The Guide To Building A Retaining Wall & How To Do It
- srcustommasonry
- Jan 10
- 8 min read
There’s a lot of prep work and knowledge that goes into building a long-lasting retaining wall. If this is a project you’ve thought about taking on, keep reading, and we’ll go over the process step by step. We’ll guide you on materials, give you creative ideas, and help you know what to avoid. When you know what things to make a priority and what pitfalls to be aware of, you create something you can be really proud of.
Planning a Retaining Wall
Detailed planning is a must when tackling a project of this magnitude. Start by standing back and taking a good look at your yard. Pay attention to the slope, where water pools after it rains, and how close the wall will be to structures like your house or fence. These details really matter. A wall placed in the wrong spot or without drainage in mind can lead to shifting or water buildup later.
Next, think about the height and purpose of the wall. A short garden wall has very different needs than a taller wall holding back a hillside. Wall height often affects footing depth, drainage requirements, and whether permits are needed. It’s also a good time to decide on materials, since block size and weight play a role in both labor and cost.
Finally, plan the build from start to finish before breaking ground. Mark the layout, measure twice, and make sure you have all tools and materials ready. Rushing into construction usually leads to uneven courses or extra digging later.
Why You Need a Retaining Wall
Most people don’t even think about a retaining wall until their yard starts giving them problems. Maybe dirt keeps washing down the slope every time it rains, or mulch never seems to stay where you put it. Over time, that shifting soil can creep toward your house, driveway, or fence. A retaining wall steps in to keep everything where it belongs and saves you from constantly fixing the same issues.
Retaining walls also make your yard easier to actually use and enjoy. Sloped or uneven spaces can feel frustrating, especially when you want a spot for a patio, a garden, or somewhere to put a trampoline for the kids. By holding back soil, a retaining wall turns awkward ground into usable space. It’s often the difference between a yard you avoid and one you’ll actually spend time in.
How To Build a Retaining Wall
1. Lay out the wall
Use string line and stakes to outline exactly where the wall will go. Double-check measurements and make sure the line flows naturally with your yard. This step sets the tone for everything that follows, so take your time getting it straight and even.
2. Dig the trench
Grab a shovel or trenching shovel and dig along the layout line. The trench should be wide enough to work comfortably and deep enough to support the first course. Keep the bottom as flat as possible and remove loose soil as you go. This is where a wheelbarrow comes in handy if you have access to one.
3. Install the base
Add crushed gravel or paver base to the trench and spread it evenly. Compact it in layers using a hand tamper or plate compactor. This step is critical for keeping the wall level and preventing settling later.
4. Set the first course of blocks
Place the first row of retaining wall blocks on the compacted base. Use a level to check each block side-to-side and front-to-back. Adjust with the rubber mallet as needed. This row needs to be perfect, since every row above it depends on this one.
5. Add drainage components
Line the back of the wall with landscape fabric to keep soil from mixing with gravel. Place the perforated drain pipe behind the first course, making sure it has a clear path for water to escape. Pour drainage gravel behind the blocks to support proper water flow.
6. Stack additional courses
Continue stacking retaining wall blocks, checking they are level as you go. Sweep debris off each block with a broom before placing the next one to ensure a tight fit. Stagger joints for strength and stability.
7. Backfill as you build
As the wall goes up, add drainage gravel and backfill soil behind each course. Compact lightly to reduce future settling. This step helps lock the wall in place as it rises.
8. Install cap blocks
Once the wall reaches its final height, dry-fit the cap blocks to make sure everything lines up. Apply construction adhesive and secure them in place. Use a utility knife to trim landscape fabric if needed.
Tools and Materials For Building a Retaining Wall
Before gathering all the necessary materials and tools, make sure you check with your HOA and local building codes. There might be certain restrictions, requirements, or mandatory permits that could affect your supply list. Here’s what we recommend:
Tools
Shovel or trenching shovel
Circular Saw
Chisel
Hand tamper or plate compactor
Level (2–4 ft works best)
Rubber mallet
Tape measure
String line and stakes
Utility knife
Safety gloves and eye protection
Materials
Retaining wall blocks
Crushed gravel or paver base
Drainage gravel
Landscape fabric
Perforated drain pipe (for drainage)
Cap blocks
Construction adhesive (for caps)
Backfill soil
Prep Work
The most important prep work is getting the layout right before you dig anything. Take time to mark the wall’s path clearly and step back to look at it from different angles. What looks good on paper can feel off once you’re standing in the yard. Making small adjustments now is way easier than fixing a crooked wall later.
Another big part of prep is understanding your soil and slope. Some dirt is loose and crumbly, while other soil is heavy and stubborn. Knowing what you’re working with helps you plan how much digging and base work is needed. It also sets realistic expectations for how long the project will take and how much effort it’ll require.
Good preparation also means being honest about how much time and energy you have to dedicate to this big project. Retaining walls are physical projects, and they usually take longer than expected. Clearing the area, staging materials nearby, and setting aside uninterrupted work time make a huge difference.
How Deep Should The Footing Be?
The base of any retaining wall is super important to get right because it can make or break the entire project. The footing, or first row of your wall, in most cases, should be about 4-6 inches below finished grade for compacted base material, with the first course of blocks partially buried. A good rule of thumb is to have roughly half of the first block below ground level so the wall can resist shifting and pressure over time.
Width matters just as much as depth. The footing is typically around 12 inches wide, or about twice the width of the retaining wall block you’re using. This extra width helps spread the load and keeps the wall stable, especially as soil expands and contracts. Once the trench is dug, a well-compacted gravel base is essential before setting the first row.
How to Lay Retaining Wall Blocks
Start with a clean, flat working line
Stretch a string line where the face of the wall will be. This keeps you from “drifting” as you lay bricks. It’s surprisingly easy to start straight and end up with a gentle curve you didn’t plan.
Lay the first brick like it’s the only one that matters
Set the first brick, check it for level, then set the next one tight against it. Tap into place with a rubber mallet. Keep checking the level as you go. If the first row is even slightly off, you’ll fight it the whole way up.
Keep the contact surfaces spotless
Before you set the next brick, brush off any dirt or gravel on the one below. Even small pebbles can make bricks wobble. A quick sweep saves a lot of redoing later.
Stagger your joints
Don’t stack bricks so the vertical seams line up. Offset them like you would with regular brickwork. This makes the wall stronger and helps it look more “finished” instead of like a stack of squares.
Check alignment often, not just when it looks wrong
Every few bricks, step back and sight down the face of the wall. Use your string line and level to make sure you’re not slowly leaning in or out. Little corrections early are easy. Big corrections later are not.
Build in “lock” as you go
As you add rows, make sure each brick is seated fully and feels stable. If your blocks have lips, grooves, or a locking edge, keep them engaged the same way every time.
Finish the top cleanly
When you’re happy with the final row, place cap bricks for a cleaner look. Dry-fit them first so the spacing looks right, then glue them down, as mentioned earlier.
How To Build A Retaining Wall On a Slope
Building a retaining wall on a slope adds a bit of complicated planning that flat ground just doesn’t require. Instead of a straight trench at one height, the base usually has to step down as the slope changes. That means you’re working in sections, making sure each step stays level before moving on. It takes more patience, but it helps the wall follow the natural grade without looking awkward.
The layout also matters more on sloped ground. You’ll want to pay close attention to how the wall meets the slope at both ends. Poor transitions can leave exposed soil or create weak spots that don’t hold up well. On a slope, even small alignment issues stand out visually, so checking your line and spacing often becomes more important.
Backfilling on a slope is different, too. Gravity works against you, so material can shift if you rush it. Working in shorter sections and keeping everything snug as you go helps the wall settle evenly.
Retaining Wall Ideas
Retaining Wall Flower Bed
This is one of the most popular uses. It keeps soil and mulch in place and makes planting easier to maintain.
Retaining Wall With Bricks
Brick walls give a more classic, finished look. They work well when you want the wall to blend in with your home or existing hardscaping.
Retaining Wall With Cinder Blocks
A practical, budget-friendly option. Cinder blocks are sturdy and easy to work with, especially for utility areas or taller walls.
Patio Dining Space
Retaining walls can carve out a flat spot for a table and chairs. It turns an unused slope into a place people actually want to gather.
Terrace to Sloped Yard
Terracing breaks a steep yard into usable levels. It also helps control runoff and makes mowing or walking around the yard much more doable.
Driveway, Walkways, Sidewalks
Walls along driveways or paths keep edges from crumbling. They also make these areas feel more intentional.
Backyard Water Feature or Pond
Retaining walls can frame a pond or small water feature. They help manage elevation changes and create a natural-looking border.
Fire Pit
A low retaining wall can double as seating around a fire pit. It’s a great way to define the space without needing extra furniture.
Custom Mailbox
Using a retaining wall for a mailbox adds curb appeal. It also helps with drainage and erosion near the street.
Backyard Benches
Built-in benches using retaining walls are a great way to save space. They’re sturdy, low-maintenance, and always great for extra seating.
Things To Watch Out For
Before breaking ground on a retaining wall, make sure to call 811 to have underground utilities marked. Gas lines, electrical, water, and communication lines can be buried closer to the surface than you’d expect. One quick call can save you from a potentially dangerous situation and a very costly mistake.
Water management is another major thing to watch out for. Retaining walls don’t usually fail because of weight alone; they fail because of trapped water. Poor drainage can create pressure behind the wall and cause it to lean or collapse over time. Planning for gravel backfill, drainage fabric, and a drain pipe helps prevent all these problems down the road.
Also, remember to be realistic about wall height and soil conditions. Taller walls require deeper footings, more reinforcement, and sometimes permits or engineering. Soft or clay-heavy soil may need extra preparation to stay stable. Rushing the base, skipping compaction, or eyeballing the level instead of checking it carefully are common mistakes.
Building a Retaining Wall: Conclusion
At the end of the day, a retaining wall is about more than holding back dirt. It’s about making your space work better, last longer, and feel more intentional. When the planning, prep, and execution are done right, a retaining wall quietly solves problems while adding real value to your property.
At S&R Custom Masonry, we bring years of hands-on experience designing and building retaining walls for all kinds of landscapes across SLC. Homeowners trust us because we focus on doing things the right way, not the rushed way. Our reputation comes from consistent craftsmanship, clear communication, and results that hold up year after year.
Comments