Cut Cinder Blocks Efficiently With A Tool You Might Already Have Sitting In Your Shed

When you see professionals cutting through cinder blocks, chances are good that they'll be using either a heavy-duty 9-inch angle grinder or a powerful disc cutter. Neither of these are likely to be a tool you have in your shed, but a circular saw might be. With the correct blade and appropriate technique, it is possible to use one for cutting cinder blocks at home, so you can build walls or make cool patio furniture.

A circular saw is high on the list of must-have power tools for first-time homeowners. It has a wide variety of uses around the house and yard and is invariably supplied with a blade for cutting wood. However, in order to cut through cinder blocks, you'll need to do a few things: First, swap the original blade out for a diamond blade. Professional equipment may use wet cutting to help cool the blade, but for a standard circular saw you need a segmented blade that is used for dry cutting. Be sure to order the correct diameter for your saw, which will usually be either 6-½ inches or 7-¼ inches. You'll also want a dust mask and some goggles. Cutting cinder blocks produces a lot of dust, so it's a good idea to work outdoors whenever possible.

Before you start, make sure you know how to use a circular saw safely. The principles are the same regardless of what material you are working with. Let's start with the relatively easy first step: Cutting through the thinner sides, or ends, of a cinder block, if you need to remove a chunk. To start, mark the cut line with a Sharpie or a piece of chalk. Then, with the saw unplugged or the battery disconnected, set the depth of cut to roughly half the cinder block's thickness. Connect the power, rest the front of the saw on the cinder block, and make the cut. Then take a second cut at the full depth. It is easier on the saw to take shallow cuts than to go for it all in one. Don't force the tool — just apply gentle pressure while it cuts.

A slightly different approach is needed if you want to cut the cinder block in half through the thicker central web. 7-¼ inch circular saws have a maximum depth of cut of around 2-½ inches, which is nowhere near enough to go all the way through. Instead, take a cut of about an inch all the way around, then go to the full depth of 2-½ inches that the saw is capable of and go around again. Finally, put a masonry chisel in the gap and strike it with a hammer. By this point, the cinder block will be weakened, so it should break through the remainder fairly easily.