By The Roofing Brief Team. Last reviewed: October 2026.
To cut corrugated roofing sheets, match the tool to the direction of the cut. For a lengthwise cut that runs along the panel, guide offset tin snips or electric shears through a valley (the low channel), or run a circular saw fitted with a thin-metal blade such as the 70-tooth Diablo Steel Demon, which Diablo rates for mild steel 18 gauge or thinner. For a crosscut across the corrugations, an electric nibbler or a guillotine-style shear follows the wavy profile without crushing it. Skip abrasive discs: panel makers including Lysaght and Marco Metals warn that hot filings embed in the coating and rust. Then sweep off every filing and protect the cut edge.
Corrugated roofing sheets (called corrugated iron or tin roofing in many places, though modern sheets are coated steel) are usually 29 or 26 gauge Galvalume or galvanized steel; Marco Metals rolls its Tuff-Rib panels in both gauges from AZ50 or AZ55 Galvalume. Those gauges sit well inside the rated capacity of every powered tool below, so the choice comes down to edge quality, coating damage and the paint warranty, not raw cutting power.
What is the best tool to cut corrugated metal roofing?
The best tool depends on cut direction and gauge. A nibbler is the strongest all-round pick for corrugated panels because it tracks the profile on crosscuts; the Makita JN1601 is rated for 16 gauge mild steel, far heavier than a 26 gauge panel. Tin snips handle short lengthwise cuts and notches. A circular saw with a thin-metal blade is fastest for long straight rips, but Marco Metals states that cutting its panels with circular or reciprocating saws voids the paint warranty, so check your panel maker’s terms first.
| Tool | Best for | Edge quality | Coating / heat risk | Example model and rated capacity | Source |
|---|---|---|---|---|---|
| Electric or pneumatic nibbler | Crosscuts across corrugations, curves, notches | Clean, slightly wavy kerf | Low (no heat, no sparks) | Makita JN1601: 16 ga mild steel, 18 ga stainless, 2,200 strokes per minute, 3.6 lb. Milwaukee M12 FUEL 2476-20: 16 ga mild steel, up to 7 ft per minute | Makita; Milwaukee |
| Aviation tin snips | Short lengthwise cuts, valley cuts, trimming | Clean if snips stay open | None | Left, right and straight cut pairs; Marco names offset hand snips for cuts across the profile | Marco Tuff-Rib install guide |
| Electric shears or drill-driven shear (single or double cut) | Long lengthwise cuts along a valley | Clean, narrow strip of waste | Low | Malco TurboShear HD (TSHD): 18 ga galvanized, 20 ga roofing panels, 14 ga aluminum | Malco |
| Guillotine-style panel shear | Square crosscuts on corrugated and ribbed panels | Clean, factory-like | None | Swenson Shear portable hinged shear | AEP Span field cutting guide |
| Circular saw with metal blade | Long straight rips, stacking several panels | Fast but leaves burrs | Moderate (friction heat) | Diablo Steel Demon D0770FM: 7 in, 70 teeth, mild steel 18 ga or thinner, max 8,000 RPM | Diablo |
| Angle grinder with cutoff wheel | Fast rough cuts only | Rough, heavy burr | High (sparks and coating burn) | Any abrasive (carborundum) disc | Lysaght installation manual |
For a deeper comparison of hand versus powered shears, see our guide to metal roofing shears and single versus double cut heads.
For flat trim and other profiles, see our walkthrough on how to cut metal roofing across all panel types.
Which tool for which cut? Decision table
| If you need to | Use | Why, and the source |
|---|---|---|
| Rip a 29 gauge panel lengthwise with no power tool | Score deeply down a valley with a sharp utility knife against a straightedge, then fold back and forth until it breaks | The lengthwise method in Marco Metals’ Tuff-Rib guide |
| Rip a long panel to width | Electric shears or a drill-driven shear down the valley | AEP Span rates power shears as good for cuts parallel to the ribs but difficult across them |
| Trim a short notch or a lengthwise cut under a few feet | Offset aviation snips (left, right and straight pairs) | Marco names offset hand snips; the 5 Rib guide Lowe’s hosts calls for three pairs |
| Crosscut a panel square at the eave or ridge | Nibbler, or a guillotine shear such as a Swenson Shear | Lysaght says reciprocating nibblers produce an excellent cut; AEP Span names the Swenson Shear for corrugated crosscuts at right angles to the ribs |
| Cut a stack of panels fast | Circular saw with a thin-metal blade, painted side down, over the ground | Lysaght prefers a metal-cutting blade to a carborundum disc; Marco warns saws void its paint warranty |
| Cut near panels already installed | Mask them, or aim the stream of hot particles away | Lysaght installation manual, section 7 |
| Finish a visible eave or rake cut | Never an abrasive disc or angle grinder | Filings embed and rust stain the finish (Lysaght, AEP Span, Marco) |
| Leave edges in a coastal or harsh environment | Hem the cut edge | AEP Span recommends hemming to shield cut edges |
What corrugated panel makers say about cutting
The installation documents from Lysaght, Marco Metals, AEP Span and a 5 Rib panel guide agree on abrasive discs and disagree on saws and nibblers, so read your own maker’s guide before you cut. The rows below quote each document’s position.
| Document | Recommends | Warns against | Source |
|---|---|---|---|
| Lysaght Roofing and Walling Installation Manual (BlueScope) | Power saw with a metal-cutting blade; electric shears and nibblers also suitable; colour side down; cut over the ground | Carborundum discs (more hot particles and burr); swarf left overnight | Lysaght downloads |
| Marco Metals Tuff-Rib install guide | Offset hand snips, nibbler or power shear; score and fold for lengthwise cuts | Circular or reciprocating saws, which void the paint warranty; if used, cut bottom side up | Marco install guide |
| AEP Span field cutting guide | Aviation snips, sheet metal shears, Swenson-type guillotine shear, power shears for parallel cuts | Sawing and abrasive cutting; notes nibblers struggle to cut straight and over ribs | AEP Span |
| 5 Rib Metal Roofing System guide (hosted by Lowe’s) | Electric nibblers or metal shears; three pairs of snips | Abrasive saw blades: jagged edges, hot filings, burnt paint and galvanizing at the cut | 5 Rib guide PDF |
Cutting along the corrugations (the lengthwise cut)
A lengthwise cut runs parallel to the ribs, usually to narrow a panel to width. Always cut through a valley, the low flat channel between ridges, never across a raised rib. The valley gives snips or shears a flat path and keeps the ridge pattern intact so the next panel still laps correctly; on a 29 gauge panel the Marco Metals score-and-fold method also works in a valley.
- Measure and mark the cut line in chalk down the center of a valley, not on a ridge.
- Support the panel on two sawhorses with the cut line hanging just past the edge of a board.
- For a hand cut on a 26 or 29 gauge panel, open aviation snips wide and take long bites, keeping the jaws from fully closing so the edge stays straight rather than crimped.
- For a powered cut, run electric shears with the panel painted side up. For a circular saw with a 70-tooth thin-metal blade such as the Diablo Steel Demon D0770FM, turn the panel painted side down, as Lysaght and Marco both specify, so hot shavings land on the back.
- Check the ridge either side of the cut is undamaged so the panel still nests with its neighbor.
Cutting across the corrugations (why a nibbler wins)
A crosscut runs perpendicular to the ribs, the cut you make to trim panel length at the eave or ridge. Tin snips crush the ribs flat and a circular saw grabs as it climbs each corrugation, while a nibbler punches out a small chip with each stroke (a 1/4 inch stroke on the Makita JN1601) and rides over every rib. AEP Span’s alternative is a guillotine-style Swenson Shear, which it names for corrugated crosscuts at right angles to the ribs. Before buying a nibbler for a deep profile, compare the nibbler rib-depth and radius specs by model.
- Mark the crosscut line across the ridges and valleys with a square and chalk.
- Fit the nibbler and start at one edge, letting it feed itself along the line; Milwaukee rates its M12 FUEL 2476-20 at up to 7 feet per minute in 16 gauge steel, so a 3 foot wide sheet takes well under a minute.
- Follow the corrugation up each ridge and down each valley rather than forcing a flat path.
- If you only own snips, which is how most people cut corrugated iron by hand, cut each valley with the snips, then snip down the sloped sides of each rib with the left and right offset snips Marco Metals names, and file the slightly ragged edge.
- Clear the small crescent chips the nibbler ejects, since they are sharp and rust fast on the roof surface.
Should you use an angle grinder on corrugated panels?
An angle grinder with an abrasive cutoff wheel cuts corrugated metal fast, but it is the worst choice for a finished roof. The wheel throws hot steel particles that land on the coating, embed, and bloom into rust spots often called tea staining, and the Lysaght Roofing and Walling Installation Manual says a metal-cutting saw blade produces fewer damaging hot particles and less burr than a carborundum disc. The 5 Rib guide adds that abrasive cutting burns the paint and galvanizing at the cut edge. Reserve the grinder for hidden cuts or scrap.
If a grinder is the only tool available, cut with the panel face down so sparks fall away from the finished side, cut over the ground rather than over other sheets (a rule in section 7.3 of the Lysaght Roofing and Walling Installation Manual), and wipe or blow every particle off the surface before the panel goes up. A cold cut from a nibbler or shears avoids the problem entirely and is the standard on any visible run.
How do you stop the cut edge from rusting?
Cut-edge corrosion is the corrugated-specific failure most guides skip. Bare corrugated panels are usually galvanized steel (ASTM A653) or Galvalume (ASTM A792), not the thick PVDF paint on architectural standing seam. Cleveland-Cliffs’ GALVALUME data sheet says the zinc in the coating gives galvanic cut-edge protection while the aluminum stays as a barrier, and AEP Span notes that a sheared cut can fold a little coating over the bare edge, which a sawn or ground edge cannot. A ground, filed or sawn edge still benefits from a re-coat.
- Deburr the fresh edge with a flat mill file or a light pass of a deburring tool so no sharp sliver remains.
- Wipe the edge clean of swarf, oil, and chalk.
- Brush or spray a zinc-rich cold galvanizing compound along any cut, notch, or drilled hole that will be exposed to weather.
- Touch in visible eave and rake cuts with color-matched roof paint; our corrugated metal roof colors and finishes guide helps you match it.
Panels destined for the ridge, eave, and end laps all get factory edges hidden under flashing, so the edges that matter most for rust are your field cuts. Lysaght tells installers to sweep or hose all swarf off the roof and out of the gutters at the end of each day, and on critical jobs to inspect again 14 days after completion, when rain will have rusted any filing that was missed. For panel dimensions and lap detail before you cut, see our reference on corrugated roof panel sizes and materials.
Safety gear and cutting setup
Corrugated cutting produces razor edges, flying chips, and, with powered tools, high noise. The 5 Rib installation guide calls eye protection and gloves a must with sheet metal and hearing protection for power cutting, and Lysaght recommends heavy-duty cut-resistant gloves for handling. Wear wraparound safety glasses, cut on stable sawhorses at waist height, never freehand on the roof, and keep the offcut supported so it does not fold back and slice your forearm.
- Gloves: cut-resistant, since a fresh panel edge slices skin as easily as a blade.
- Eyes: sealed safety glasses or goggles against hot chips and swarf.
- Ears: plugs or muffs for grinders, saws, and pneumatic nibblers.
- Setup: two sawhorses, a straightedge clamp for long rips, and a broom to clear sharp debris.
For cost, lifespan and install, start at the hub guide to corrugated metal roofing, part of Learn About Roofing.
Frequently asked questions
What is the best tool to cut corrugated metal roofing?
An electric nibbler is the best all-round tool because it follows the wavy corrugated profile without crushing the ribs, which matters most on crosscuts; the Makita JN1601 is rated for 16 gauge mild steel, well above a 26 or 29 gauge panel. For long lengthwise cuts down a valley, tin snips, electric shears, or a circular saw with a thin-metal blade all work. Match the tool to the cut direction.
Do you cut corrugated metal roofing along the ridges or the valleys?
Cut lengthwise cuts along the valleys, the low flat channels between ridges, never along the raised ridges. The valley gives a flat, supported path so snips or shears leave a straight edge and the ridge pattern stays intact for the panel to lap. On 29 gauge panels, Marco Metals also allows scoring the valley with a utility knife and folding it until it breaks.
Can you cut corrugated metal roofing with tin snips?
Yes, aviation tin snips cut 26 and 29 gauge corrugated panels well for short lengthwise cuts, valley cuts, and trimming. Keep the jaws from closing fully on each bite so the edge stays straight rather than crimped. Snips struggle on long crosscuts across the ribs because they flatten the corrugation, so switch to a nibbler for those cuts.
Can you use an angle grinder to cut corrugated metal roofing?
You can, but it is the worst option for a visible roof. The Lysaght Roofing and Walling Installation Manual says a carborundum disc throws more damaging hot particles and leaves more burr than a metal-cutting blade, and those particles rust into tea staining. If you must use one, cut face down over the ground and clear every particle. A cold cut from a nibbler or shears is the standard for finished panels.
How do you cut corrugated metal roofing without rusting the edge?
Deburr the fresh edge, wipe off swarf, then brush or spray a zinc-rich cold galvanizing compound on any exposed field cut, notch, or drilled hole. Per Cleveland-Cliffs, the zinc in a GALVALUME coating gives galvanic cut-edge protection, but ground or sawn edges still benefit from a re-coat. Sweep all filings off the roof at the end of each day, as Lysaght specifies.
Can you cut corrugated metal roofing with a circular saw?
Yes, with a thin-metal blade such as the Diablo Steel Demon D0770FM (70 teeth, mild steel 18 gauge or thinner), never a wood blade, and with the painted side down. Check your panel maker first: Marco Metals says circular or reciprocating saws void its paint warranty. Use a nibbler instead for crosscuts across the corrugations, where a saw tends to grab.
Which side up do you cut corrugated roofing sheets?
With a saw or grinder, cut painted side down: the Lysaght Roofing and Walling Installation Manual says the exterior colour finish is best facing down and Marco Metals says to cut bottom side up so hot shavings miss the painted face. With snips, shears or a nibbler, which throw no hot particles, either side works; mark the line on the side you can see best.