How to cut metal roofing [Corrugated and sheet metal]

If you need to know how to cut corrugated metal, first learn the different sheet metal cutting tools so you can pick the best tool.

It also helps to order corrugated roofing the right size so there is less cutting to do, however, you still need a metal cutting tool to cut the angles, curves, and lengths that couldn’t be made to order.

Also, make sure you have the right roofing material for durability considering the wind and rust protection. If you are close to the ocean you need more protection.

Read on to find out what roofing metal to pick and the best tool to cut sheet metal roofing.

1. Cutting metal roofing with a nibbler

A nibbler is the best way to cut metal roofing, a nibbler, unlike electric shares, a nibbler can be moved more easily to cut around corners quickly and easily without jamming.

An electric nibbler is what a professional roofer would use, it punches its way through the metal in a fast and tidy way to leave a clean-cut.  Nibblers cut metal roofing materials like butter.

Nibblers work great because they cut a decent amount of metal out with each punch so that the blade doesn’t jamb as shears and tin-snips can.

There are actually 4 different variations of a  nibbler tool.   But a Makita nibbler is the most popular.

Tip:

It is recommended to cut visible roofing edges half an inch longer and then tidy things up with a second cut with a good pair of tin-snips at the end.

Pros:

• Smooth and consistent cutting.
• Excellent for cutting around corners, or corrugated metal sheets on an angle as the cutter has to go up and down over each corrugate, the nibbler is good at this. Whereas shears or tin snips would slow and messy.
• The cut is clean and tidy and generally without sharp edges, that other tools can leave.

Cons:

• For cutting straight unseen edges, electric shears could be faster.
• Most expensive tool option for cutting metal roofing.

2. Cut metal roofing with electric shears

Electric metal shears, come in two varieties, a standard plug-in in power-tool, or better an attachment for your impact driver, this is best done with malco tools. Shears are a cheap tool that can quickly cut sheets of corrugated metal in straight lines with little effort.

Pros:

• Cheaper than a nibbler.
• Can cut straight lines fast than using tin snips by hand.
• Perfect for quickly cutting metal roofing, that is hidden under a ridge or flashing.
• Faster than a nibbler for straight cuts.

Cons:

• It cannot cut around corners or cut angles well.
• Joust like tin snips they cannot cut along the same direction as the corrugate, only cross-cutting the metal sheet.
• The tool has less working life than a nibbler.
• Hard to use for anything but a straight cut.
• The sheet is ideally laid down on the ground when cutting.

3. Cut metal roofing with an angle grinder

Using an  electric angle grinder or a cordless grinder isn’t the recommended way to cut metal roofing. Metal roofing is thin enough for much safer and faster tools to do the job. Grinders can leave behind sparks that can burn the paint finish, and also leave a dangerous sharp cut edge.

Pros:

• If you use a diamond wheel instead of a steel-cut-of disk, the blade won’t wear out. But changing blades all the time inst a problem with shears or nibblers anyway.
• If you are cutting thick corrugate, like hole or cut, out of a steel shipping container, then an angle grinder is the best choice – use a steel cut-off blade.

Cons:

• Steel-cut of blades can wear-out fast.
• Leaves a dangerously sharp edge that should be taken of with a file.
• Sparks can burn and damage the paint finish.
• So not recommended metal roof cutting tools.

4. Cut metal roofing with tin snips

The cheapest way to cut metal roofing is with a pair of tin-snips. You want a pair of straight cuts, or left or right-handed pair, for cutting both straight, and around corners.

The best tin snips are good for cutting any edge of corrugated iron that is going to be seen, as they are easy to control when cutting. It is the most common way to cut galvanized, stainless steel, and plastic flashing’s.

Although there are faster tools for bigger jobs like using an impact driver or drill attachment electric shears or a nibbler drill attachment.

You can generally get away with only 2 pairs, as most of the time you only need to cut around a corner from one side left or right. You can turn a pair of corner cuts upside down to make a cut in the other direction if you want. It is however sometimes better value just to get a set of three so you have a replacement pair as well.

When using tin snips to cut thick metal, or if you are using low-quality metal snips, they might fail with the two blades starting to separate causing the snips to not cut as effectively. 

Metal corrugated roofing can come in different gauges, most gauges can be cut with tin-snips easily, but slowly. And for this reason, there are other tools for cutting metal roofing such as metal shears or an  electric nibbler.

Pros:

• Clean controlled cut.
• Cheap tool.
• Reasonably easy to cut a big sheet up as long as both sides are biggish.
• The best tool to tidy up seen metal roofing areas, for example, you cut the seen visible roof edge quickly with a nibbler, while you cut first with the nibbler half an inch longer than needed. After the roofing has been installed you later trim the last bit of corrugated metal roofing in a tidy way with a good pair of tin-snips.
• You can cut big sheets of metal roofing in half as long as the off-cut is big enough to hold and twist out-of-the-way to let the snips keep cutting.

Cons:

• If you are cutting more than .75 Inch off, it is difficult to cut corrugated iron with tin snips. Unless the of cut is big enough, to hold onto and bend out-of-the-way.
• Very slow.
• You can’t cut along the sheet, only effective cutting is cross-cutting the corrugated iron.

Tip; Make sure to order roofing the right size

Before you know how to cut metal roofing; order and let your supplier know what lengths are actually wanted.

Basically, order the sheets at the length that you need. This will eliminate wastage and reduce the amount of cutting that would need to do.

Sometimes you are going to have to cut corrugated roofing yourself if you are recycling roofing material. Or if you have a roof angle that a factory won’t cut for you. Or when working around roof penetrations.

Get the right roofing thickness and gauge

Corrugated roofing comes in different gauges, the thinnest gauge is easier to cut with tin snips, but if someone walks on your roof it can dent easily. Corrugated roofing that has a thicker gauge isn’t that much more expensive, and worth it in my opinion. But requires a nibbler to cut, the thicker gauge.

With a stronger thicker gauge roofing iron you don’t have to worry so much about your getting dents if someone walks on the roof for maintenance. A nibbler will easily cut all gauges of roofing but like I said above tin snips really struggle on thicker gauges compared to a  nibbler.

Make sure that the tools to cut metal you use are compatible with the thickness of your roofing material, nibbler tools pack plenty of grunt for thicker metals.

Metal roofing types and expected rust protection 

1. Galvanized Steel Roof – Surface layer protection only, and corrodes on cut edges.
2. Zincalume OR Galvalume Roof – Both basically the same thing, standard, and good lasting protection in general settings.
3. Aluminum Roof – Long lasting around the sea but the roof expands a lot with the change of temperature, this can sometimes break fixings.
4. Zinc Roof – Very high life, around the sea, but scratches easily.
5. Copper Roof – Extreme long life around the sea. But any steel metal shaving left on the roof well rust through a hole. Copper roofs are bad for the marine environment when water run-off makes its way to the sea via stormwater pipes.

Galvanized steel roofing.

A galvanized steel roof has a zinc coating layer of protection only, the cut edges, therefore, are not protected around the sea. These roofs will quickly rust from the cut join-up. This is especially true around the sea. Known as the “sea spray” area.

Zincalume and galvalume roofing.

Zincalume and galvalume roofing are much the same except licensed in different country’s. They are a mix of aluminum and zinc through-out rather than just a zinc coating. This gives cut edges some protection against rusting.

A Galvalume roof is available corrugated, with many design types.

Aluminum roofing.

It lasts a long time while being cheaper than getting a zinc or copper roof installed. Although as mentioned above, it can expand and shrink a lot with heat.

Zinc roofing.

A zinc roof costs more but has a very good life in areas close to the sea this means your roof can last a lot longer.

A zinc roof is generally installed with a series of trays and a cap.

Copper roofing.

A copper roof is the most expensive material to build a roof out of. Copper is extremely long-lasting even around the sea. It also looks very nice.

Although a copper roof will turn green after it ages for a few years, it is also bad for the marine environment, when the water run-off ends up in the sea via stormwater pipes.

Conclusion

When working out how to cut metal roofing you need to know what tools you need for straight cuts and corner cuts.

Fast straight cuts, electric metal shears are affordable and work well. For cutting angles and curves you need to use a nibbler tool.

And for tidying up your cuts make sure to have the best tool to cut metal.

Most roofers take advantage, of a good nibble