Backfill the Wall Once you've laid all the courses of blocks, you can fill in the area behind the wall. Backfill the wall with gravel or sand. If you use sand, first cover the backside of the retaining wall with landscape fabric. This will keep the sand from seeping between the blocks.
Yes. A base layer of gravel does more than just act as a flat spot for the block, it helps keep them from shifting and drains water as well.
While some walls only need soil, compacted gravel backfill is the go-to for applications requiring durability and drainage. ✨ Why gravel backfill works: ✔️ Adds structure and stability. ✔️ Prevents water buildup with proper drainage. ✔️ Improves the longevity of your retaining wall. #RetainingWall #RetainingWallBlock.
When building a retaining wall, the normal build practice is to use 3/4 inch drain rock behind the wall, in order to facilitate drainage down the hill that you are holding back with the wall. If you want to use a retaining wall just as a decoration on a raised bed that is two feet by 30 feet long,...
Rules of thumb commonly used by designers to establish the geometry of the wall include (refer to diagram): Base width = 1/2 to 1/3 of the height of the wall. Base thickness = 1/8 of the height of the wall but not less than 12 inches. Stem thickness = 6 inches + ¼ inch for each foot of wall height.
Soil saturation is the most common external factor that causes retaining wall failure, but there are many ways to prevent it.
The base material should only consist of angular, sharp-edged particles such as ¾-inch minus gravel. The various-sized crushed gravel with the fines helps ensure the right amount of compaction. Round rocks, such as pea gravel, roll and dislodge under pressure resulting in failure of the retaining wall.
Don't Forget To Backfill Behind Your Retaining Wall
Neglecting to backfill properly can lead to reduced support, increased pressure on the wall, and the possible collapse of the wall.
A retaining wall should have AT LEAST 12" (30 cm) of gravel (or other similar material; see text for more info) behind its entire length and height. Should be equal to or slightly larger than wall length.
A concrete block retaining wall is one of the most common versions because it is simple and relatively inexpensive to build. Because concrete blocks are available in various sizes as well, they are a versatile option, especially when filled with concrete and/or rebar.
One major thing to avoid when building your retaining wall is lining the back of your wall with plastic sheeting as this will surely result in the pooling of water behind the wall.
In order to provide proper drainage, at least 12 inches of granular backfill (gravel or a similar aggregate) should be installed directly behind the wall. Compacted native soil can be used to backfill the rest of the space behind the wall.
We recommend a 10-20mm clean, free drainage aggregate such as river stones or coarse crushed rock. It is imperative that the material is free from any soil, sand or other fines to ensure that water can flow freely through the drainage area and away from the back of the wall.
Dig A Trench To Outline The Space
Ensure the trench is wide enough to support both the retaining walls as well as any plants or flowers that will be added. Keep in mind that the fill dirt will act as a base for the entire feature, meaning any wall layers and plants should have a layer of fill dirt underneath it.
Behind any retaining wall should be a thick layer of dry drainage material that separates the wall from soil. Backfill can be made with gravel, stones or crushed rock, also referred to as aggregate.
Absolutely! Even a 2-foot retaining wall needs an effective drainage system. Without it, water can build up behind the wall, leading to pressure that might cause the wall to lean or even collapse. All walls need systems to manage water effectively, preventing damage over time.
To compact the soil around a structure, lay out soaker hose 1 to 1-1/2 feet from building walls. For the best performance, limit water pressure to 25 psi. You may need to install a pressure limiter on your faucet. Water the ground for 10 to 15 minutes two to three times per day.
Choosing the right backfill material behind the retaining wall is crucial in preventing soil erosion. It is recommended to use granular, well-draining materials such as crushed stone or gravel for backfill, rather than fine-textured soils.
Step 2: Prepare the base of the wall. Add a base of gravel. We recommend #57 Gravel, at about 1–3-inch thickness and then tamp it down with a tamper to make sure the base is level.
Sometimes retaining walls are designed as cantilevers. These typically include reinforcement and rely on the combined strength of the concrete and reinforcement to resist bending at the base of the wall. In that case, plan on waiting seven days before placing the full depth of backfill.
Disadvantages of Retaining Walls
One significant disadvantage is that they can be expensive to build. Retaining walls require careful planning and engineering to ensure they are strong enough to hold back the soil. Another disadvantage of retaining walls is that they can be difficult to maintain.
Discover how the right retaining wall can reduce soil erosion, improve water drainage, and transform your property. Depending on the material, soil, and groundwater, a permanent retaining wall can last anywhere from 25 to 100 years.