Engineers and installers often wonder whether a concrete leveling pad may be superior to gravel. While a rigid foundation isn’t what we’d typically recommend, it can be used provided the engineer okays it. Unlike gravel, however, this footing may crack and break apart as the wall shifts with moisture and temperature changes. Concrete will also be more expensive and typically add to labor, so it should be avoided in most applications. If an existing concrete footing must be used, then the bottom course of block must be tied to the footing using steel rods. This eliminates concerns of potential sliding of the wall.
Most Allan Block walls are designed with a gravel base which is a minimum of 6 inches in depth, and 2 feet in width (15cm and 60cm). There are benefits to using this type of footing. One major benefit in cold climates is that gravel is not negatively impacted by movement caused by freeze-thaw. To learn more about our recommended base, visit the base installation guide.