What kind of saw blade to cut metal roofing?

When it comes to cutting metal roofing, having the right saw blade is crucial for getting clean and precise cuts. The type of saw blade you need depends on a few factors, including the type of metal you’re cutting, the thickness of the roofing material, and what kind of cuts you need to make.

Circular Saw Blades for Metal Roofing

For most metal roofing jobs, a circular saw with a specialized metal cutting blade will be the best option. Here are some things to consider when choosing circular saw blades for cutting metal roof panels and sheets:

• Carbide-tipped vs. high-speed steel – Carbide-tipped blades stay sharper for much longer than high-speed steel. Carbide is extremely hard and holds its edge even when cutting abrasive metals like galvanized steel or aluminum.
• Number of teeth – Blades with more teeth (e.g. 80+ teeth) provide a smoother cut. Lower tooth counts are more aggressive for faster cutting.
• Angle of teeth – Look for a blade with teeth optimized for cross-cuts. An alternating top bevel (ATB) is common.
• Coating – A PTFE or titanium coating helps the blade run cooler and resist material buildup during cutting.
• Diameter – 7-1/4 inch blades are common for portable circular saws. 10+ inch blades are used for table saws or chop saws.
• Arbor size – This must match your tool. Most circular saws use 5/8″ or 1″ arbor sizes.

For thin sheet metal, a fine-toothed carbide blade is ideal to prevent tearing or leaving burrs on the cut edge. For thicker roofing panels, a blade with fewer teeth will cut faster and more efficiently.

Jigsaw Blades for Metal Roofing

For curvy cuts and cutouts, a jigsaw with a metal-cutting blade is the perfect tool. Here are some tips for selecting jigsaw blades for metal roofing projects:

• Tooth design – Look for coarse teeth optimized for fast cuts and minimal burring in thicker gauges of metal.
• Variable tooth count – Blades with teeth that alternate between large and small help prevent jamming when cutting metals.
• Coating – A PTFE or titanium coating will keep the blade cooler. This prevents premature wear.
• TPI – For sheet metal and thin aluminum, use fine TPI blades (at least 18 TPI). For steel roofing, 10-14 TPI is ideal.
• Shank – Make sure the shank is the correct size to fit your jigsaw.

One option is to use a dedicated metal cutting jigsaw blade. Bi-metal blades (carbide teeth brazed to spring steel) are long lasting for roofing jobs.

Reciprocating Saw Blades for Metal Roofing

For quickly cutting through thick, corrugated steel roof panels, a reciprocating saw (also called a hacksaw or Sawzall) fitted with a long metal-cutting blade is extremely effective. Here are tips for choosing the best reciprocating saw blades for metal roofing:

• Tooth design – Look for an aggressive tooth pattern with large gullets for fast cuts and maximum efficiency in thicker gauges of steel.
• TPI – For metal roof panels, a blade with 14 teeth per inch (TPI) is a good choice. You can go up to 18 TPI for good cut quality.
• Length – Long 12-14 inch blades give you extended reach for cutting wide roofing panels from the top.
• Coating – A cobalt or titanium coating will keep the blade running cool. Friction and heat will quickly dull uncoated blades.

Bi-metal reciprocating saw blades combine the hardness of high speed steel teeth with the flexibility of spring steel. This creates durable, long lasting blades for all types of metal cutting.

Abrasive Saw Blades for Metal Roofing

For rugged metal types like stainless steel or copper roofing, an abrasive chop saw with an abrasive cutoff wheel is often the best option. Here are some things to look for when choosing abrasive blades:

• Material – Aluminum oxide and silicon carbide are common abrasives used in cutoff wheels. Silicon carbide is harder and more suited to stainless steel. Aluminum oxide is a good economical choice for steel.
• Grit – Grit indicates the size of abrasive particles. Lower grit = larger, more aggressive particles. For steel roof panels, 30-50 grit is a good range.
• Disc diameter – 10-14 inch diameters are common for abrasive chop saws designed for metalcutting.
• RPM rating – Make sure your abrasive blade’s max RPM meets or exceeds the no load RPM of your abrasive saw.

When used properly, an abrasive saw will produce clean, accurate cuts through metal roofing with minimal burring. Lubricating the blade and going slowly reduces friction and blade wear.

Band Saw Blades for Metal Roofing

For cutting long straight sections through metal roofing, a metal cutting band saw is extremely efficient. Here are some blade specifications to look for when choosing band saw blades for metal roofing projects:

• Tooth pattern – Look for a variable tooth blade with both raker and gullet teeth to prevent jamming and cut efficiently.
• TPI – For steel roofing, a TPI between 4-14 is ideal. Use fine TPI for aluminum sheets.
• Pitch – Pitch is the distance between adjacent teeth. A pitch between 0.8-2mm gives a good balance of speed and cut quality for roofing.
• Blade width – Common widths are 1/8″ to 1/2″. The wider the blade, the straighter it will cut.
• Bi-metal – Bi-metal band saw blades (tungsten carbide teeth) dramatically outlast conventional steel blades for roofing jobs.

Proper blade tensioning and blade guides are also critical for straight, accurate cuts with a band saw. Using the correct feed rate helps prevent the blade from overheating when cutting thicker metal.

Choosing the Right Number of Teeth

One of the most important blade specifications when cutting metal roof panels is the number of teeth. This determines how coarse or fine the cut will be. Here are some tooth count guidelines based on metal thickness:

Metal Thickness	Recommended Tooth Count
Under 18 gauge (0.0478″)	80+ teeth
16-14 gauge (0.0598-0.0747″)	60-80 teeth
12 gauge (0.1046″)	40-50 teeth
10 gauge (0.1345″)	24-36 teeth
3/16″ – 1/4″ thick	18-24 teeth
Over 1/4″ thick	8-14 teeth

Thinner metal requires more teeth (a finer blade) to avoid deformation while thicker material calls for fewer teeth for faster cutting. Matching the tooth count to the gauge means cleaner cuts and less wear on the blade.

Common Materials Used for Metal Roofing

Understanding the different types of metals used for roofing can help narrow down your blade options. Here are some of the most common metal roofing materials and considerations for cutting them:

Galvanized Steel

Galvanized steel is coated with zinc to provide weather resistance. It is affordable and durable but requires specialty blades due to its abrasiveness. Carbide-tipped circular saw blades work well for galvanized roof panels.

Stainless Steel

Stainless steel contains chromium and nickel for increased corrosion resistance. An abrasive saw with a silicon carbide blade is the best choice for cutting stainless due to its hardness.

Copper

Pure copper roofing provides an attractive look but is difficult to cut due to its softness. For best results, use a silicon carbide abrasive blade and light feed rate to avoid tearing the copper.

Aluminum

Aluminum roofing is lightweight, rustproof, and conductive. Carbide or abrasive blades work well for aluminum due to its softness and tendency to stick to blade teeth.

Cutting Metal Roofing Safely

When working with sheet metal and roofing panels, following some basic safety practices will help avoid accidents:

• Always wear heavy work gloves – Metal edges are extremely sharp after cutting.
• Use eye protection – Sparks and debris can be thrown from the blade during cutting.
• Ear protection – Metal cutting is very noisy, often exceeding 100dB from tools like an abrasive saw.
• Work outside – Cut metal roof panels outdoors to avoid inhaling metal particulate.
• Support heavy panels – Use saw horses or ask a helper to support panels during cutting to prevent slipping and falls.
• Prevent kickback – For circular saws, keep blades sharp and feed rate steady to avoid violent kickback when teeth snag.

Staying alert and using proper safety gear from head to toe will help reduce accidents when using saws to cut metal roofing and panels.

Conclusion

Cutting metal roofing requires the right blade for clean, fast, and safe cuts. For most roofing jobs, a carbide-tipped circular saw blade or a bi-metal reciprocating blade are good options. Jigsaws, band saws, and abrasive chop saws also work well when fitted with the appropriate metal cutting blade. Matching the blade tooth design, gullet size, and TPI to the specific roofing material thickness and hardness results in optimal cutting performance and blade life. Always observing safety protocols like wearing gloves, eye protection and ear protection is critical for accident-free cutting of metal roof panels.