You probably know where there's concrete in your house. Your foundation might be poured concrete or you house might sit on a concrete slab like my house being built in Florida (pictured above). What you're probably not as familiar with are the somewhat strange, thin metal bars that are buried in the concrete to make it stronger. The rebar above looks rather funny too with the little plastic hats sitting on top of them.
Do you want to learn more about building, repairing and/or updating your home? Our glossary can help you learn the words you'll use on your journey.
Why Does Concrete Need Rebar?
Concrete is very strong when it's compressed. Called compressive strength, concrete can withstand 4,000 psi (pounds per square inch). In contrast, concrete's tensile strength is very low at about 400 psi. So rebar with its higher tension strength, is added to concrete to help prevent concrete from cracking when forces try to pull it apart.
What are the Different Types of Rebar?
Some of the names used for rebar identify steel as it's main component. Also called reinforcing steel or reinforcement steel, rebar is used as a tension device in reinforced concrete and reinforced masonry structures like my house built from concrete blocks. The surface is often deformed (photo above) to promote a better bond with the concrete.
As with all building materials, there are lots of different products emphasizing different traits. Here's an article by a manufacturer of building products and construction tools that offers a nice overview. In suummary, here are the most important characteristics:
- Length and diameter of rebar, which is used extensively in commercial construction from high-rise buildings to bridges.
- Steel is the most common material while other options include composite bars made of carbon fiber, glass fiber and basalt fiber. Bamboo is now being used as an alternative to reinforcing steel which is pretty amazing.
- Coatings like an epoxy resin are used to resist corrosion. The added cost limits use to environments like saltwater that demand this.
The cost is relatively low (ranging from just over $2.00 to more than $10 at Lowe's) until you realize how much is used in construction. There's a lot more metal around the perimeter of a house. But when you look closely at the photo below, you can see a grid of bars laying close to the ground. That's a lot of rebar!
More Resources on Rebar and Concrete
If you love numbers or simply want to learn more about these building materials, here are some articles I found while researching and writing this post. There are many building materials you never see but each one plays an important role in how your house is built.
- Civil Engineering Forum articles on Concrete in Compression and Concrete in Tension.
- What are the Different Types of Rebar? Does it Matter?
- Types of Rebars: Applications, Uses and Specs.