Opus incertum ("irregular work") was an ancient Roman construction technique, using irregularly shaped and randomly placed uncut stones or fist-sized tuff blocks inserted in a core of opus caementicium.

Opus reticulatum (“reticulate work”) is a technique that employs diamond-shaped pieces of tufo known as cubilia that are placed within a core of concrete. The resulting pattern of the flat ends of these blocks form the net-shaped pattern that lends its name to the technique.

Mar 19, 2020 · The oldest form of this technique was the so-called Opus incertum, introduced around the end of the 3rd century BC, which used small pyramidal blocks that were placed outside the wall and which...

Mar 9, 2025 · Roman concrete construction was categorized by its facing, with three primary types: opus incertum, opus reticulatum, and opus testaceum. In all three methods, concrete was poured between two layers of facing material, with walls typically measuring two to three feet (±0.6-0.9m) thick.

Opus incertum (“irregular work”) is an early concrete technique that emerged during the earlier second century B.C.E. and continued in use until the middle of the first century B.C.E., gradually abandoned in favor of opus reticulatum.

Oct 24, 2024 · Opus Incertum was a flexible and economical wall construction technique utilizing irregularly shaped stones set into a core of concrete. This method was commonly used for less visible or less critical structures, such as inner walls or retaining walls.

One of the first ways of using this concrete core involved a construction technique called opus incertum: randomly inserting irregularly shaped, uncut stones and/or small tufa blocks into the concrete.

Small, irregular blocks inserted into thick mortar to create a crude masonry surface to a rubble or concrete wall. It appears in Roman Republican architecture, certainly by the 3rd or 2nd century bc at Ostia, and perhaps earlier (see Architecture,). [...] From: Opus Incertum in The Grove Encyclopedia of Classical Art and Architecture »

Call for Papers: ‘Facciate Parlanti’, Opus Incertum, Issue 8 (2022), Deadline: June 30th, 2021 Since antiquity buildings have carried inscriptions on their surface. In particular, the habit of decorating façades with epigraphs spread in early modern Europe in …

Opus incertum was the most common facing for ordinary concrete walls of the 2nd and 1st centuries BC. The face of the concrete was studded with three- to four-inch irregularly shaped pieces of stone, usually tuff.