Why Dry-Stone on Ligurian Slopes
The Ligurian Apennines drop sharply toward the sea in a series of narrow valleys and ridgelines. Usable flat ground is scarce, and the soils that do exist tend to wash down in winter rain. To hold both soil and water on cultivable ledges, builders cut horizontal terraces — known locally as fasce — into the hillside and retained each ledge with a stone wall built from the material displaced during cutting.
Because lime was expensive and difficult to transport to remote upland sites, and because the schist and sandstone of the region fractures into flat-faced pieces suited to coursed construction, mortar-free walls became the default. A well-laid dry-stone wall can flex slightly when the ground moves — an advantage in an area with occasional seismic activity — whereas a rigid mortared wall may crack and fail suddenly.
Site Reading Before Construction
Before any stone is moved, experienced builders examine the slope for:
- Soil depth — shallow soils over bedrock require different terrace widths than deep clay soils
- Water movement — identifying where runoff collects during heavy rain determines where drainage channels must be integrated into the wall base
- Rock type and availability — the local schist and grey limestone of central Liguria behave differently; schist splits into thinner slabs suitable for tight coursing, limestone tends toward blockier pieces better suited to foundation courses
- Existing vegetation and root systems — olive and fig roots can destabilise poorly built walls if not accounted for at the design stage
Foundation and Base Course
The lowest course of a terrace wall is set into a shallow trench cut into the natural slope. The trench depth depends on the anticipated load: a low wall retaining a narrow terrace might sit on a single below-grade course, while a wall over a metre tall requires two or more buried courses to resist the outward pressure of saturated soil in winter.
Foundation stones are the largest available pieces. They are placed on a level bed of compacted subsoil or, where the slope is prone to movement, on a thin layer of rammed gravel that allows slight drainage. The critical rule at this stage is that each foundation stone must rest solidly on three points of contact with the ground or the stone below. A rocking foundation stone will eventually cause the entire wall above it to shift.
"The base is where you spend your time. The face looks after itself if the base is right."
— Recorded by the Cinque Terre National Park restoration programme, participant documentation, 2019
Building Up: Coursing and Tie-Stones
Above the foundation, stones are laid in roughly horizontal courses with a slight backward lean — a batter — into the hillside. For a wall retaining a metre of soil, a batter of around 1:6 (one unit back for every six units of height) is common in Liguria. Steeper batters are used on walls retaining deeper fills or wetter soils.
Every 40 to 60 centimetres of wall height, through-stones (tie-stones or diatoni) are placed. These run the full depth of the wall, binding the two faces together and preventing them from separating under soil pressure. In a 50-centimetre wall, a through-stone spans the entire width; in a thicker wall, paired through-stones are staggered.
Vertical joints must never stack directly above each other on consecutive courses. This rule — that each stone bridges the joint below it — is the single most consistent principle in Ligurian dry-stone construction, and its observance distinguishes sound walls from those likely to fail within a decade.
Fill and Drainage
The space between the wall face and the uphill slope is not simply filled with soil. A zone of angular stone rubble — typically 10 to 20 centimetres thick — is placed directly behind the wall before any soil is added. This free-draining layer allows water to move downward through the wall base rather than building up as hydrostatic pressure against the face.
At intervals along the base, gaps are left between foundation stones or small drainage pipes of hollow terracotta are set in. These weep holes prevent water from pooling at the back of the wall during sustained rain. In older Ligurian walls, the gap between two adjacent foundation stones, sometimes shaped into a small arch, served this function without additional materials.
Coping
The top course of the wall — the coping — is made from flat, wide stones set on edge or laid flat with their longest dimension running across the wall. Coping stones protect the wall body from erosion by rain falling directly on the top and from foot traffic along the terrace edge. In Liguria, coping stones are often the most carefully selected pieces in the entire wall: wide enough to span the top width, thick enough to resist splitting, and set tightly to prevent displacement by frost.
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