You can lay new concrete on top of old concrete, but any unresolved issues with the existing concrete, such as cracks or frost, will be carried over to the new layer. To maximize slab life, it's best to pour the new concrete at least two inches thick. With a solid foundation, a well-poured concrete slab can last up to 40 years. The simple answer is yes, you can pour new concrete over existing concrete.
However, there are a few things to consider before making a final decision. Yes, you can put new concrete on top of old concrete as long as there are no issues such as significant cracks or frost elevations with the existing concrete. A new layer of concrete should measure approximately two inches to ensure even and strong coverage. Pouring new concrete onto existing slabs is simple and efficient, as long as the existing slab is in good condition.
If the existing slab is severely damaged, it should be removed and replaced with a new slab. Before pouring the new concrete, you'll need to thoroughly clean the old concrete surface and use a suitable concrete bonding agent to meet all structural requirements. Adding a new layer of concrete to an existing surface will raise the level significantly, which could cause a problem if it is a path or patio that leads to the door, meaning there may not be enough space for the door to open. For this reason, the concrete used to fill the pothole must be carefully designed and a protective layer applied to the area between the repair and the existing slab.
You should use a type of reinforcement, such as fiber mesh or reinforcing bar, to help control and prevent any cracks that may develop as the concrete sets. Screeds are often used to improve the finish of existing concrete for aesthetic purposes or to prepare for other finishing operations. If your concrete has large cracks, it's best to remove old concrete, solve the problem, and pour new concrete. Yes, coating a sunken section of concrete with a new layer of sand-cement mix can raise the sunken section to re-align with the rest of the area.
If these conditions are sufficiently met, then the bond must be strong enough for a new layer of concrete. To maintain your steps, sweep and hose them regularly to remove debris that could wear down their surface. Small steps that extend from a patio or from your home can be covered with a new layer of concrete if properly joined. A bonding adhesive is used on the concrete to ensure that the new layer adheres properly to the existing one.
This bonding agent will be painted over the old concrete to ensure that the new layer adheres successfully.