Like the name suggests, stackable retaining walls are made by simply stacking blocks together ... dig a trench that is about 4 to 6 inches deep and 12 inches wide. The rule of thumb is you ...

Concrete block is a popular type of material for retaining walls due to its durability and flexibility. Concrete blocks range from basic 12-inch by 6-inch units ($4 to $7 per unit) to more ...