Dry Stone Retaining Walls

With the help of NCPTT grants, the Dry Stone Conservancy recently released two training videos focused on preserving dry stone structures, craft, and history.

The first of these, a training video entitled How to Build Dry Stone Retaining Walls, (NCPTT product 2001-11) shows how to build or repair small dry stone retaining walls from beginning to end: laying out the shape, digging the foundation, setting the wall angle, building the face, packing the back, and leveling the top.

The techniques are suitable for all rock types, whether glacially rounded, angular, or flatbedded. A series of graphic drawings illustrate the principles of retaining wall construction followed by two case studies showing on-site training classes.

One project depicted is a low, two-foot wall taught by a master craftsman who discusses plans as well as problems the class members encounter and solve. The second project is a four-foot wall that supports an equestrian trail and traverses a wet-weather water course in a Louisville park. This video is designed to assist craftsmen, engineers, architects, landscape architects, federal and state parks personnel, and private landowners responsible for the preservation of drystone retaining walls.

The second video, Retaining America's Dry Stone Heritage: Preserving Dry Stone Walls in the Chesapeake and Ohio Canal, (NCPTT product 2001-12) documents the repair of damaged canal walls in the popular C&O Canal National Historical Park.

At Harpers Ferry, the canal, highway, and railroad all share the same narrow space where the Potomac and Shenandoah Rivers cut through the Blue Ridge. After 150 years, the 1996 floodwaters, channeled forcefully through this passage, damaged the old canal walls. Downstream, at Washington, large tree roots had grown through the dry stone masonry, and heavy industrial warehouses built too close to the canal, damaged dry stone walls there. This video is the story of those repairs. The footage depicts the planning and organization essential for a large-scale restoration project. It shows the use of modern equipment-replacing donkey power, pulleys, and wenches - lifting the irregular, awkward, and extremely heavy schist and gneiss boulders back into place. There is no mortar or concrete. The venture emphasizes the Park Service's philosophy of authentic preservation and serves as a prototype for future genuine repairs.

Projects in both videos were organized and managed by the Dry Stone Conservancy. For instructions in print, the DSC handbook Building and Repairing Dry Stone Fences and Retaining Walls contains sectional drawings of retaining walls.