Engineering Advantages of VERSA-LOK Retaining Wall Systems

Solid Unit Durability

Solid, high-strength concrete VERSA-LOK units offer superior resistance to damage during construction. VERSA-LOK’s pinned interlock eliminates block protrusions, such as lips, and thin sections that are vulnerable to damage. Solid wall units often are preferred when a parking lot, roadway or body of water is at the base of the wall, because solid units provide improved durability against accidental impacts or flood debris.


Solid VERSA-LOK units are some of the heaviest and most stable units, per wall-face area, in the segmental industry. They are also at least twice as deep as they are high, providing a low, stable center of gravity for each unit during construction and in the finished wall. With proper geogrid soil reinforcement, VERSA-LOK walls can be stable in excess of 50 feet in height. All VERSA-LOK walls, even the random-appearing Mosaic system, have level coursing that easily accommodates geogrid. The setback between courses of units ensures that walls lean back into the soil they are retaining, improving stability.

Agency Approved

Over the last 20 plus years, VERSA-LOK walls have been used or approved by many conservative engineering agencies, including the U.S. Army Corps of Engineers, Federal Highways, and many state Departments of Transportation. VERSA-LOK walls built for agency projects include critical shoreline flood control structures, retention ponds, bridge abutments, road widening walls, erosion control and slope stabilization walls, and tall walls with heavy surcharges. VERSA-LOK walls have also been through extensive reviews to obtain published evaluation reports from the commercial wall ICC Evaluation Service and the transportation agency oriented Highway Innovative Technology Evaluation Center (HITEC).

Cost-Effective Hardscaping Solutions

VERSA-LOK segmental retaining walls cost significantly less than cast-in-place cantilevered walls, big pre-cast blocks, or natural stone walls. For shorter walls, VERSA-LOK walls save money because they do not need structural footings below frost. Geogrid soil reinforcement provides a cost-effective way to stabilize taller VERSA-LOK walls. In fill situations, geogrid can be placed as the fill behind the wall is compacted, at very low additional cost. In cut situations, soil behind the wall must be over-excavated to place geogrid-reinforced soil. However, the excavation needed for geogrid lengths is generally comparable to that needed for deep, structural footings of cast-in-place walls or that needed for big, deep pre-cast units and the drainage aggregate behind them. As a result, the total installed cost of VERSA-LOK geogrid-soil reinforced segmental retaining walls is significantly lower than the material cost alone of large, pre-cast units or cast-in-place structures.


Solid VERSA-LOK units consistently deliver the properties assumed in design, because they do not rely on contractors to fill hollow cores with aggregate. The assumed design weight and the stability of solid VERSA-LOK units are provided consistently, automatically. In addition, with solid units the assumed interlock between units (shear strength) and the interlock of units with geogrid (connection strength) are not subject to variability resulting from contractors filling cores.

Pinned Interlock Advantages

VERSA-Tuff pins are made from a high-end, fiberglass-reinforced nylon that is durable, inert, and does not corrode like steel reinforcement. This pinned interlock eliminates the need for protrusions, lips or tongues, so geogrid can be placed on a flat, uniform unit surface between courses of units. This aids proper installation of geogrid and avoids geogrid damage that can occur when grid is wrapped or bent around a protrusion. VERSA-LOK’s unique hole-to-slot pinning allows variable bond, a structurally preferable installation method, because variable bond eliminates the gaps between units that are necessary with wall systems that require half-bond installation.

Combination Mechanical and Frictional Unit Interlock System

VERSA-LOK’s unique pinning system provides excellent interlock of units and connection to geogrid. While some systems have only one type of connection, VERSA-LOK’s interlock system delivers a premium combination of both a mechanical (pinned) connection and a frictional connection. The mechanical connection insures excellent interlock even when weight on the units is low (during construction and at the top of finished walls), which purely frictional connections do not provide. The frictional portion of interlock between solid VERSA-LOK units is greater lower in the wall, where units bear more weight. The frictional portion of the interlock also evenly distributes loads across the whole connection and maintains good interlock even around curves.

Freeze/Thaw Resistant

VERSA-LOK units are placed on granular leveling pads and are dry-stacked without mortar. This creates a somewhat flexible structure, because the units can move slightly in relation to each other without structural damage to the walls.

Free-Draining Retaining Wall System

Because VERSA-LOK walls are built without mortar, water can pass through the wall joints to help eliminate hydrostatic pressure behind walls. In addition, VERSA-LOK walls easily accommodate other drainage materials in and behind the walls so that water loads can be avoided even in high groundwater environments