Cement board is made of cement reinforced with fibers, to make a strong, durable board. It is used in construction, as a stronger, more durable, and quicker-drying product than drywall. Cement board is also an excellent backing board for tile. With cement board, tiles do not need a thick bed of mortar, and can be laid in thin-set instead, simplifying installation.
Because cement board can be used in interior and exterior walls and subfloors, and in wet as well as dry applications, it makes home construction, repairs, and improvements simpler to execute and more durable.
However, cement board is heavier to work with and more difficult to cut than drywall. Here are the best ways to cut cement board.
Before Cutting Cement Board
The most important thing to remember is that cutting cement board produces a crystalline silica dust that is hazardous to inhale. When cutting cement board, use eye protection and a dual-cartridge respirator. Make your cuts outdoors, and far away from any open doors, windows, or air intake vents. It’s also a good idea to use a sponge to wet your cement board before cutting in order to control dust.
Score and Snap Method to Cut Cement Board
Like cutting drywall, you can score and snap cement board. You will need a carbide-tipped scoring tool that is hard enough to score cement board.
Like cutting drywall, you measure and mark your cut with a carpenter’s pencil. Using a straightedge, draw the cutting tool along the line, scoring the surface of the cement board. Repeat this a few times to score a deep groove in the board. Press on the back of the board at the cut line (or fold it over the edge of a workbench) to snap the board where it has been scored.
Use the cutting tool again to slice through the fiberglass mesh and separate the board at the cut. This will create a rough edge at the cut, but it can be smoothed with a rasp. This method produces very little dust when compared to using power tools, but is most effective with ¼ inch cement board and not thicker.
Using a Circular Saw to Cut Cement Board
With the right power tools, you can also cut cement board like you would wood. If you have a circular saw with a carbide-tipped wood-cutting blade, you can use it to cut cement board.
Using a circular saw with a blade that has a low number of carbide-tipped teeth (the fewer teeth on the blade, the less dust is created and the easier it is to cut cement board), you can cut cement board the same way you would cut plywood or MDF. This method produces a lot of dust.
Using a Jigsaw to Cut Cement Board
Just like with a circular saw, you can cut cement board with a jigsaw, provided you have a very coarse metal-cutting or carbide blade. With a jigsaw, you can cut straight lines as well as curves. This method is effective, and less dusty than some, but is also slow and will quickly wear down blades.
Using a Dedicated Cement Board Cutting Tool
There are power tools that are specially designed for cutting cement board. They usually take the form of power shears, although some have large arms and operate more like tile cutters. Specialized tools cut cement board extremely fast and efficiently, with very little dust. Because they are specialized tools for cement board, they work very well, but many amateurs may not be cutting enough cement board to make it worth investing in a single-purpose power tool.
While it is possible to use other power tools that abrade rather than cut, like angle grinders, to cut cement board, it is the least effective and most dusty method, and is not recommended by experts.
Cement board is a great material that has a lot of advantages for home repair, home improvement, and construction projects. However, most people who want to use this amazing material find it necessary to adopt new tools and methods for working effectively with it, because it is tough and heavy, and often has a rougher surface than the gypsum drywall many people are familiar with. With only minor modifications, you can use your existing power tools to cut cement board, but look for coarse blades with few teeth and carbide tips for the best results.
If you have a big project ahead, consider investing in a specialized tool just for cutting cement board; it may be worth investing in a dedicated tool if it saves you time, money on blades, and makes the work site safer. Remember to always protect yourself and others from inhaling the dust created when cutting cement board, and use the best method for your job site.