Can Cinder Block Be Installed on Compacted Stone?

Drainage

• The most important aspect of building a block wall is ensuring that it stands up to the test of time. Drainage is important because any type of soil buckling will transfer up through the wall, forcing the blocks to crack, heave or otherwise break, which destroys the integrity of the entire structure. Whether you are building a cosmetic block wall or a load-bearing wall, compacted stone is a requirement as a base layer.

Footers

• While not all block walls require footers, some of them do. For example, garden retaining walls that are less than 4 feet in height do not require a footer. Instead, you can install the block directly on top of a compacted layer of sand and stone. Foundations and other load-bearing walls, on the other hand, require a poured concrete footer, which must be installed on top of a layer of compacted stone to provide a level base for the wall.

Sand

• A compacted layer of sand is generally used on top of a layer of compacted stone to provide a solid base for block walls. However, if you live in an area where there is already sandy soil in place, you may not need to include a layer of sand. Instead, you can compact the soil before you compact the rock and then put the block wall on top of those compacted layers. Always talk with a structural engineer for load-bearing walls to ensure their safety.

Soil Type

• The type of soil you are dealing with will determine whether or not you can put the block wall and footers directly on top of the compacted rock layer, or if you need to include a layer of sand first. Sand works as a cushion for the wall so it settles slowly over the years rather than all at once. If a wall settles too fast, it will shear off in sections, creating vertical shears where two sections of the wall are at different heights due to rapid, uneven settling.