How much gravel do you put under a concrete slab? You will need 3 inches of gravel under a concrete slab that is 4 inches thick. More gravel is better, but 3 inches is the minimum amount of gravel you should have with a 4” slab. Use ¾” washed and screened gravel, then compact it to level.
How Much Gravel Under Concrete?
Gravel is an important component of any concrete project. It helps form a strong foundation for the concrete and improves its durability.
The amount of gravel used under concrete will vary depending on the project and its size. When pouring concrete for a driveway or patio, a minimum of 4 inches of gravel should be used as a base.
This will provide a stable, durable foundation for the concrete. If more weight is expected, such as a driveway with a heavy vehicle, then a thicker base of 6 inches of gravel should be used.
For a sidewalk, a minimum of 3 inches of gravel should be used. This will provide a stable foundation for the concrete and reduce the risk of cracking and shifting.
For heavier foot traffic or a longer sidewalk, 4 to 5 inches of gravel should be used to provide a strong foundation. Foundations for buildings should always use a minimum of 8 inches of gravel.
This will provide a strong, stable base and help prevent cracking and shifting of the concrete. For larger, more complex projects, more gravel may be needed in order to provide a strong foundation.
When placing gravel under concrete, it is important to make sure the gravel is level and free of debris. Any debris, such as sticks or stones, can interfere with