The Maximum Height of a Stacked Stone Retaining Wall

Maximum Height

• Retaining walls made from stacked stone should be no higher than 5 feet, according to the University of Minnesota. The University of Nebraska-Lincoln recommends 3 to 4 feet as the maximum height. Stacked stone walls do not use cement to secure the individual stones and building them higher may cause them to become unstable.

Foundation

• How high you can build a stacked wall depends, in part, on the foundation you provide. A concrete footing is necessary for building walls higher than 4 feet. The width of the footing should be one-fifth the overall height of the wall and should sit 24 inches below ground. For shorter walls, tamp the soil down 12 to 18 inches to form a hard, solid base. Lay the largest rocks as the base, setting them 2 inches to 8 inches beneath the soil surface.

Design

• The wall design also influences stability and the height you can safely build the wall. Gently curving lines are usually more stable than a straight wall. Ensure that each rock fits snugly before adding more rock and use larger, wider rocks at the base of the wall. Improper drainage may cause a retaining wall to fail. Before backfilling the area with soil, add gravel or drainage pipes so water pressure does not build up against the wall.

Solutions

• To retain the soil on a steep slope, build several smaller retaining walls instead of one high wall. Another option is to build a concrete structural wall with concrete reinforcement between the stones, rather than a dry-laid stacked wall.