History of Dry Stone Construction
Stone is one of the oldest construction materials known to man. The most ancient remaining drystone structures are scattered throughout the world, with Egyptian pyramids and Peruvian temples as world-class examples. Prehistoric dwellings - brochs, bories, trullis, cabanes, cleits, and giren - extend from the Shetland Islands to the eastern Mediterranean. Drystone terraces and canals built to aid agriculture around the world are equally ancient and widespread.
Since colonial times, the United States has built upon a rich drystone heritage. Agriculture, industry, and roadways developed over 200 years using native stone on a vast scale. On farms, there were drystone dwelling houses, barns, slave quarters, spring houses, smoke houses, and ice houses. Towns contained stone court houses, clerk’s offices, banks, shops, inns, and churches. Structures for transportation and early industry include drystone mills, dams, bridges, stream and pond borders, iron furnaces, lime kilns, and distilleries. Many unnoticed drystone structures still support daily use: retaining walls at stream banks and road cuts, railway piers and embankments, and bridge piers and abutments. Today, the most widely-recognized historic drystone structures are the stone walls and rock fences that border fields, pastures, and roadways in regions of the country where building stone was readily available.
Dry stone masonry has been a successful building technique throughout the ages because of its unique range of benefits. It can provide good employment for craftsmen without working capital for heavy equipment. Masons need a minimum of tools to erect structures that are remarkably durable; yet, if damaged, are easily repaired. They resist fire, water, and insects. If correctly designed, they are earthquake resistant. The work does not deplete natural resources, and aesthetically compliments and enhances the landscape.
Dry stone structures have many advantages over mortared walls. Walls without mortar rely on the skill of the craftsmen and the forces of gravity and frictional resistance. They have a slight flexibility that allows them to conform to foundation settlement without damage. Because the sides slope slightly inward, ground movement locks the structure more tightly together. Importantly, a stiff concrete footing is not needed, saving labor and material expense.
Mortared walls have a shorter life span than drystone walls because frozen rain and snow get trapped in mortared seams and push the joints apart, whereas a correctly-built drystone wall drains naturally without damage. Accidents to mortared walls tend to break out large sections, making damage-repairs costly. Mortared walls also cost more to repair because mortared rock is not easily recyclable, requiring additional new material.
Lack of information and expertise cause many architects, engineers, and builders to depend on finite answers to their building needs. It is a goal of the Dry Stone Conservancy to re-establish the preeminence of dry stone as a viable, preferred construction method.