Pouring new concrete over old concrete can be a great way to save time and money on a project. However, it is important to understand the potential drawbacks of this approach before making a decision. The biggest issue with pouring new concrete over old is that it can reduce the lifespan of the area. For example, a new concrete building on a new gravel base will typically last up to 40 years, but if the old concrete is not in good condition, it can significantly reduce the life of your floors over time.
If done correctly, however, new concrete can often be poured over an existing slab. For this to be feasible, the contractor must pour at least 2 inches thick, use smaller aggregates, and incorporate reinforcements such as welded wire mesh or mixed fiber into the concrete. Preparation is key when pouring a concrete slab. The soil must be dug to the right depth and then smoothed with a flat rake for a level surface.
The floor should then be tamped with a manual or mechanical rammer. A layer of small, rounded gravel should also be poured for additional drainage needs. If you are going to repair damaged concrete, you will need the new concrete to adhere to the old one for the repair to last. The crusher run (a mixture of crushed stone and stone dust) is one of the best base materials for flat concrete works.
The patch or area where you are adding new concrete will be raised compared to the rest of the house. Understanding how to make concrete bond with other materials is essential when repairing old concrete or pouring new concrete. For large projects, coarse aggregates have large gravel and are more durable, ensuring that concrete is stronger and more durable. If these conditions are met sufficiently, then the joint must be strong enough to withstand a new layer of concrete.
For this reason, you should use a very reliable concrete adhesive if you want to glue or join two concrete surfaces together. Despite the fact that it is possible to join an old concrete to a new one, you need to do it in the best way to prevent gaps or cracks from occurring. An adhesive adhesive must first be painted over the existing concrete for the fresh concrete to adhere successfully. This can be avoided by preventing the new concrete from completely bonding to the old concrete, allowing each one to shrink and expand on its own when the temperature changes. Although not ideal, adding a new layer of concrete on top of old concrete is still an option if done correctly. If there are spills that have leaked onto the floor surface, it may be necessary to grind or mill to remove the top few millimeters of the existing floor surface to clean the concrete. Let's take a look at other disadvantages of using old concrete as a fill for new concrete to help you decide if it's the right choice for your project.
While it is possible to use old concrete as a base for new concrete, many factors will determine whether the concrete is strong enough to accommodate the new batch.