A precast concrete hollow block wall being filled with a concrete mixture to ensure the durability and strength of the wall blocks

If you have installed a precast concrete retaining wall that is made of hollow blocks, you might consider leaving them that way, but doing so can be a costly mistake that can affect the longevity and durability of the wall.

The following factors should encourage you to fill those negative spaces with materials like crushed rock or pea gravel:

Hollow Precast Retaining Walls Are Less Stable

There are a few advantages to erecting a hollow retaining wall, such as its lower manufacturing cost and greater insulation against sound. In some cases, a block retaining wall may use negative spaces for design purposes, which also counts as a hollow retaining wall.

When you use precast concrete retaining walls that consist of hollow blocks, however, it’s important to recognize that the wall won’t be durable enough for your needs. You can increase the wall’s stability by filling the blocks with some form of infill, such as gravel.

Improve Block Adhesion with Infill

When you construct precast retaining walls that consist of concrete blocks, you’ll do so by using an interlocking pattern. A solid block will have a larger surface area for interlocking with the other blocks surrounding it, whereas a hollow block will lack that surface area, resulting in a less adhesive lock.

You can correct that flaw with infill. Filling each block will provide it with a greater surface area and increased weight. Heavier blocks sit more securely, ensuring the interlocking pattern will remain fixed and tight.

Filled Blocks Promote More Efficient Drainage

Rainwater, snow, and ice can all accumulate inside precast retaining walls composed of hollow blocks. As temperatures drop and the collected moisture freezes (and by proxy, expands), the added stress on the concrete will cause it to crack. You may end up with entire sections of a retaining wall that need replacing.

You can avoid a situation like that entirely by filling your hollow blocks with gravel or other stones. The area is already filled with matter, so rainwater and snow will be unable to amass inside the blocks, instead running off of them and accumulating on the ground.

Know How to Fill Hollow Blocks

As you fill the hollow blocks of your precast retaining walls, avoid using products like soil and sand, as these materials can absorb moisture and expand, causing the same issues. Instead, use rock, stones, or gravel.

As you fill in the blocks in sequence, make sure to add backfill as support behind the retaining wall.

You’ll need higher backfill to support the wall on the same side as any terrain you want to protect.

Finally, make sure the backfill and the infill in the blocks are compact. Doing so might require more infill material than you initially planned, but packing the material will be necessary for the wall’s integrity.

We Make Building a Retaining Wall Easy

American Precast Concrete can make it easier for you to erect a retaining wall on your property. Contact one of our representatives today to discover how you can customize our precast concrete wall systems products to build your retaining wall.