The craft of dry stone walling, which means building in stone without mortar or cement, must be very old. How old we do not know. The prehistoric drystone builders could assemble a roof in the shape of a set of long stones, on very narrow chambers. Before the advent of mortar, they employed their skills to erect such basic shelters as well as mausoleums and open air temples. Later as agriculture and animal husbandry developed, so did work in dry stone. Dry stone features such as ramps and terraced retaining walls made – and continue to make food production sustainable in hilly and mountainous areas. Freestanding dry stone walls were built high enough to be termed “stockproof” – serving to protect the livestock from predators .
A properly built dry stone retaining wall must be built in a “freestanding” mode . That is to say this : it must stand up completely and entirely on it’s own merit while being built. The unfortunate and all-too-common practice of throwing soil, stone and random material hodge-podge behind a wall – while building up – in a wishful attempt to hold it all temporarily together before throwing in more backfill – is dead wrong .
The opposing 2 “faces” of a freestanding wall are tied together in an interlocking & overlapping placement of material . The same principles applied to building a freestanding wall apply to building a retaining wall . However , the “back wall” of a retaining wall is buried and thus, since that face will not be seen , it need not have a crisp flush face . The area behind the back wall may be filled with stone, then compacted to further buttress the construction and provide drainage .
Structural elements such as batter, protruding foundations, thorough “hearting”, tie stones and capitals will fortify and extend the life of the construction. Built to stand on its own – it will need little maintenance over its life and will serve for many centuries.