Engineered retaining walls to control slope, prevent erosion, and improve the structure of your outdoor space.
Retaining walls serve both structural and aesthetic purposes, transforming unusable slopes into tiered, functional landscape areas. In Montreal, where clay-heavy soils expand and contract dramatically with moisture and frost, proper wall construction is critical. Our process begins with a site evaluation to determine soil type, slope angle, water table level, and the total height of earth to be retained. For walls under four feet, we use gravity-based segmental block systems from manufacturers like Permacon or Allan Block that rely on their own mass and setback for stability. Walls over four feet require geogrid reinforcement -- layers of high-strength polyester mesh anchored into the compacted backfill at specified intervals to resist the lateral earth pressure. We always install a drainage core behind the wall face using clear stone wrapped in filter fabric, connected to a perforated pipe at the base that daylight to a discharge point. This prevents hydrostatic pressure buildup, which is the number one cause of retaining wall failure. Material choices include textured concrete block in a range of earth tones, natural stone like Laurentian granite for a premium rustic look, and armour stone boulders for larger-scale retention. We set walls on a compacted granular footing buried below the frost line -- at least four feet in the Montreal region. For walls that also serve as seating or border elevated patios, we add cap stones with a smooth bullnose finish.
Why this service
Slope and erosion control
Structural durability
Improved curb appeal
FAQ for this service
How tall can a retaining wall be without an engineer?
In most Quebec municipalities, retaining walls up to four feet (1.2 meters) can be built without a structural engineer. Walls exceeding this height require engineered drawings that specify geogrid placement, base dimensions, and drainage details. We work with licensed engineers when required and include this coordination in our project management.
What causes retaining walls to lean or fail?
The most common causes are inadequate drainage behind the wall, insufficient base depth, and lack of geogrid reinforcement for taller walls. Water trapped behind the wall freezes in winter and expands, pushing the wall forward. Our installations always include a full drainage core and frost-depth footings to prevent these failures.
Can a failing retaining wall be repaired or does it need full replacement?
It depends on the severity. Minor leaning or settlement in the top courses can sometimes be corrected by dismantling the affected section, improving the base and drainage, and rebuilding. However, walls with significant bowing, cracked blocks, or foundation failure typically need complete replacement to ensure long-term structural integrity.
