You might be wondering if you can pour new concrete over the old one. While concrete is built to last, it doesn’t last forever. Over time, it starts to wear down, cracks begin to form, and bits of concrete chip away here and there—none of which contributes to the aesthetics of your home.
When you discover that the concrete that surrounds your house is starting to crack, you might be wondering how you can replace it. You could either break all the old concrete and pour a new one, but that will take a lot of effort and time. So you can pour new concrete over the old one. Here’s the answer: yes, you can, but only with proper preparation.
Here’s how to do it:
Clean the Site
Before you begin any pouring, you must remove as much grime, dirt, and any other loose material on the surface to allow proper adhesion of the new concrete to the old one.
If you discover hard-to-remove substances, such as oil stains, you need to chip them out. You can easily do this by using a hammer and a chisel to chip away at the stained area and sweeping the area of any loose particles after you’re finished. Don’t forget to wear safety equipment.
If the stain stretches over a large area, chipping might be out of the question. In this case, you’ll need to cover the stain with a sealant to allow proper bonding when you pour the concrete mix.
Set Up a Mold
When you pour fresh concrete on a surface, you’ll typically set up a framework to ensure that it sets in the right shape. Well, you do the same thing even when you pour it over old concrete.
To do this properly, dig around the area you’re working on where you can place wooden forms. Ensure that the wooden forms rise at least one or two inches above the surface of the old concrete to allow a fresh layer to set. Don’t forget to coat the interior of the forms with oil, such as vegetable oil, for easy removal after the concrete has set.
Apply a Bonding Agent
To make sure that the new concrete sets appropriately, use a commercial bonding agent. Paint the bonding agent over the concrete surface before you start the pouring process.
Another way you ensure a good bond is to make a scratch coat by creating a wet concrete mix. Using gloves, use this concrete mix to fill any crack you find. The great thing about this is that you don’t have to wait for this mix to dry up. You can start pouring new concrete right away.
Pour the New Concrete
Once the old concrete has been thoroughly coated with the bonding agent, you can start by pouring the new mix onto it. Ensure that this mixture is “drier,” like a dough with little water. Spread the mix thoroughly over the old concrete, evenly distributing it across the mold you set up.
Once you finish pouring it, smooth the surface by using a piece of wood or any other tool, then add the necessary textures on the fresh pour. Cover the entire surface with plastic, and let it dry for at least a week before you do anything with the concrete.
While this is a way to help you save time and money by not having to replace the old concrete entirely, it might not be a permanent fix. If you start to experience the same cracks as you did previously, you’ll need to start from scratch and replace the entire fixture. That said, you can always contact your local concrete contractor to help you with the job.
We’re a commercial concrete contractor in the Bay Area, get in touch with us to see how we can help.