste and trimming.
- Next, mark and cut the metal panels according to the measurements. Use a tape measure and a chalk line to mark the metal panels where you need to cut them. Use a metal snips or a circular saw with a metal-cutting blade to cut the metal panels along the marks. Make sure to wear gloves and safety glasses to protect your hands and eyes from the metal shavings and sparks.
- Then, handle and store the metal panels safely and avoid sharp edges. Lift the metal panels carefully and avoid bending or scratching them. Stack the metal panels flat and secure them with straps or ropes. Keep the metal panels away from heat sources and moisture.
Step 5: Attach the Metal Panels
The fifth step in installing metal roofing over plywood is to attach the metal panels. You need to start from one end of the roof and work your way across, aligning the metal panels with the eave trim and the ridge line. You also need to drill holes and use galvanized metal screws to secure the metal panels to the plywood, overlapping each panel by one inch. You also need to install the ridge cap over the top of the roof to seal the gap between the metal panels.
To attach the metal panels, you will need the following tools and materials:
- A ladder
- A drill
- A screwdriver
- A hammer
- A nail gun
- A caulk gun
- Galvanized metal screws
- Metal panels
- Ridge cap
- Caulk or roofing cement
To attach the metal panels, follow these steps:
- Start by placing the first metal panel on one end of the roof, aligning it with the eave trim and the ridge line. Make sure the panel is flush with the edge of the roof and that it covers the underlayment and the slip sheet. Use a drill and a screwdriver to attach the panel to the plywood with galvanized metal screws. Space the screws about 12 inches apart along the edges and 24 inches apart in the center.
- Next, place the second metal panel next to the first one, overlapping it by one inch. Make sure the panels are aligned and level. Use a drill and a screwdriver to attach the panel to the plywood with galvanized metal screws. Repeat this process until you reach the other end of the roof.
- Then, install the ridge cap over the top of the roof, covering the gap between the metal panels. Use a drill and a screwdriver to attach the ridge cap to the roof with galvanized metal screws. Make sure to seal the joints and the screws with caulk or roofing cement.
Step 6: Install the Rubber Pipe Boot Kits
The sixth and final step in installing metal roofing over plywood is to install the rubber pipe boot kits over any vents or pipes that protrude from the roof. You need to cut a hole in the metal panel and slide the rubber boot over the vent or pipe, sealing it with caulk or roofing cement. You also need to fasten the rubber boot to the metal panel with screws or nails.
- To install the rubber pipe boot kits, you will need the following tools and materials:
- A drill
- A screwdriver
- A hammer
- A nail gun
- A caulk gun
- A utility knife
- Rubber pipe boot kits
- Screws or nails
- Caulk or roofing cement
To install the rubber pipe boot kits, follow these steps:
- Start by locating the vent or pipe that protrudes from the roof. Use a drill and a screwdriver to remove any screws or nails that secure the metal panel around the vent or pipe. Use a utility knife to cut a hole in the metal panel that is slightly larger than the diameter of the vent or pipe.
- Next, slide the rubber boot over the vent or pipe, making sure it fits snugly and covers the hole in the metal panel. Use a caulk gun to apply a bead of caulk or roofing cement around the base of the rubber boot and the vent or pipe. Press the rubber boot firmly to seal the gap and prevent any leaks.
- Then, fasten the rubber boot to the metal panel with screws or nails. Use a drill and a screwdriver or a hammer and a nail gun to attach the rubber boot to the metal panel along the flange. Make sure to seal the screws or nails with caulk or roofing cement.
Conclusion
Installing metal roofing over plywood is a great way to upgrade your home and enjoy the benefits of metal roofing. Metal roofing is durable, energy-efficient, and stylish, and it can last for decades with proper maintenance. However, installing metal roofing over plywood requires some preparation and skill, and you need to follow the right steps and precautions to ensure a successful and safe installation.
In this blog post, we have shown you how to install metal roofing over plywood in six easy steps. We have also provided you with a list of the tools and materials that you will need for the installation. By following this guide, you will be able to install metal roofing over plywood by yourself and save money on labor costs.
With a keen eye for detail and a wealth of experience in the industry, John's articles are your ultimate guide to durable, stylish roofing solutions.
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