Armour stone retaining walls provide a strong, natural-looking way to manage grade changes and create more usable space within a landscape. Their large size and irregular texture make them especially well suited to sloped properties, multi-level backyards and projects where the retaining wall should become a visible landscape feature.
However, armour stone is not the right material for every wall. The design, site access, drainage, soil conditions and available space all need to be considered before construction begins.
What Is Armour Stone?
Armour stone consists of large pieces of natural stone selected and placed to create a stable retaining wall. Individual stones vary in colour, texture, thickness and shape, which gives the finished wall a substantial, organic appearance.
Unlike manufactured segmental wall blocks, armour stone does not create a perfectly uniform pattern. The installer must select and position each piece carefully so the stones fit together, maintain the required setback and create a consistent finished wall.
The stone is commonly used for:
- Sloped backyards
- Large grade changes
- Raised patios and outdoor-living areas
- Garden terraces
- Properties with natural surroundings
- Pool and landscape projects
- Steps and transitions between elevations
- Shoreline or erosion-control applications where permitted and appropriately designed
Armour Stone vs. Segmental Retaining Walls
Armour stone and segmental retaining-wall systems can both produce durable walls, but they create very different results.
| Consideration | Armour Stone | Segmental Wall |
|---|---|---|
| Appearance | Natural and substantial | Clean and consistent |
| Shape | Irregular natural stone | Manufactured uniform blocks |
| Space required | Often requires more depth | Can suit tighter layouts |
| Installation | Each stone is individually selected and placed | Installed in engineered courses |
| Design style | Organic and informal | Refined and structured |
| Best suited to | Larger landscapes and natural grade changes | Patios, gardens and more defined spaces |
Armour stone often works best when there is enough room for the scale of the material. A manufactured wall system may be more appropriate beside a narrow walkway, small patio or property line where space is limited.
The decision should be based on the site—not simply which material looks better in a photograph.
Where Armour Stone Retaining Walls Work Well
Creating usable space on a slope
A retaining wall can divide a steep or uneven property into more functional levels. This may create space for a patio, lawn, garden or access route that would otherwise be difficult to use.
Supporting patios and pool areas
Armour stone can help support elevation changes around a raised patio or pool area. The wall, drainage, patio base and pool construction must be coordinated so the different elements work together.
Building garden terraces
Lower armour stone walls can create natural-looking planting areas and divide a slope into manageable sections. Planting can soften the stone and help the wall feel integrated with the surrounding landscape.
Connecting different elevations
Armour stone steps can be incorporated into the wall to connect upper and lower areas of the property. Step dimensions, landings, lighting and adjacent surfaces must be planned carefully for safe, comfortable movement.
Framing outdoor-living areas
The scale and texture of armour stone can create a strong backdrop for patios, fire features and seating areas. In some designs, lower stones may also provide informal seating.
What Determines the Cost?
Armour stone retaining walls are priced according to the entire construction process—not simply the amount of visible stone.
Major cost factors include:
- Wall length and height
- Quantity and size of stone
- Excavation requirements
- Soil and groundwater conditions
- Access for excavators and lifting equipment
- Removal of existing materials
- Base preparation
- Drainage requirements
- Engineering or permit requirements
- Steps, corners and transitions
- Grading and restoration
- Connections to patios, pools or other structures
Access can have a significant effect on cost. Armour stone is heavy and requires suitable equipment for delivery and placement. A wall that is easy to reach from a driveway will generally be more straightforward than one located behind a house with restricted access.
A proper quote should describe the excavation, base, drainage, stone placement and finishing work—not just provide a price per stone.
Why Base Preparation Matters
The visible stone is only part of the retaining wall. Its performance depends heavily on what is underneath and behind it.
The base must be excavated to suitable material, prepared at the correct elevation and compacted to provide consistent support. If the base settles unevenly, the stones can shift and the finished wall may lose its alignment.
The wall design must also account for:
- Existing soil conditions
- Wall height
- Slope above and below the wall
- Nearby structures
- Additional weight from patios, driveways or pools
- Water movement
- Frost and seasonal ground conditions
Reducing excavation or base preparation to lower the initial price can create expensive problems later.
Drainage Behind an Armour Stone Wall
Water pressure is one of the most important considerations in retaining-wall construction.
A properly planned wall may include free-draining material, filter fabric and drainage pipe to help prevent water from building up behind the stone. The surrounding property must also be graded so surface water moves in an appropriate direction.
Drainage should be planned as part of the entire landscape. Water should not be redirected toward a neighbouring property, building foundation, patio or other vulnerable area.
Signs of drainage problems can include:
- Water flowing through the wall
- Soil washing out between stones
- Persistent wet areas
- Movement or rotation of stones
- Settlement above the wall
- Ice accumulation during winter
The correct drainage approach depends on the site, wall and surrounding landscape.
How Armour Stone Walls Are Installed
Construction generally involves the following stages:
Site preparation and excavation
The work area is cleared and excavated to the required depth and dimensions. Existing soil or failed wall material may need to be removed from the property.
Base installation
A compacted aggregate base is installed to create stable, level support for the first course of stone.
Stone selection and placement
Each stone is lifted into position using suitable equipment. The installer checks its bearing surface, elevation, alignment and relationship to adjacent stones.
Drainage and backfilling
Drainage materials are installed as required, and the area behind the wall is backfilled in controlled stages.
Grading and finishing
The surrounding grades are completed so water is managed properly and the wall connects cleanly with lawns, gardens, patios, steps or walkways.
Larger or more complex walls may require professional design, engineering or municipal approval. Requirements vary by municipality and property, so they should be confirmed during planning.
How Long Does an Armour Stone Wall Last?
A properly designed and installed armour stone wall can provide long service because the stone itself is highly durable. The more common causes of failure involve the construction around the stone rather than the stone material.
Potential problems include:
- Inadequate base preparation
- Poor drainage
- Unsuitable soil
- Incorrect stone placement
- Excessive loads above the wall
- Unplanned changes to surrounding grades
- Erosion or loss of backfill
Natural weathering and colour variation are normal. Individual stones may develop surface marks or minor changes in appearance without affecting the wall’s performance.
Maintaining an Armour Stone Wall
Armour stone generally requires limited routine maintenance, but the wall and surrounding grades should still be observed over time.
Watch for:
- New gaps or movement
- Settlement above the wall
- Soil washing through joints
- Blocked drainage outlets
- Water collecting near the wall
- Tree roots or large plants affecting the structure
Avoid changing the grade, adding heavy structures or directing downspouts toward the wall without first considering how the change may affect drainage and loading.
Planning an Armour Stone Retaining Wall
A successful armour stone wall must suit the property structurally and visually. Stone size, access, base preparation, drainage, grading and nearby landscape features should all be considered before construction begins.
Earthworks Landscaping & Pools designs and installs armour stone and segmental retaining walls as part of complete landscape projects. We coordinate the wall with patios, steps, grading, drainage, pools and surrounding landscaping so it functions as part of the whole property.
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