How To Build A Retaining Wall With Bricks – A Professional Guide

ByJim Boslice Metalworking & Fabrication

To build a brick retaining wall, you must start with a reinforced concrete footing set below the frost line to prevent shifting. Success depends on installing a perforated drainage pipe and gravel backfill to manage hydrostatic pressure behind the wall.

Ensure the wall has a slight backward lean, known as a batter, and include weep holes every few feet to allow water to escape and prevent structural failure.

Building a structural element in your landscape can feel like a daunting task that requires a professional crew. You might worry about the wall leaning, cracking, or even collapsing under the weight of the soil after the first heavy rain.

However, learning how to build a retaining wall with bricks is a manageable project for a dedicated DIYer when you follow the right engineering principles. By focusing on a solid foundation and proper drainage, you can create a feature that adds both beauty and value to your property.

This guide will walk you through every stage of the process, from excavating the trench to the final capping course. We will cover the technical details that ensure your wall remains upright and functional for decades to come.

Understanding the Basics of Brick Retaining Walls

Before you pick up a trowel, you need to understand that a retaining wall is more than just a vertical stack of bricks. It is a structural barrier designed to hold back thousands of pounds of earth and water pressure.

Unlike a decorative garden wall, a retaining wall must resist lateral force. This means the construction methods are more rigorous, requiring a deeper understanding of soil mechanics and load distribution.

When you master how to build a retaining wall with bricks, you are essentially creating a gravity-defying structure. The weight of the bricks and the strength of the mortar must work in harmony with the foundation to stay stable.

The Importance of the Footing

A brick wall is rigid, meaning it does not flex like a dry-stack stone wall. If the ground moves, the wall will crack. To prevent this, you must pour a concrete footing.

This footing acts as a bridge, distributing the weight of the wall over a wider area. It must be placed on undisturbed soil or well-compacted subgrade to prevent settling over time.

Managing Hydrostatic Pressure

The number one killer of retaining walls is water. When soil gets wet, it expands and becomes incredibly heavy. This hydrostatic pressure can easily push a brick wall over if it has nowhere to go.

A successful build always incorporates a drainage system. This usually consists of a gravel layer behind the bricks and a pipe to channel water away from the structure.

Essential Tools and Materials for Your Project

Having the right gear on hand makes the difference between a frustrating weekend and a successful build. Masonry work is physically demanding, so quality tools are your best friends.

You will need standard excavation tools like a pointed shovel, a mattock for breaking up hard soil, and a heavy-duty wheelbarrow. A plate compactor is also highly recommended for the base material.

For the masonry side, ensure you have a high-quality pointing trowel, a mason’s line, a line level, and a 4-foot carpenter’s level. A brick hammer or a masonry saw will be necessary for custom cuts.

Choosing Your Bricks

Not all bricks are created equal. For a retaining wall, you need severe weather (SW) grade bricks. these are designed to withstand direct contact with moist soil and repeated freeze-thaw cycles.

Avoid using “reclaimed” bricks unless you are certain of their density. Soft bricks will absorb water, freeze, and then flake apart (spall) within just a few seasons.

Mortar Selection

For structural retaining walls, you should use Type S or Type M mortar. These mixes have higher compressive strength and better resistance to lateral loads than standard Type N mortar.

Type S is the “gold standard” for DIYers because it offers a great balance of workability and strength. It bonds exceptionally well with the brick and the concrete footing.

How to build a retaining wall with bricks: Step-by-Step

Now that you have your materials, it is time to start the actual construction. Follow these steps carefully, as skipping a single stage can lead to structural issues later on.

Step 1: Excavation and Trenching

Start by marking the layout of your wall using stakes and string. Dig a trench that is twice as wide as the thickness of your brick wall. This provides room for the footing and the drainage gravel.

The depth of the trench depends on your local frost line. In most regions, you want the footing to be at least 12 inches deep, but check local building codes for specific requirements.

Step 2: Pouring the Concrete Footing

Mix your concrete to a firm, peanut butter-like consistency. Pour it into the trench and level it off. It is a pro tip to embed rebar into the wet concrete to increase its tensile strength.

Use a long straightedge to ensure the top of the footing is perfectly level. Let the concrete cure for at least 24 to 48 hours before you begin laying the first course of bricks.

Step 3: Laying the First Course

The first course of bricks is the most critical part of how to build a retaining wall with bricks. If this layer is crooked, every layer above it will be magnified in its error.

Apply a thick bed of mortar to the footing and set your corner bricks first. Use your mason’s line to ensure the bricks in between are perfectly straight and level across the entire span.

Step 4: Building the Wall Body

Continue laying bricks in a running bond pattern, where the joints of one row are centered over the bricks of the row below. This pattern provides the maximum structural integrity.

As you build upward, remember to include a slight “batter.” This means each course is set back about 1/4 inch from the one below it, causing the wall to lean slightly into the hill.

Step 5: Installing the Drainage System

Once the wall is a few courses high, place a perforated 4-inch drainage pipe behind the wall. Wrap the pipe in filter fabric to prevent silt from clogging the holes over time.

Every 4 to 6 feet, leave a vertical mortar joint empty in the first or second course. These are your weep holes, which allow water trapped behind the wall to escape to the front.

Advanced Techniques for Wall Stability

If your wall is higher than three feet, you may need to incorporate additional reinforcement. High walls face significantly more pressure than low garden borders.

One common method is to build a double-thickness wall (two bricks wide). You can tie these two “wythes” together using metal wall ties or by laying “header” bricks every few courses.

Header bricks are laid perpendicular to the wall, spanning across both rows. This locks the two layers together into a single, massive structural unit that is much harder to tip.

Using Deadmen for Extra Support

For very tall walls, you can use “deadmen.” These are structural members that extend back into the hillside and are anchored into the soil. In brickwork, this is often done with reinforced concrete piers.

These anchors use the weight of the soil itself to hold the wall in place. While more complex, they are essential for walls that must support heavy slopes or driveways.

Backfilling and Finishing the Project

Backfilling is not just about throwing dirt behind the wall. It is a functional layer of the structure. Use clean, crushed gravel for the first 6 to 12 inches directly behind the bricks.

This gravel allows water to drop quickly to the drainage pipe rather than soaking into the soil. Only fill the top few inches with topsoil to allow for grass or plantings.

Capping the Wall

The final course of bricks should be a “cap” or “coping” layer. You can use standard bricks laid on their sides (soldier course) or specialized concrete capstones.

The cap protects the interior of the wall from rainwater. Ensure the cap has a slight overhang and a “drip edge” to prevent water from running down the face of the brick and causing stains.

Safety Considerations for Masonry DIYers

Masonry involves heavy lifting and caustic materials. Wet mortar can cause chemical burns on your skin, so always wear waterproof gloves and long sleeves when mixing or applying it.

Protect your eyes with safety glasses, especially when cutting bricks with a saw or hammer. The silica dust produced during cutting is hazardous, so a respirator mask is mandatory.

If you are building a wall higher than four feet, stop and consult a structural engineer. Many municipalities require a permit and professional plans for walls of this height due to the risk of catastrophic failure.

Common Pitfalls to Avoid

One of the biggest mistakes in learning how to build a retaining wall with bricks is ignoring the soil type. Clay soil retains much more water than sandy soil, requiring more robust drainage.

Another error is failing to compact the backfill. If you just toss loose dirt behind the wall, it will eventually settle and pull away, creating voids where water can pool and freeze.

Finally, never use standard mortar for the footing-to-brick connection if you live in a high-moisture area. Use a waterproofing membrane or a specialized masonry sealer on the back of the wall to prevent efflorescence.

Frequently Asked Questions About Building a Brick Retaining Wall

How deep should the footing be for a brick retaining wall?

The footing should generally be at least 12 inches deep or below the local frost line. It should also be at least twice as wide as the wall itself to provide a stable base.

Do I really need a drainage pipe if I have weep holes?

Yes. Weep holes are the exit points, but the drainage pipe is the highway that collects water from the entire length of the wall and brings it to those exits. Without the pipe, water can still build up in pockets.

Can I build a retaining wall with bricks without mortar?

No. Bricks are too light and uniform to be “dry-stacked” for a retaining wall. Unlike heavy, irregular landscape blocks, bricks require mortar joints to create a monolithic structure that can resist soil pressure.

How long does a brick retaining wall last?

A well-built brick retaining wall can last 50 to 100 years. The key to longevity is the quality of the SW-grade bricks and the effectiveness of the drainage system to prevent water damage.

Final Thoughts on Your DIY Retaining Wall

Taking the time to learn how to build a retaining wall with bricks is an investment in your home’s landscape and your own skills as a craftsman. It is a project that rewards patience and precision over speed.

By prioritizing the concrete footing and the drainage gravel, you are building a structure that will stand the test of time. There is a unique satisfaction in seeing a perfectly level, plumb brick wall that you built with your own hands.

Remember to work safely, check your levels constantly, and don’t rush the curing process. Once the mortar sets and the backfill is in place, you’ll have a professional-grade feature that looks great and performs even better. Now, grab your trowel and get to work!

Jim Boslice
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