Retaining Walls in Mountainous Terrains
Retaining walls provide a pleasing aesthetic to landscapes and double as a functional solution for slope and erosion problems. Effective in the mountainous terrain of Western North Carolina, they assist in leveling yards, creating planting beds, and alleviating erosion.
Of the many alternatives available to retain earth, in our opinion, drystone retaining walls are always the most beautiful! A properly built drystone wall can last for decades if not centuries. In engineering terms, a drystone wall is a gravity wall, which means that its mass and weight are what keep it and the earth behind it in place. Because drystone walls contain no mortar or concrete, water can drain through the entire face of the wall. This eliminates common issues caused by hydrostatic pressure, or the force that can push over mortared stone walls. Read here about a mortared wall Hammerhead repaired after hydrostatic pressure caused a blowout. Building dry is the way to go!
Construction of Retaining Walls
Essential to the function of retaining walls is proper construction and the inclusion of a batter to its face. This refers to the slightly backward tilt of the front of the wall. Further, it must be deep enough to accommodate the load it is bearing.
One of the most common mistakes made when constructing drystone walls is making them too thin. When small stones in a single layer are used against soft ground, the wall is too thin, and it will inevitably fall.
Proper bonding is also a crucial component in drystone wall construction. In masonry, bonding does not refer to sticking or gluing, but rather to the stacking principle of “one-over-two, two-over-one.” A well stacked drystone wall is a complex web of forces and interactions that makes the whole substantially stronger than the individual pieces. A good stone wall is a community organized to solve a problem, the goal being to ensure that problem-solving ability for years to come.
Click here to discover one of favorite materials for constructing retaining walls – granitic gneiss.