Concrete is the material of choice for most patio projects. It’s strong, easy to work with, and can be finished in a wide variety of textures and colours. It is usually strengthened by a material known as rebar, which is short for “reinforcing bar.” Rebar isn’t just important for large buildings – a new patio requires it, too!
What Does Rebar Do For A Concrete Patio?
As their name suggests, these carbon steel bars are used to reinforce the concrete. Rebar improves the tensile strength of the concrete, which is weak in unreinforced concrete. Because it vastly improves the tensile strength of the material, rebar minimizes cracking caused by the shrinking and swelling that occurs with fluctuating temperatures and weather conditions. The properly prepared ground beneath the patio provides most of the support for the concrete, but rebar helps keep the slab from breaking if the soil under the slab sinks or shifts over time.
You might notice rebar has a ribbed appearance. The surface deformation is done to help mechanically bind the steel to the concrete and strengthen the integrity of the finished structure. It’s amazing how simple materials, when combined, make such a strong structure!
Rebar In A Concrete Patio
Rebar size and quantity can vary based on the size of the job. Residential projects use three different sizes known as #3, #4, and #5 rebar. Numbers 4 and 5 are stronger and thicker, making them the best choice for walls, foundations, and columns. For a concrete patio, you don’t need as thick steel, so we would use #3 rebar. This type has a 3/8-inch diameter, making it the lightest of the three.
No matter how big the patio, the rebar must be installed to very precise measurements because it has a minimum yield strength. If the bars are not properly spaced out, it will minimize the strength of the concrete and cracks will develop. For a concrete patio, the #3 rebar should be placed every 60 centimetres, or roughly every 24 inches, both vertically and horizontally to form a neat grid pattern inside the area where you will have the concrete poured.
The rebar should have support when it is installed so that the grid will not sag. These supports must be at a proper height so that the grid of rebar will be in the middle of the concrete. The ends of the rebar should end about five centimetres from the edges of the space cleared out for the patio. You can have the concrete poured once the grid has properly been laid out.
The concrete should flow around the grid completely without any rebar poking out. After the concrete has been evenly spread out, the patio is covered with plastic and left to cure for a week. The concrete must stay moist so that the chemical reaction that cures the material can continue. The rebar will prevent concrete from cracking as it goes through this process.