ashlar

Ashlar is finely dressed stone that has been cut into blocks with precise faces and edges, designed to fit together with tight, regular joints. The term applies to both the individual blocks and the masonry built from them. Ashlar masonry contrasts with rubble or fieldstone construction, which uses irregular stones without uniform faces.

Blocks are typically squared on at least two faces and often planed on several sides. They are laid in horizontal courses with regular joints, sometimes in a uniform bed and cross-joints. In coursed ashlar, stones are cut to uniform sizes and arranged in horizontal rows; in random or non-coursed ashlar, widths vary but the stones remain dressed and aligned. Some variants use polygonal or curved faces to accommodate irregular architecture, while still relying on dressed stone.

Ashlar blocks are commonly made from durable stone such as limestone, sandstone, granite, or marble, and may be polished, rusticated, or finished smooth. The technique requires skilled quarrying and masonry work, making ashlar masonry relatively expensive but yielding walls with refined appearance, high dimensional accuracy, and good durability.

Historically, ashlar has been used for monumental and sacred buildings as well as façades and structural walls in many cultures, from ancient Greece and Rome to medieval Europe and later architectural traditions. In modern construction, ashlar-inspired finishing stones or precut blocks are used for decorative or structural purposes, preserving the technique’s characteristic precision and aesthetic.