About five kilometers west of Jerusalem, archaeologists have found something remarkable: over 100 plastered floors dating back to 7100-6700 BCE. These floors are roughly 9,000 years old, which is long before the Romans, who were traditionally credited with inventing this technique.
The site is called Motza. According to a study published in 2026 in the Journal of Archaeological Science, the ancient residents were making lime plaster from dolomite, a rock containing both calcium and magnesium carbonate. This is the same method the Roman architect Vitruvius described in the first century BCE.
Lime plaster is made by heating stone in fire until it releases carbon dioxide, then adding water to create a paste that hardens as it reabsorbs carbon dioxide. However, dolomite is difficult to work with. The temperature must stay below roughly 900 degrees Celsius, or the dolomite is destroyed.
Excavations between 2015 and 2021 revealed separate fire pits for burning limestone and dolomite side by side. This shows the residents understood these were different materials requiring different treatment. Dolomite burns at a lower temperature than limestone, saving fuel, and produces stronger, more water-resistant plaster.
The most striking evidence came from the plaster chemistry itself. The dolomite had fully recrystallized, something so difficult that it had only been seen in laboratories before. The Motza residents achieved this in their homes, walking on these red-painted floors daily. They solved one of the hardest problems in early construction thousands of years before the Romans.