What is the difference between rebar and wire mesh?
A little knowledge goes a long way in helping you make an informed decision when hiring a contractor. If you are considering pouring a new concrete driveway, you may be asked to decide whether to use wire mesh or rebar for support. If you have no idea how to answer that question, this article will provide a short overview to give you an informed decision.
The wire mesh is made of cold reduced deformed steel. It comes to the contractor in a roll which, when laid out, is a series of open squares. Imagine a square chicken wire made of thick steel bars. The bars have ridges to help the concrete adhere to them. Wire mesh is used to add strength to concrete. First, it is there to provide support during the “green” period when the concrete is setting. Then it helps maintain the integrity of the concrete against cracking throughout its life.
The rebar, abbreviated as “rebar,” is also made of steel. They are rounded bars with ridges that measure in sizes that vary by a thickness of 1/8 of an inch. Also used as a support, reinforcing bars are usually individually placed in squares larger than wire mesh. The rebar is an important component to add strength and maintain the structure when cracking occurs.
So which one did you choose?
Wire mesh is cheaper than rod. First of all, the wire mesh is made of thinner steel bars, so there are fewer materials. As you may recall, it can be rolled up. And secondly, because it comes on a roll, the installation work is less intensive. The cost of the rebar will depend on the thickness of the bars and will ultimately increase your labor costs.
Rebar is definitely the strongest candidate for support. However, with that said, if we’re talking about a four-inch-thick residential driveway (four-inches is the recommended thickness for driveways under 10,000 pounds), the mesh works fine. In fact, many contractors consider rebar for residential jobs to be excessive. If you are looking for a thicker driveway because you plan to have heavy trucks or RV parked on it, then rebar is a good suggestion.
Both wire mesh and rebar cannot prevent cracking, but they are helpful in holding concrete together when cracking occurs. Steel behaves similar to concrete in the way it expands and contracts during hot and cold temperatures, which is why it is used in concrete slabs. Likewise, the mesh and rebar will prevent small cracks from expanding further. The wire mesh must be positioned correctly to best serve the concrete. It should be directly in the middle of the slab. So a four-inch slab should have a two-inch deep wire mesh. If exposed to air, it can eventually rust and cause cracks. But a good contractor will make sure that doesn’t happen. Some contractors feel that the smaller squares of the mesh and the thinner steel allow for greater flexibility as contractions occur in the concrete, preventing cracking better than rebar.
The myth of strength
When people talk about mesh or rebar and compare them to determine their strength, an important part of the discussion should focus on the based of the concrete slab. Neither wire mesh nor rebar will do their job if the bottom of the slab is not positioned properly to hold the concrete.