Tips to Set the Perfect Retaining Wall Base Every Time

In both landscaping and hardscaping, a retaining wall is an important option to consider when planning renovations to a yard or site. They provide strong solutions for leveling out sloping sites, providing terraces for recreation, features, or landscaping, and preventing or dramatically reducing erosion by reducing the slope of the land. 

However, it's important to know how to build a retaining wall with preparation, proper retaining wall materials, appropriate tools, and smart techniques that ensure it lasts for a very long time. In this post, we'll look over what a retaining wall is, the tools needed when creating a retaining wall, the steps in the installation process, and the importance of planning for drainage in the finished wall.

What is a Retaining Wall?

A retaining wall is an installation of block, rock, stone, or pavers to turn a single sloped piece of land into two or more flatter sections. In essence, fill is removed from the lower part of the slope and moved to the upper part of the slope, creating two or more terraces that are kept in place by the retaining wall. Removing the slope helps prevent erosion and retain soil, and can also deliver more useable space with an aesthetic appeal.

Though there are many types of retaining walls, the types that are used by most hardscapers are gravity, anchored, or cantilevered, with gravity being the most common. A gravity retaining wall gradually slopes back into the upper section of the tier, so that its weight bears both down against the soil supporting it and back onto the soil behind it. In fragile or loose soils, an anchored approach may be taken to provide additional resistance to soil washing out behind the retaining wall and pushing it forward into the lower terrace, while a cantilevered retaining wall has a slab that extends under the upper tier so that the weight of the soil keeps the wall in place.

Retaining walls are typically used on slopes to prevent soil from eroding, but are also commonly found on patios, in gardens to create raised beds, and similar areas of landscaping and hardscaping design. They provide a range of valuable benefits, but only when installed correctly and with sufficient drainage.

Tools Needed for a Retaining Wall

You'll want to have several essential tools on hand when working on a retaining wall installation. These include:

• Measuring tapes make it easier to determine where and to what extent you'll be removing soil and where you'll be placing your stone and blocks for your retaining wall base.
• Stakes help you lay out the shape and size of your retaining wall, providing you with an easy visual guide to the entire project.
• String can be another essential tool for alignment, and is often run between stakes to provide you with the form of the retaining wall layout, while marking tools allow precise shaping of blocks or pavers.
• Shovels/Grade Rakes are useful for last-minute adaptations to the retaining wall base, to move retaining wall materials, and to handle a range of other small but important tasks on the job site.
• Compactors are used to compact the soil in the area where your retaining wall base will be, as well as to settle and compact drainage materials, such as gravel or stone used behind the wall.
• Hand tampers are good options for tight areas where a compactor may not easily fit.
• Laser levels or altimeters ensure that you'll be able to keep your entire retaining wall flat so that you can prevent issues with stability down the road. This tool is especially important in gravity retaining walls.
• Excavators are a great option for larger retaining walls or in situations where you need to finish the work relatively quickly, as they are able to move large amounts of soil.
• Levels are a great tool for checking the accuracy of your groundwork. Establishing the finished base of your wall will be most accurate if done with the Pave Tool Wall Screed system while reducing time.
• Concrete blocks, stones, or other retaining wall materials. In many situations, concrete wall blocks are used to create retaining walls, creating a beautiful appearance that remains easy to install.
• Clamps are needed to lift the retaining wall materials and can be assisted with an excavator.
• Wheelbarrows help you move material, whether it's the soil that has been dug up, the tools you need to move to different locations along the wall, or materials to their final location.
• Gloves and safety gear, including a back brace if needed. If you're going to have heavy equipment, a safety vest to improve worker visibility may also be helpful. Safety glasses are necessary if you're splitting or cutting material.
• Optional tools include some of Pave Tool Innovators’ specialized tools designed specifically for hardscaping projects.

Steps to Prepare Your Retaining Wall

1. Assess and Plan

To determine what you'll need to build, measure the entire area impacted, determining the length and height of the wall. You may need to check local codes and regulations if your retaining wall exceeds a certain height. Knowing these requirements allows you to design an appropriate retaining wall.

2. Excavate the Foundation

The retaining wall base requires a trench that is wide and deep enough for stability. Extend the base to an area at least 6-8" behind and in front of the blocks to ensure good drainage. Excavate deeply enough for one course of blocks below the surface and a compacted layer (10-12”) of crushed gravel or stone as well as woven stabilization fabric to provide a stable base and allow for trench leveling. We recommend using the Wall Screed to increase accuracy and speed up this tedious task.

3. Base Layer

With the foundation layer leveled, you'll simply lay the first course of blocks on the level foundation.

4. Building Up

With the first layer completed, you'll want to continue stacking your layers. Make sure to offset your block joints to provide superior strength. Always use a clamp to reduce back labor and add a Geo-Grid between layers per specifications.

5. Backfilling

As you complete each layer, add stone to a specified distance then add soil behind the block, compacting it to avoid settling in the future.

Don’t Overlook Proper Drainage

Drainage is of vital importance to your retaining wall's longevity, as it prevents settling, erosion, and damage to the wall by providing a specific, engineered channel for the water to move through. Common drainage solutions include:

• Adding a perforated pipe behind the wall at base level to promote water flow through the dedicated channel along the back of the wall face.
• Using clean stone backfill to promote water flow, providing a channel for the water to move.
• Installing a retaining wall spillway for water to escape, allowing water to weep out from behind the retaining wall and move out beyond the toe of the retaining wall per required specifications.

If drainage is ignored, there can be a wide range of issues, but the most common are soil erosion or loss, or failure of the wall system.

Look to Pave Tool Innovators for Your Hardscaping Help

To create a strong retaining wall, you need to plan, create a strong retaining wall base, stack layers with staggered joints and backfill, and provide good drainage. Having the right tools makes this process much easier. Why not take a few minutes to view our lineup of hardscape-tested products or contact us today for more details?