How to Cut Hardie Board

When it comes to installing hardie board, overall it is fairly simple. It is however a bit labor intensive. I recommend having at least one person help you in your installation of hardie board. James Hardie board is a bit on the heavy side, so use your legs and not your back!

The biggest issue with the installation process of hardy board, seems to be the process of actually cutting the hardy board. I get asked what the best way to cut hardy board is all the time. I am going to break it down in to my top pick of the easiest, fastest, and cleanest methods of cutting hardy board. These hardie tools listed below will cut all variations of James Hardie Board, including hardibacker, hardie board siding, hardie plank, and any other kind of cement board or hardie panel. Some of the methods however, do not work well when attempting to cut dura rock as it is made up differently from James Hardie siding plank products.

  • Hardie Board Shears
  • Circular Saw with Hardie Blade
  • 4″ Angle Grinder with Diamond Blade
  • Jig Saw
  • Utility Knife

Starting with the first on the list, Hardie Board Shears. These shears are number one on my list for a big reason. They are lightweight, compact, easy to use, and virtually dustless. One of the major manufacturers of Hardie Board shears, is Hilti. You can pick up these shears at your local hardware store such as, Home Depot. and Lowes. Hardie Shears do have a draw back however, they tend to crush, crumble, and break the edges of the hardie board if you get too close to the edges. Hardi shears are expensive, and if you are looking to buy instead of rent, I suggest waiting for a sale to find them on discount, or even shopping online.

If you have basic power tools, chances are you will have a circular saw. You can use a circular saw and a traditional blade to cut hardi board. However, a tradition blade in a circular saw will produce a massive amount of dust. Unless you have a dust collector, the amount of hardie board dust created is almost unbearable. For this reason, you can now buy hardie blades specifically designed to cut down on the amount of dust produced while cutting hardi board.

Another very conventional way to cut hardy board, is to use a 4″ angle grinder equipped with a 4″ diamond blade. A diamond blade will easily cut through hardy board, and is great for making small intricate cuts, that you would normally have to make around windows, and door trim. The draw back to a 4″ angle grinder and a diamond blade to hardi board is similar to most other disadvantages, It creates a whole lot of dust. Once again, the dust is almost unbearable, so investing in a cyclone dust collector may not be a bad idea!! You must also be careful when using a grinder to cut hardi board, that it does not kick back on you possibly cutting you.

Using a jigsaw for cutting hardie board, is not my first recommendation when attempting to make long cuts. If you are making cuts that zig and zag, are very tight, or even circular, a jigsaw is definitely the way to go. The hardie board will eat through the blades quickly though, so make sure to change them often.

The last way that I would recommend cutting hardie board, is with a utility knife and a straight edge. This is the cheapest tool that you can buy to cut hardie, and really is still pretty simple and fast. The cuts will have to be straight for the most part for a utility knife to work effectively. Simlpy draw your line, score it a couple times with the knife, and break. This method works better on the 1/4″ hardie board but will still work with the 1/2″ hardie board.

It is a good idea to always take the proper safety measures when dealing with installing hardie board. Remember to always cut in a well ventilated area or outside, and always wear the appropriate protective gear. Such as safety goggles, ear plugs, and gloves. If you have found a more effective way of cutting hardie board, feel free to leave a comment explaining how you prefer to do it.

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