The Meticulous Task of Concrete Sawing

Concrete sawing is a highly technical practice, which requires the expertise of a specialized company. Across Canada, numerous companies offer a wide range of services to the public, including concrete sawing, drilling, or demolition. 

In this article, we’ll detail the tools used for concrete sawing so you can better understand how a company can carry out such work, both indoors and outdoors. We’ll also give you a few pointers to follow if you’re considering putting expansion joints in your concrete patio, terrace, or concrete opening. 

Concrete Sawing: Why and How?

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The purpose of cutting concrete is to create openings in two types of structures:

• Concrete walls;

• Concrete floors.

As such, concrete sawing enables you to cut out window openings in walls or cavities in floors. 

What are the different methods used?

There are 3 types of saws used for sawing concrete:

• Floor saw; 

• Wall saw; 

• Wire saw.

Avoid mistaking wall and floor sawing for simple term distinction between cutting a floor or wall. They’re actually two very different sawing techniques, to which a third is added: wire sawing. 

What do these three concrete sawing methods have in common? The use of a diamond blade to cut concrete and a need for a constant water supply, which allows for the following:

• Cooling down the tool;

• Reducing dust.

What equipment is used for sawing concrete?

The equipment needed directly depends on the type of sawing. Therefore, we can account for three, one for each type of sawing.

1- Floor sawing

The floor saw is a walk-behind machine that, on one side has a circular saw, which is used to cut a concrete floor. 

It’s used to: 

• Install gutters;

• Cut holes;

• Add expansion joints;

• Cut sole plates;

• Groove surfaces. 

There are fuel-floor saws and electric walk-behind floor saws. Both are used in interior, non-ventilated spaces, as well as on worksites needing reduced noise pollution.

2- Wall sawing

Even 80 cm of concrete can’t withstand this circular saw. Whether cutting vertically, horizontally, or at an angle, this wall saw can practically do it all:

• Cut beams;

• Saw posts;

• Create door openings;

• Make window holes;

• Cut a staircase hatch.

This precision tool is mounted to a track, which is securely fastened to the frame.

3- Wire sawing

Here’s what you need to cut concrete with a wire: Guiding pulleys or wheels, a steel wire embedded with diamond beads, a water supply system to dampen the wire, and a wire tensioning system.

While setting up all this equipment might seem tedious, note that wire sawing is highly useful. In fact, the wire can access very tight and narrow areas that other sawing methods can’t reach.

And there’s more: Wire sawing really doesn’t have a cutting depth limitation since it can be used to saw several metres, both vertically and horizontally. That’s why it can be used to saw:

• Bridge piers; 

• Piles;

• Walls.

If ever you’re looking for a method of cutting that’s even quieter than the electric walk-behind saw, there you have it. Wire sawing is the most discreet of the three methods above described. 

Examples of Services Provided by a Concrete Sawing Company

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To cut concrete, you have to hire a company that specializes in concrete sawing. The reasons why are as follows: the material is substantial, expensive (thousands of dollars worth), and requires an expert hand. We’ll touch on this matter later on. 

Right off the bat, let’s say that with this equipment, you can carry out numerous tasks, and the companies offset the costs by providing the general public with the following services:

• Sawing door and window openings;

• Converting multi-storey parking buildings and commercial spaces;

• Sawing a porch or to fit a gutter;

• Electric sawing interior and exterior work;

• Cutting asphalt; 

• Opening slabs and sole plates;

• Sawing expansion joints.

To these services specific to a concrete sawing company, one can also add the following:

• Concrete drilling (wiring, ventilation ducts, etc.);

• Demolition;

• Polishing;

• Formwork;

• Excavation;

• Concreting (forming and pouring concrete);

• Concrete injections.

By concrete injections, we mean injecting epoxy, a resin-based filler that closes cracks that have formed in the concrete structure.  

Concrete Sawing: FAQ

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How thick a piece of concrete can you cut?

It all depends on the professional in question and the tools used. Some companies can saw 48-inch thick walls (121.92 cm), while others will use wire saws and basically have no limitations. 

Therefore, determine your needs to choose the right company to carry out the work. 

Can I cut concrete myself? 

If you have the right materials to carry out such work yourself, follow the tips detailed below to start off on the right foot: 

• Cut in a straight line;

• Cut at least 2 inches deep;

• At most, avoid cutting a coating that’s thicker than 12 inches;

• Maintain a clean surface by removing any dirt after each cut;

• Plan for a storage area to store the waste prior to disposing of it in a purpose-designed location.

How do you cut a concrete slab to add expansion joints?

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Cutting a concrete slab or wall post-curing is one of the methods used in the construction industry to add expansion joints. 

To do it yourself, you’ll need a floor saw, measuring tape, something to mark the concrete with, and a garden hose.

Once you’ve cut a groove with a floor saw, remember to spray the area with a garden hose to remove any dust that’s stuck to the surface. And there you have it, an expansion joint.  

How far apart should two concrete slab expansion joints be?

Specific to the province of Quebec, the rules associated with making a concrete slab state the following: 

• The maximum distance between 2 expansion joints is 13.12 sq. ft. (4.5 m);

• Square-shaped slabs or with a length/width less than 1.5;

• A groove that’s at least ¼ inch as thick as the slab;

• Avoid T-shaped intersections; these often crack the slab;

• Install control joints on the inside corners.

How to cut a window or door opening in concrete?

Get a wall saw, a generator if need be, and a compressor to spray water on the diamond saw blade.

Outline the shape of the door or window on the wall. For a door, add a cut line in the middle and across the shape, then set the saw on the ground to start at the base.

Once the base has been cut, you can move on to its frame. The trick here, if you don’t have a wall saw fitted with an arbor, is to start by making small grooves starting from the bottom while working your way up, stopping at shoulder height.  

Once you’ve reached that height, you can run the wall saw along the concrete to cut a straight line. This is where the outline of your future door will come in handy. Why, you ask? Because it's better to remove small pieces of concrete at a time rather than a whole chunk at once. 

Use scaffolding to cut the top of the door. Once the entire outline has been cut out, simply push out the concrete blocks, while still taking all necessary precautions to not hurt yourself. 

Also, make sure no one is standing on the other side of the wall before knocking down the concrete blocks.