How to Cut Concrete Blocks With a Circular Saw

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Whether you’re building a patio or making yourself a nice fire pit, you will find yourself needing to cut concrete blocks at some point in the process. The good news is, you don’t need a concrete block cutter to get the job done.

Here’s a guide on how to cut concrete blocks with a circular saw.

How to Cut Concrete Blocks With a Circular Saw

Besides the saw and a blade, you may need a hammer and chisel for this.

Step #1: Wear Protective Gear

Circular saws are advertised as an easier-to-use alternative to table saws. While the saw may be easy to use, it is also very dangerous to handle. The outer edge of the blade spins at speeds of 120 mph, and slip-ups can cause serious injuries.

A study by the Atlantic Charter Insurance Company revealed that circular saw mishaps lead to 10,600 ER visits every year. In some cases, accidents with circular saws have proved fatal.

To protect yourself when working with a circular saw:

Person holding a circular saw
  • Put on safety glasses. You could pair the glasses with a face shield for more protection.
  • Wear a dust mask to protect yourself from the silica dust generated during cutting.
  • Use ear protection to ensure the noise doesn’t affect you.
  • Keep the area clear of wires and ensure the circular saw is in proper working order.

If you’ve never used a circular saw before, getting a friend who has experience or hiring a professional to help is a good idea. Not knowing how to use a circular saw increases the risk of kickback, which can lead to severe injury.

Step #2: Mark the Cutting Path

After ensuring that the saw is working correctly and wearing the recommended protective equipment, you must mark the cutting path you need to follow all around the block.

Most prefer using chalk to do this, but you could use caulk to mark the path if you don’t have any chalk.

We recommend using a ruler or measurement tape to ensure that the lines you draw are straight. Not only will marking a perfectly straight path make working with the saw easier, but it will also ensure that the final result looks neat.

Step #3: Set Up Your Saw

Using the right kind of blade and going through the blade attachment process properly is critical to making your cutting experience smooth and safe.

There are three kinds of blades you could set up with your saw:

  • A masonry blade: An inexpensive blade that is great for cutting a few concrete blocks. Cutting speed and durability are low, so if you will be cutting dozens of concrete blocks, this isn’t the right blade to set up with your saw.
  • A dry diamond blade: Dry diamond blades are expensive but last a lot longer and cut a lot faster than masonry blades. These blades are made out of a sturdy composite, and if you’ll be cutting a lot of concrete blocks, this is the right blade to buy and set up with your saw.
  • A wet diamond blade: Similar to a dry diamond blade, a wet diamond blade is made from a sturdy metal composite. However, you will need to have a steady stream of water flowing through to the blade when cutting. The water will reduce the heat generated by the blade and will also prevent silica dust from forming. Like its dry counterpart, the blade is expensive but certainly worth the price if you have a lot of concrete blocks to cut.

How To Install A Blade On A Circular Saw

The installation process varies slightly from saw to saw. However, in general, you must first remove the bolts and the washer from the saw and slip the blade into the saw.

You must then put the washer and bolts back and use a screwdriver to ensure they’re secured tightly.

Referring to the user’s manual before installing any blade on your saw is a good idea.

Step #4: Adjust Saw Depth

Your circular saw isn’t ready to cut concrete blocks just yet. Adjusting the saw depth essential to ensure safety and efficiency when cutting concrete.

Concrete blocks

To adjust saw depth, you must pull the knob on the side of the saw to unlock the depth tilting base. After you’ve adjusted the saw depth, you must reset the knob’s position to lock the depth tilting base in place.

We recommend that you set your saw’s depth at ¼” and cut concrete blocks since it reduces the risk of binding and circular saw kickback. However, if you have exceptionally thick blocks at hand, you can set a larger saw depth.

Step #5: Start Cutting

Don’t start cutting right after you turn the saw on. Let the saw reach its maximum RPM. Then, align your circular saw along the cutting line you marked.

When the blade’s spinning as fast as it can, begin cutting the concrete block along the marked line. Make sure you take it slow and let the saw do the work.

If you’re using a wet diamond blade, you will need someone to help maintain a slow stream of water during the cutting process.

Once you cut through one side of the block, flip it over to the other side, and begin cutting again.

Warning

Do not keep your saw working for more than 45 seconds at a time to prevent it from overheating.

Step #6: Part the Concrete Block

After you’ve cut all around the concrete block, the final step is to part the block into two.

All you have to do is place your chisel in the gap you’ve created by cutting and give it a tap with a hammer. This will cause the concrete block to split clean open.

Make sure you don’t hit the chisel too hard since this can cause the concrete block to break unevenly. If your concrete block is smaller in size, a gentle tap on the floor will also do the trick.

Here’s a concise video that illustrates the entire cutting process wonderfully.

Conclusion

Cutting concrete blocks can be easy as long as you’re using your tools right. Now that you’ve gone over this guide, you will be able to cut concrete blocks without breaking a sweat.

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.