Tools and Materials
Tools
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Planning a Block Retaining Wall
There are several retaining wall systems to consider when choosing the building materials for your wall. You can choose regular blocks that simply stack together for a gravity-held wall, a block system that works with pins for easy and secure assembly or block with an interlocking lip as we did for this project. The lip creates a locking flange on the block that provides reinforcement, making your retaining wall ideas easier to accomplish. Interlocking retaining wall block can be stacked to build walls up to 24 to 36 inches high, depending on the size of the block. Follow the block manufacturer's instructions for wall height limits.
Plan your layout. Avoid having downspouts pointed at the retaining wall and, if the layout is against the house, keep soil and mulch well below the siding.
Your retaining wall design will determine how you mark the area. To mark a free-form layout, use a rope or hose to outline the shape. Then use a shovel to mark the outline. For straight lines, mark the entire bed area with stakes, string and marking paint. Mark curved corners by tying a string to a stake that's equidistant to the edge — creating a compass — and spraying the curves with marking paint.
To determine how many blocks you'll need per row, divide the total length of the wall by the length of a block. To see how many rows you'll need, divide the ideal wall height by the height of a block; account for the first row to be half-buried. See our Retaining Wall Block Calculator and Planning for a Block Retaining Wall for more information on estimating project materials.
Before you buy materials or begin work installing a retaining wall, check local building codes and your homeowners association regulations to see if there are any restrictions or requirements you need to follow. A permit may be mandatory in some areas.
Purchase 10% more block than your estimate. The excess should account for breakage, cutting and replacements for future repairs. Block can be heavy so wear a back support if necessary. You may want to enlist a helper to share the work. Consider having the material delivered.
Shop Tools and Materials for a Block Retaining Wall
Get your retaining wall started right by staging the tools and materials you'll need for the project.
Key Retaining Wall Tools
Key Materials for Building a Block Wall
Prep and Lay the Retaining Wall Block
Now that you have a plan and a layout for your retaining wall DIY project, prep the area and begin building the retaining wall. Here’s how.
Prepare the Foundation
Build the Retaining Wall
Retaining Wall Ideas
Once you know how to build a block retaining wall, think about some different DIY landscape ideas for retaining walls.
Mix and match different block colors to create a custom wall. Or capture the perfect look by choosing your style of block. In addition to block with beveled or straight faces, you can find block with the look of tumbled natural stone or rounded fieldstone, chiseled-face block with the appearance of worked stone or block that creates the look of a stacked-stone retaining wall.
And, while retaining walls are perfect for creating raised planting beds, there are other hardscaping design ideas for incorporating a retaining wall into your landscape.
- Break up a lawn with raised beds, adding new textures, colors and planting opportunities, while reducing lawn maintenance.
- Go beyond a basic flower bed with stair-stepped walls for multilevel plantings.
- Define a patio space while adding planting opportunities. Better yet, plan your retaining wall design to create nooks for a dining space, cooking area, fire pit or other conversation areas.
- Add terraces to a sloped yard or a hillside to make the landscape more usable and help control erosion.
- Define a driveway, sidewalk or walkway with a course of retaining wall block, or beautify them by lining them with raised flower beds.
- Incorporate a raised bed into a backyard pond or water feature.
Beyond standard retaining wall ideas, consider other uses for retaining wall block. Some wall block can work for a fire pit, benches, mailbox surrounds or decorative columns and walls.
Ready to take on some landscaping? We've got a variety of weekend projects you can shop to create fire pits, tree rings, planters and more.
Project Variation: Using Railroad Ties as a Retaining Wall
Once you know the basic steps for building a block retaining wall, you can also build a wood retaining wall using railroad ties.
What Are Railroad Ties?
Railroad ties are a unique and useful building material for those looking to boost their landscape or prevent erosion with a retaining wall. Railroad ties were originally used to provide a stable base for railroad tracks. Now that many railways are using metal structures to replace traditional wooden ties, reclaimed ties are being put to good use in a variety of professional and do-it-yourself projects.
How to Build a Railroad Tie Retaining Wall
Using railroad ties for a retaining wall requires some customization, and every layout will differ depending on the location as well as a variety of other factors such as the slope of your landscape. Below is a general overview of the most important project steps so you can adapt them to your own landscape. Keep in mind that the order of some of the steps may vary.
Instructions
Frequently Asked Questions
Here are some answers to frequently asked questions about building a retaining wall.
What Blocks Should You Use for Retaining Walls?
There are several block retaining wall systems to consider when choosing how you want to design your wall. There are regular blocks that simply stack together for a gravity-held wall. For a stronger block system, look at one that works with pins for easy and secure assembly. There is also interlocking block, with a lip that creates a locking edge on the block for fortification.
What Should You Watch Out for When Building a Retaining Wall?
The most important thing in constructing a block wall should be controlling water and making sure you have proper drainage for your wall. Inadequate drainage will cause the wall structure to weaken, with the potential for leaning, bulging and eventual collapse. Using landscape fabric and gravel along the wall base will aid in helping water drain safely and not saturate the soil.
How Deep Should a Footing Be for a Retaining Wall?
The footing, or first row of your retaining wall, should be about 4 to 6 inches deep and about 12 inches wide, or twice the width of the block you are using. The blocks should sit about halfway into the soil.