A little knowledge goes a long way in helping you make an informed decision when hiring a contractor. If you’re considering pouring a new concrete driveway, you may be asked to decide whether you want to use wire mesh or rebar for support. If you have no idea how to answer that question, this article will provide a brief overview to give you an informed decision.
Wire mesh
The wire mesh is made of cold reduced deformed steel. It arrives to the contractor in a roll which, when presented, 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. It then helps maintain the integrity of the concrete against cracking throughout its service life.
reinforcing bar
Rebar, short for “rebar”, is also made of steel. They are rounded bars with ridges that measure in sizes ranging in thickness from 1/8 inch. Also used as support, rebar is usually placed individually in larger squares than wire mesh. Rebar is an important component to add strength and maintain the structure when cracking occurs.
So what do you think?
cost
Wire mesh is cheaper than rebar. First of all, wire mesh is made from thinner steel bars, so fewer materials are used. As you will remember, it can be rolled up. And second, because it comes on a roll, the installation work is less labor intensive. The cost of rebar will depend on the thickness of the bars and will ultimately add up to more labor expense.
Support for
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), mesh works fine. In fact, many contractors find rebar for residential work to be overkill. If you’re looking to get a thicker driveway because you plan on having heavy trucks or an RV parked on it, then rebar is a good suggestion.
Cracking
Both wire mesh and rebar cannot prevent cracking, but they are helpful in holding concrete together when cracking occurs. Steel behaves similarly to concrete in the way it expands and contracts during hot and cold temperatures, which is why it is used in concrete slabs. Similarly, the mesh and rebar will prevent small cracks from expanding further. The wire mesh must be placed 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 ultimately rust and crack. But a good contractor will make sure that doesn’t happen. Some contractors feel that the mesh’s smaller squares and 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 reinforcing bars and compare their strength, an important part of the discussion should focus on the base of the concrete slab. Neither the wire mesh nor the rebar will do their job if the bottom of the slab is not placed properly to support the concrete.
