To build a drystone wall, horizontal rows of stones are placed one atop the other.
The stones have two visible faces connected by a filler of rubble called reble, which acts as a support and stops the outer stones from moving.
Both faces are built simultaneously, forming the body of the wall in parallel, which is built up with stones in a decreasing order of size. The final row on the body of the wall, the igualada, forms a horizontal line and consists of small stones.
To seal the wall, a finish is needed to stabilise the work as a whole. This finish may be completed in drystone, using rectangular cobertores or flat, heavy slabs. In other cases, a sand and lime mortar is applied, either to repoint the slabs, or to create a coping, the tàpia, in a half-round or esquena d’ase (donkey-back) shape, which is whitewashed. This finish seals the work, acting like a strengthening beam.
The walls are never built absolutely vertically. The width of their base is always greater than the crown. The iron rods acting as a construction guide are driven into the ground at a certain angle known as the peu or tumbada. The result is that the wall’s section is never rectangular, rather resembling the shape of a truncated pyramid. The stones are positioned at an angle inwards, and must touch each other.