August 10, 2026
Corrugated metal roofing is a project you can finish in a weekend with basic tools and careful planning. To install it, you need to measure your roof, prepare the deck, lay the panels with the correct overlap, and seal every edge with proper flashing. Each step matters. Skipping one can lead to leaks or panels that come loose over time.
Before you start, you need the right materials and safety gear. You also need to know how many panels to buy and where to place fasteners so your roof holds up in wind and rain. This guide walks you through each stage, from measuring your roof to checking your finished work.
Metal roofing lasts for decades when installed correctly. You'll learn how to avoid common mistakes and get a roof that sheds water and stands up to the weather.
Good planning starts with checking your roof's condition and pitch, then working out exact material amounts before you order anything. You also need to confirm your project meets local codes so you don't run into problems later.
Check your roof's pitch before you buy any materials. Most corrugated metal panels need a minimum slope of 3:12 (3 inches of rise for every 12 inches of run) to shed water properly.
Use a level and tape measure to find your pitch, or check your building plans if you have them. A steeper pitch sheds water and snow faster, while a low slope needs extra sealant and closer panel overlaps.
Next, inspect the roof deck and framing. Look for:
Fix any structural issues before you install new roofing. Metal panels are heavy enough that weak framing can fail under the added weight and normal wear over time.
Measure the length and width of each roof section, then multiply to get the square footage. Add 10% extra to cover waste from cuts and overlaps.
Corrugated panels come in standard widths, but only part of each panel is usable due to side overlaps. Check your panel's "effective coverage width" (usually listed by the manufacturer) rather than its full width when calculating how many you need.
For fasteners, plan on one screw per corrugation ridge at each purlin, plus extra along edges and end laps. A typical roof needs about 30 to 40 screws per 100 square feet, depending on panel spacing.
You'll also need:
Order 5-10% more flashing material than your initial measurements suggest, since cutting and shaping often creates waste.
Contact your local building department before starting work. Many areas require a permit for roof replacement or major repairs, even for DIY projects.
Codes often specify:
Some regions also have rules about installing new metal roofing over existing shingles versus requiring a full tear-off. Skipping this step can lead to fines or problems when you try to sell your home later.
If you're unsure what applies to your project, call your local permit office directly. They can tell you exactly what inspections you'll need and when to schedule them during the installation process.
A good corrugated metal roof starts with the right gear. Before you climb up on that roof, make sure you have the correct tools, the right panels and fasteners, and safety equipment that fits properly.
You need a few specific tools to cut and attach corrugated panels correctly.
Cutting tools:
Fastening tools:
Measuring and layout tools:
Skip using an angle grinder to cut panels. It heats the metal edges and can strip away the protective coating, which leads to rust later on.
Your roof needs more than just metal panels. Here's what to buy before you start:
ComponentPurposeCorrugated metal panelsMain roofing surfacePurlins or roof deckingStructural base for panelsUnderlayment (synthetic or felt)Moisture barrier under panelsSelf-tapping screws with rubber washersFasten panels without leaksClosure stripsSeal gaps at ridges and eavesRidge capCovers the roof peakSealant or butyl tapeSeals overlaps and seams
Buy panels that are long enough to span your roof in one piece when possible. This cuts down on overlaps and lowers the chance of leaks. Always order 10% extra material to account for cutting waste and mistakes.
Roof work carries real risk, so safety gear is not optional. At a minimum, you need a fall arrest harness connected to a secure anchor point rated for your body weight.
Wear rubber-soled boots made for walking on metal. Regular sneakers or work boots don't grip corrugated surfaces well, especially when they're wet or dusty.
Other required safety items include:
Check the weather before you start. Never install metal roofing in rain, high wind, or extreme heat, since wet panels get slippery and hot metal can burn bare skin. Morning hours in cooler weather are usually your safest and most comfortable window for this work.
A solid deck is the foundation of a leak-free roof. You need to check the structure, fix any weak spots, and add the right layers before a single metal panel goes on.
If you have old roofing material, decide whether to remove it or roof over it. Most local codes only allow one layer of overlay, so check your rules first.
Removing the old roof lets you see the deck clearly. Look for soft spots, water stains, or rotted wood. These signs point to damage that needs fixing before you move forward.
If you choose to leave the old roofing in place, make sure it's flat and secure. Loose shingles or uneven spots can cause the new metal panels to sit wrong. Take time now to catch problems early, since they get harder to fix once the roof is covered.
Walk the entire deck and press down on each area to check for soft or bouncy spots. Replace any damaged plywood or boards with new material that matches the existing thickness. Use screws instead of nails for a tighter hold.
Once repairs are done, install synthetic underlayment across the whole deck. This layer adds a barrier against moisture and helps prevent leaks.
Start at the lowest edge of the roof and work upward. Overlap each row by at least 4 inches. Staple or nail the underlayment every 12 inches to keep it flat and secure.
Trim pieces guide water off the roof and give the edges a clean, finished look. Install eave trim first along the lowest edge of the roof. This piece directs runoff into the gutter instead of behind the fascia.
Next, add rake trim along the sloped edges on each side. This keeps wind and rain from getting under the panels.
Use roofing nails or screws spaced about every 12 inches. Make sure each piece overlaps the next by 2 to 3 inches to keep water from sneaking through the seams. Check that all trim is straight and level before moving on, since crooked trim can throw off your first row of panels.
Getting your first panel straight sets the pace for the whole roof. Every panel after that depends on correct overlap and careful screw placement to keep water out and panels intact.
Start at one corner of the roof, usually the end farthest from prevailing wind.
Line up the panel edge with the eave. Let it hang over the edge by about 1 to 2 inches. This overhang stops water from running back under the roof.
Check the panel is square before you fasten anything. Use a square or measure from the ridge to the eave on both sides of the panel. The distances should match.
If the panel sits crooked, every other panel will be crooked too. Take a few extra minutes here. A small error at the start turns into a big gap by the last panel.
Once it's square, drive one or two screws to hold it in place. Don't fully fasten it yet.
Panels need to overlap by one full corrugation, sometimes called a rib. This is usually about 1.5 to 2 inches, depending on your panel style.
The direction of the overlap matters more than the size. Lay each new panel so it overlaps the previous one facing away from the prevailing wind direction. This keeps wind-driven rain from getting under the seam.
Here's a quick way to check your layout:
If you're working on a roof with a ridge, panels on each side should overlap at the top by at least 6 inches. Seal this ridge overlap with roofing sealant or a closure strip to block water and pests.
Use self-tapping screws with rubber or neoprene washers made for metal roofing. These seal the hole and stop rust.
Drive screws into the flat part of the panel, not the raised ribs. On the flats, screws go into the roof deck or purlins below and hold tight. Screws on the ribs often miss the framing and leave gaps.
Don't overtighten. A screw driven too hard squeezes the rubber washer flat and cracks it, which lets water in. Stop as soon as the washer flattens slightly against the metal.
Space screws about every 12 inches along the panel's length on the flats where it crosses each purlin. Along the overlap seams, place screws every 8 to 10 inches for a tighter seal.
Check every few screws with your hand. If you feel the panel lift or wobble, it means the screw is too loose or missed the framing.
Flashing and sealing are what keep water out of your roof system. If you skip steps here or rush the work, you will likely deal with leaks later.
The ridge cap covers the gap where two roof slopes meet at the top. You need to install it after both sides of the roof are fully panel and fastened.
Start by cutting foam closure strips to match the shape of your corrugated panels. Place these strips under the ridge cap on both sides of the peak. They block wind, dust, and water from getting under the cap while still letting some airflow through.
Once the closures are in place, set the ridge cap over the peak. Fasten it with the same type of screws you used on the panels, spaced about every 12 inches. Apply a bead of sealant along the underside edges before you screw it down for extra protection.
Valleys, sidewalls, and endwalls are common spots for leaks because water collects and moves in different directions at these points. Each area needs its own flashing type.
For valleys, install a metal valley flashing piece before you lay panels on either side. This piece should extend under the roofing panels by at least 6 inches on each side.
Sidewall flashing goes where the roof meets a vertical wall, like a dormer. Endwall flashing covers where the roof ends at a wall running perpendicular to the slope. Both types should tuck under the wall covering, such as siding, and lay over the top of the roof panels.
Flashing TypeLocationOverlap NeededValleyWhere two slopes meet6+ inches each sideSidewallRoof meets vertical wall (parallel)4+ inches under sidingEndwallRoof meets wall (perpendicular)4+ inches under siding
Foam closures fill the wavy gaps left by the corrugated shape of the panels. Without them, pests, water, and wind can get under your roof edges.
Install foam closures at the eaves, ridges, and any place where panels meet flashing. Cut them to match the exact wave pattern of your panels so they fit snugly.
After the closures are set, add a bead of sealant along all flashing edges and panel overlaps. Focus on screw heads, panel seams, and joints where two flashing pieces meet. Use a sealant rated for outdoor metal use, since regular caulk can crack or peel off within a year or two.
A finished metal roof needs a final check before you call the job done. Regular care after that keeps the roof strong for many years.
Walk the roof or use a ladder to check every screw. Each fastener should sit flush with a slight compression on the rubber washer. Screws that are too tight will crack the washer. Screws that are too loose will let water in.
Check the overlaps between panels. They should be tight with no gaps you can see light through.
Look at the drainage path too. Water should flow freely toward the gutters with nothing blocking the flow. Check these spots:
Clear away any leaves, dirt, or debris that could trap water on the surface.
Rinse the roof with a garden hose at least twice a year. This removes dirt, pollen, and other buildup that can trap moisture against the metal.
Avoid pressure washers. They can force water under panels or strip the protective coating.
Check for scratches in the paint or coating. Bare metal spots can rust over time, especially near cut edges or fastener holes. Touch up any exposed metal with a matching paint made for metal roofs.
If you live near the coast, rinse more often. Salt in the air speeds up corrosion. Also check for rust near dissimilar metals, like where steel screws meet aluminum panels, since this contact can cause faster wear.
Check your roof at the start of spring and fall. These two seasons show damage from winter cold and summer heat.
Look for these common issues during each inspection:
SeasonWhat To CheckSpringLoose fasteners from winter freeze-thaw, ice damageFallDebris buildup, loose flashing before winter storms
After any major storm with high wind or hail, do an extra check. Look for dents, loose panels, or damaged flashing.
Keep a simple log of each inspection date and what you found. This record helps you track wear patterns and plan repairs before small problems turn into bigger ones.
Below are answers to common questions about tools, materials, fastening, and overlap for corrugated metal roofing.
You need corrugated metal panels, a vapor barrier or underlayment, and roofing screws with rubber washers.
You'll also need closure strips, ridge caps, and flashing for edges and valleys. For tools, gather a drill or impact driver, tin snips or a metal-cutting circular saw blade, a chalk line, tape measure, and safety gear like gloves and eye protection. A caulking gun with roofing sealant helps seal seams and fastener points.
Start by checking that the shed's roof deck is solid, level, and free of rot.
Roll out underlayment across the deck, then attach a drip edge along the eaves. Lay your first panel at a bottom corner, keeping it square with the edge. Work across the roof one panel at a time, overlapping each new panel over the last. Fasten as you go, then finish with ridge cap at the top for a sealed edge.
Yes, plywood makes a solid base for corrugated metal panels.
You should add an underlayment layer between the plywood and the metal first. This barrier protects the wood from moisture and helps the panels last longer. Skipping this step can lead to trapped moisture and wood rot over time.
Side overlaps should cover at least one full corrugation, sometimes two on windy sites.
For end overlaps, where one panel meets another going up the roof slope, plan for 6 to 8 inches of overlap. Steeper roofs can use the smaller end of that range, while low-slope roofs need more overlap to keep water out. Always check your panel manufacturer's specs, since overlap requirements can vary by product.
Drive roofing screws with rubber washers through the raised part of each corrugation, not the low points.
Space fasteners roughly every 12 inches along the ridges, and add extra screws along panel edges and overlaps. Don't overtighten, since this can crush the rubber washer and let water in. Set the drill's clutch so screws stop right when the washer seals flat against the panel.
One frequent mistake is fastening through the low points of the panel instead of the raised ridges, which causes leaks.
Another issue is skipping or skimping on overlap, especially at panel ends where water runoff is heaviest. Some installers also forget underlayment, leaving the wood deck exposed to moisture. Misaligned panels are common too, so always start with a square first panel and check alignment as you go. Finally, using the wrong screws or missing washers can shorten the roof's lifespan significantly.
