Breaking concrete is never an easy project. While it is possible to rent a jackhammer from home improvement stores or rental yards, this can get expensive if the project drags on. Not only that, wielding the jackhammer itself can be a tough, physically demanding task. Instead, many homeowners choose to break their concrete in a more leisurely and less expensive fashion, using a sledgehammer.
The trick to breaking up concrete is to dig underneath the slab before hitting it with the hammer. Undermining the concrete eliminates its external support, making the material much more vulnerable to cracking through and breaking off.
With small slabs of concrete, such as patio squares or air conditioner pads, you can also have one person pry up the slab a few inches, using a demolition bar, while another person strikes the slab with the hammer. Prying up the slab has the same effect as digging underneath it. Alternatively, you can pry up the slab and shove a rock or piece of lumber under the slab to hold it up above the soil.
Call 8-1-1, the national “Call Before You Dig” hotline, to have all underground utility lines marked in your work area before you start the project. It’s not uncommon for electrical, water, and gas lines to run under concrete structures.
Source: The Spruce