Learning to cut concrete can seem like an intimidating process if you’re a DIYer, but don’t fret, cuts less than 6” deep are more than doable with a little knowledge and some basic tools.
There are numerous reasons you might need to cut into concrete, including to repair cracks in concrete, creating control joints in a freshly cured slab, or if you’re building a custom concrete project like a planter or table.
If you’re cut is less than 2 1/4” deep, then you likely already have most of the required tools lying around the garage or toolshed.
Let’s take a look at the best methods to cut into concrete, including how to get the job done safely and with minimal risk.
Tools & Materials
The exact tools needed will vary somewhat from one job to another, but the main thing to remember is that if your cut is less than 2 ¼” deep you’ll be able to use a standard circular saw. Deeper cuts will require a special walk behind concrete cutting saw, which can cut 17”+ in the case of larger models
- Circular saw
- Walk behind concrete saw (for deeper and larger cuts)
- Dry or wet-cutting diamond blade
- Shop vacuum
- N95 breathing mask with face shield
- Chalk line or spray paint
- Cold chisel and sledgehammer
- Drop cloths
Cutting Concrete – Step-by-step Guide
Step 1: Choose Your Cutting Tool
If you only need to make a small cut in concrete you can do a decent job with just a small sledgehammer and cold chisel. This is not the most accurate or efficient method though, and only really works well for smaller jobs.
If you’re cutting task is a little more complex, then you’ll likely want to step up to using a circular saw. A circular saw combined with a decent diamond cutting blade will do a surprisingly good job of making cuts in concrete.
The only real issue with using a circular saw – besides your depth being limited to 2 ¼” for a standard 7 ¼” saw – is that you’ll need to come up with your own dust collection system. Concrete dust is a serious health hazard, and too much exposure can cause silicosis, an incurable respiratory condition.
Some circular saws come with a port for attaching a shop vac too, which will be helpful in keeping the level of dust down. Other things you can do are use a hose to create a small stream of water in front of the saw or have someone hold the shop vac next to the saw to collect dust as it comes out. If you’re going to go with the hose method, you’ll want to go with a wet-cutting diamond blade – as these are built for cutting in wet conditions.
If you’re going with a wet-cutting saw, then keep in mind the water will also work to lubricate the blade as well as keep the dust down. You can also use water when cutting with a dry-cutting blade, but it isn’t necessary.
And if your cutting job is going to require particularly deep cuts, then renting a walk-behind concrete saw makes sense. These saws are purpose-built for making cuts in concrete, feature deeper cutting depths, and integrated water systems, and are self-propelled so their easy to use.
Renting a gas-powered saw is another good option if you need to make a large volume of deep cuts.
Step 2: Safety Prep
As mentioned previously, cutting into concrete creates a lot of harmful concrete dust. Before you start cutting anything, make sure to properly prepare the area as well as have the necessary safety gear on hand.
As far as preparing the surrounding area, make sure to block off the work area from the rest of the building. Use drop cloths or plastic sheeting to seal off any windows or doorways, as well as cover any ventilation nearby.
You’ll also want to make sure you use a GFCI (Ground Fault Circuit Interrupter) extension cord for your electric saw. These cords are designed to prevent electric current leaking, as well as prevent electrocution, burns, and shocks.
For your own personal safety, the most important thing to do is to make sure you have proper breathing protection. Ideally a full-face shield with an integrated N95 respirator. A half-mask respirator and a good pair of safety goggles will also work.
In addition, you’ll want to wear steel-toe boots, ear protection, and knee pads, but the most important thing is the respirator and eye protection.
Also, make sure anyone assisting you has the same level of safety gear.
Step 3: Mark the Cut
Cutting into concrete is a little trickier than cutting into wood and other softer materials. It’s more difficult to correct a cut once you start to veer off, so you’ll want to do a good job measuring and marking out the cut before you get started.A chalk line is a useful way to mark out the cut, but you can also use marking spray paint or even score a line in the concrete using a sharp chisel.
Step 4: Start the Cut
If you’re cutting on the floor, then the dust collection will be easier than if you’re cutting into a vertical surface like a wall.
Start the cut by making a slow plunge cut into the concrete. Once your blade has reached its proper depth, slowly push the saw forward along the line you created in the previous step. If you don’t have an integrated dust collection system, then have your assistant hold the shop vac near your saw’s dust port or trickle water in front of the saw to keep the surface wet.
Be very careful when guiding the saw not to veer off course. I’ve made this mistake before and it results in a poor-looking final result as you’ll need to reposition the saw and make another plunge cut.
Step 5: Utilize a Guide Board to Complete the Cut
A guide board can be helpful for making a straight cut. A guide board is simply a straight 1” deep piece of scrap wood as long as the cut line that you run your saw along.
Depending on the depth of the cut that you need, you may need to remove the guide board after the first pass and continue with a second pass without the board to deepen the cut. After the first pass, the saw blade will be guided by the first channel, so you won’t need the guide board to keep your cut straight.
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