Few things protect your home better than a metal roof. Ice and branches tend to slide right off, and when properly installed, they can last anywhere from 40 to 70 years. On the other hand, an asphalt roof rarely lasts more than 15 years. At worst, the roof is dented by large hail rather than having holes punched through it. However, the same factors that make your metal roof so strong make it difficult to modify. If you need to know how to cut steel roofing, here are several ways it can be done.
Use Tin Snips and/or Metal Shears
You should use tin snips when you’re going to cut or trim a single piece of metal roofing, though you could also use aviation snips. Tin snips are another name for tinner snips or metal shears. These are hand tools used to cut sheet metal.
Unlike standard scissors, they generally have a compound leverage handle system. This makes it easier to cut through the metal. While you get stronger cutting action, you still get precise control. One of the side benefits of using sheet metal shears is that you don’t produce metal shavings or sparks as you’re working. However, you should still wear protective gloves and goggles when cutting metal pieces with tin snips.
You’ll need to get the right type of tin snips for the cutting you’re about to do. Yellow or plain tip tin snips are best for cutting straight lines. Red handled left-handed snips are the better choice when you want to remove metal to your left. They will, by definition, be held in your left hand. Right-handed snips have green handles. These are ideal for cutting in a clockwise motion, while the waste comes off the right side.
Power shears are similar to tin snips except they do most of the work for you. They come in both pneumatic and electric varieties. They’re suitable for quick, straight cuts.
First, draw the path you’re going to follow before you start cutting. Mark the straight lines and curves you’re going to cut off the metal piece. Mark any holes you’re going to drill or cut into the metal as well.
If you’re not cutting end to end across the sheet, cut out a pilot hole. This can be done by drilling with a metal-cutting drill bit or hammering a nail through the metal. Only cut the pilot hole on part of the metal you’re going to remove so that you don’t end up with a jagged edge.
Open up the snips. Line up the blade with the line you’ve marked, then start cutting. One of the benefits of working with tin snips is that you can double-check and adjust where the scissor blades are located before you cut. If in doubt, double-check before you press down on the shears.
Press the jaws down as firmly as you can, so that you get as much metal as possible with each bite. Then open the jaw as widely as you can before repeating the process. If you’re working with power shears, then you’ll press the trigger and direct the blade as you move along the metal.
Work slowly so that you maintain control. Keep the jaws of the snip pressed against the jaws of the tin snip. If the blades get stuck, you’ll need to approach the cut from the opposite angle.
Break Out the Circular Saw
A circular saw, also called a nibbler, is the best choice for cutting large pieces of metal roofing. We recommend cutting through individual pieces of metal roofing rather than trying to cut through several pieces stacked together.
Also, wear proper safety gear – this includes earplugs and safety goggles. You may want to wear a face mask since a saw will generate metal dust and even flying metal fragments.
The first step to cutting metal roofing with a nibbler is to set up the saw. The circular saw should have a metal-cutting blade. You could use either a carbide tooth blade or a steel tooth blade. Set the blade so that it will cut through the lowest parts of the corrugated metal.
Mark the path you’re going to follow while cutting. Attach the metal itself to the work surface, because you might fail to follow your intended path if the sheet shifts.
Now you can begin cutting. Note that saw blades can get hot, so make sure you stop and inspect your work, and give the blades time to cool down. This reduces the risk of damage to the metal roofing.
If you want to create rounded cuts to finish the workpiece, use an electric drill nibbler, or use the nibbler to cut vent pipe holes.
Use an Angle Grinder
An angle grinder is an alternative to the circular saw. It is handheld, so it is more mobile. The downside is that it requires more hand control. Angle grinders are designed for abrasive cuts and polishing. They should be used for straight cuts on metal roofing, though you can also use them to smooth out the burrs on metal pieces you cut with other tools.
The angle grinder needs a blade capable of cutting through metal. This could be a carbide tooth blade or a steel tooth blade. The benefit of carbide is that it lasts longer.
Draw the line you’re going to follow when cutting. Then mount or attach the metal sheet to the work surface so it doesn’t move while you’re working.
You may need to cut out pilot holes with a metal drill bit or by hammering a nail through the metal. This isn’t necessary if you’re going to cut the metal end to end.
Line up the blade with your cutting path. Then begin cutting. Cut slowly, so that you have complete control of the tool. Always keep your hands on the saw’s guard.
If the angle grinder stops working, turn it off and pull back. Do not try to force it forward. Let things cool off, if necessary, and then complete the cut from the opposite side.
Whether you want to trim rust off your sheet metal roofing or need to cut a vent hole into the existing metal panels, know how to cut steel roofing panels before you being work. You can’t afford to risk being injured or having to replace large panels because you made a mistake while cutting the metal.