How to Cut Concrete Blocks With a Circular Saw?

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On the road to becoming a master at carpentry and woodworking, one must first learn the basics. Such as, how to cut concrete blocks with circular saw the right way. 

Cutting something so robust can be daunting. It’s easy to end up with pieces of the wrong size, but our experts are here to prevent that in this thorough step-by-step guide.

5 Steps to Cut Concrete Blocks With Circular Saw

Step 1: Strap on your Safety Gear

All excellent craftsman know the importance of safety gear. At heightened temperatures, concrete blocks release silica dust which is harmful to your health.

green circular saw on wooden surface

For this reason, make sure to wear the following: 

Step 2: Mark the Cutting Path Using a Chalk Line

Prep the concrete block you’re about to cut using a chalk line. The chalk line will serve as a guide for your blade and circular saw to follow during the cutting process. 

Step 3: Adjust Your Circular Saw

Set the ripping size or cutting depth of your circular saw to 50mm. Once down, align your blade with the mark you made using the chalk line. 

adjusting circular saw blade depth

Once everything is set, turn on your saw and let it reach max speed or its maximum rate of revolution.

Step 4: Start Cutting Slowly

First things first, you’re job when cutting using a circular saw is to lead your saw and blade, not exert pressure or effort. 

In other words, trust your blade to let it do its thing: cut and rip the concrete block. Simply guide it along the chalk line without exerting extra force or excess pressure. 

Step 4.1 (Optional): Add a Stream of Water to Your Blade

This is an optional step if you’re using a wet blade. If you’re cutting a concrete block with a wet blade, have someone help you add a stream of water to the blade during the cutting process. 

cutting concrete with circular saw

The stream of water added to the blade can help cool the blade and prevent harmful toxins like silica dust [1] from entering your system. 

Step 5: Stop Cutting After 45 Seconds Then Cut Again

The last thing you want is your blade overheating and cutting the concrete block inaccurately. 

During the cutting process, make sure to stop every 45 seconds, then cut again. If you cut continuously without rest, your blade will heat up and produce unfavorable outcomes.

Blades to Use When Cutting Concrete Blocks

You have three options available to you: 

  1. Diamond Blades
  2. Masonry Abrasive Blades
  3. Wet/Dry Cutting Blades
circular saw blade

Diamond blades are the most durable, does not wear out easily, and is more suited to those who frequently perform concrete cutting jobs. 

Masonry abrasive blades are the most affordable and inexpensive but lack the durability and cutting speed diamond blades have. Using masonry abrasive blades means you’ll have to replace it a lot more often than diamond types. 

Wet/dry cutting blades are also diamond blades, making them great choices but the main concern is how hot they become during the cutting process. 

A wet circular blade of a Rotorazer circular saw, for instance, will require you to run a stream of water as mentioned in optional step 4.1 to prevent silica dust from being produced. 

Dry circular blades can expel heat much better but produce higher amounts of silica dust so respiratory masks are a must.

Which Blade Should You Use?

If you’re planning to do a one-time job or a quick woodworking session, it’s recommended to use masonry abrasive blades.

diamond blade cutting through tile

If you have regular concrete jobs, diamond blades work best. 

We only recommend using wet cutting blades if you have a specific circular saw that has special parts to add water stream during the process.

When Is the Best Time to Cut Concrete?

This depends on the weather conditions, timing, concrete mix, and hardness. Cutting concrete too early causes raveling and cutting too late will cause uncontrolled cracking. 

operating a circular saw

As a general standard, in hot weather conditions, it’s safe to cut concrete at least four hours after pouring the concrete and 12 hours after in cool weather conditions.

It’s important to take note of this since cutting concrete blocks in the wrong time can lead to abrasion and wear and tear. Furthermore, avoid the following: 

  1. Using the wrong blade
  2. Pushing or exerting too much pressure
  3. Using a circular saw with a ben spindle
  4. Cutting at high speeds continuously 
For powerful circular saws, you can check our list of top-performing corded circular saw here

How Deep Should the Cuts Be?

The general rule of thumb to follow is 1/3 to ¼ of the slab’s thickness. So if you’re cutting an 4-inch concrete block, then about 1.3 to 2 inches deep. 

Now what to do about the remaining 2 inches? You can use a jackhammer to finish up the job. 

sawing concrete

The general rule of thumb to follow is 1/3 to ¼ of the slab’s thickness. So if you’re cutting an 4-inch concrete block, then about 1.3 to 2 inches deep. 

Now what to do about the remaining 2 inches? You can use a jackhammer to finish up the job. 

Other sources you can read: 


Now you know how to cut concrete blocks with a circular saw. With all the information you now have at hand, cutting concrete blocks doesn’t seem to be as daunting now, does it? If you have plans to try this at home, try watching a demonstration materials first for safety purposes like this one here.

If you are confused about when to use a circular saw or a miter saw, here is how we pitted circular and miter saw.

More helpful guides to check: 

Learning how to cut pavers 

Robert Johnson is a woodworker who takes joy in sharing his passion for creating to the rest of the world. His brainchild, Sawinery, allowed him to do so as well as connect with other craftsmen. He has since built an enviable workshop for himself and an equally impressive online accomplishment: an extensive resource site serving old timers and novices alike.
Robert Johnson
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