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How To Break Up a Concrete Slab

There’s a reason concrete is so popular; not only is this material relatively inexpensive, but it’s also incredibly long-lasting and durable! But what happens when you need to remove an old and tired concrete surface? 

Well, there are actually a few options available. Here’s how to break up a concrete slab with a heavy-duty concrete breaker.

The first step in any paving or driveway installation is removing an old, worn surface. We’ve been tasked with eliminating this material countless times over the years. The process always begins with an analysis of the slab’s thickness, alongside whether the concrete is cracked or damaged.

Breaking Up Concrete 

Concrete can be broken up in three ways: by hand, with chemicals or with power tools. Concrete slabs no thicker than 3” can usually be broken up using a regular old sledgehammer, though slabs any thicker will require either a controlled demolition using special chemicals or the use of power tools. 

Regardless of which method you choose, you must always wear appropriate protective clothing, including: 

  • Eye protection
  • Work gloves
  • Thick boots
  • Face mask

By hand 

  1. Start by digging out the earth around the perimeter of your slab to work out its thickness and create a void to prevent the ground from absorbing the blows from your sledgehammer. Dig 1ft from the slab’s edge to create a 1” gap under the surface.
  2. Splash some water onto the area to prevent dust. Grab your sledgehammer with your dominant hand close to the head and your other hand towards the end of the handle. Strike the slab’s edges above the void until the concrete breaks apart. 
  3. For sections that split but don’t fully break, insert a pry-bar into the cracks and wiggle it around until you can fit your gloved fingers inside, then pull the pieces away by hand. 
  4. Repeat these steps until the slab is entirely broken, then remove the rubble using a wheelbarrow or dolly to be collected or disposed of appropriately.

With chemicals

  1. Using chemicals is much less labour-intensive, but they come with their own risks. Most brands use calcium oxide as their active ingredient, which can damage the skin or irritate the lungs if inhaled, so always wear protective equipment.
  2. Begin by using a 1.5” drill bit to create several holes spaced 1ft apart across the entire surface of the slab. These holes should extend down to around 80% of the concrete’s overall depth.
  3. Mix the solution to the manufacturer’s guidelines, which in most cases will involve combining your powdered chemical base with cold water until smooth and uniform throughout.
  4. Pour the mixture into each hole and wait for at least 12 hours for the solution to begin expanding. Some brands can take 24-48 hours to break apart concrete fully, and you’ll need to shelter the surface from sunlight, wind and rain for the duration of this time.

Using a breaker

First things first, you need to know the answer to, what is a concrete breaker? After that, then you can undertake the task at hand.

  1. For slabs thicker than 4”, a breaker (AKA a jackhammer) will usually be your best bet. This method isn’t dissimilar to using hand tools, though you’ll need to don some ear protection as these things can be incredibly loud!
  2. Start by positioning the chisel head towards one corner of the slab, then switch it on as you hold the device upright; this will focus the force on one point. 
  3. Once a section has broken off, move around 2” back and repeat the process, ensuring the device is always upright.
  4. Work from the corners into the centre of the slab, and remember you can dig a void beneath any areas giving you trouble and use a pry-bar to break apart any stubborn chunks. 

Tips For Breaking Thicker Concrete 

When breaking thick concrete many people ask us, what size concrete breaker do I need? This guide will explain all.

  • Dig voids beneath the slab to prevent force absorption 
  • Drill holes into the surface to weaken the structure
  • Use a more powerful petrol-fueled hydraulic breaker
  • Hire an excavator to lift the slab slightly off the ground
  • Hire a professional to cut the concrete with a thermal lance

Last Word

With that, you should have all the information needed to remove any old, cracked or worn concrete surfaces causing you grief! Always begin by digging around the slab to work out its depth, then choose a method fitting for the size of slab you’re dealing with.

Concrete thinner than 3” can easily be broken up with hand tools, though thicker surfaces will generally require a breaker, whilst any sized slab can be broken up using chemicals, though you’ll need to wait a few days for the solution to get to work!