Venetian Plaster in Ancient Times
Lime Plaster is used for decoration since the end of the eighth millennium BC. Lime plaster is composed of hydrated lime, sand and water but traditional lime plaster also contained
horse hair to reinforce it. It was used for building purposes in ancient Egypt, Malta and China and some of these architectural wonders can still be seen today.
Traditionally, Venetian Plaster is lime based and made of slaked lime and marble dust. Vitruvius,
the great Roman architect was the first to write about Venetian Plaster in his book "De Architectura" (De Architectura libri decem) in the 1st century B.C. The Romans used a number of thick
layers, sometimes as many as ten to create a smooth, compact and even surface. Sometimes they added terracotta granulate to the Plaster of Paris, which, being porous could absorb a greater amount of
the sluble salt contained in damp walls. The idea of adding different materials to lime plaster to enhance some of it`s attributes came from Opus Signum or CoccioPesto, which is a
material made of tiles (sometimes pottery) broken up into very small pieces, mixed with mortar, and then beaten down with a rammer. Opus Signum (fine roman concrete) is so solid that you can
still see it at the Welwyn roman baths or the the Wearmouth-Jarrow monastery.
Vitruvius described the seven step process of Marmoratum
Opus (meaning marble capable of taking a high polish) but
it was Pliny the Elder in his Naturalis Historia (Books XXXIII–XXXVII) who expanded on Vitruvius' work and wrote of the Roman's method of slaking limestone, keeping it in covered pits and in
dark cellars for three years. The maturing of the limestone was a secret process and the final product was considered much like fine wine. The reason of the process was to prevent the carbonation
which would reduce the causticity, binding, and hardening nature of the polished plaster. Pliny the Elder (who also provided us with the most comprehensive information regarding the creation of
mosaic art) was convinced that ancient stuccos were superior because of the length of time the lime putty was matured and because of the time dedicated to chopping and beating
It can be said that Venetian Plaster fulfills the requirements of the Vitruvian
Triad of firmitas, utilitas, venustas –
that is, it must be solid, useful, beautiful.