In 2001, there were just under 2,000 searches a month on Yahoo for 'Venetian plaster' and a whopping 8,000 per month for 'faux finish.' In January 2006, there were about 12,000 searches for 'Venetian plaster,' compared to still about 8,000 for 'faux finish.' What is the reason for this newfound popularity?
Today you say 'Venetian plaster' and just about everyone has an idea of what it is, in part because of the DIY programs on TV. Most people still think it is just a paint that you trowel on, something any homeowner can do. Some people add caulking to sheetrock mud and call it Venetian plaster. Every paint store has come out with what they call Venetian plaster. Everyone is jumping on the bandwagon.
I had a chemist call me two months ago. He had been working for an undisclosed client, trying to reproduce a lime Venetian plaster here in the States. He told me he could get the plaster to look the same and smell the same, but when he put it on a wall, the final look was not the same. 'There is something magical about the limestone from Italy,' he said. He said he hated to admit defeat, but he was going to call his client and tell them what they were asking him to do was impossible.
So what makes Italian plasters unique? Well, let's look at the history of the plasters. Venetian plasters were composed of mainly lime grassellos, hydrated lime blended with marble powder (calcium carbonates) and organic substances. Keep in mind that the plasters were not just for looks. They were used to protect the structure, which was made of brick and stone.
The first examples of plasters can be identified with blends of mud and clay, frequently modified with vegetable materials like leaves, straw or animal dung. By the time of the Greeks and the Romans, plaster was composed of a number between four and seven different layers. Today the usual habit is three layers, on top of which decoration is created.
After the brick and stone, they would start off with the 'rinzaffo' coat, composed of a blend of cement, hydraulic lime and coarse sand (approximately 2 mm to 8 mm). The next coat, the 'arriccio,' composed of mid-sized sand (0.6 mm to 2 mm) blended with hydraulic lime and hydrated lime. The next two coats were lime and fine sand, and the three final coats were lime and marble dust. According to the grain size of the filler (marble powder), they would accomplish different effects. A grassello would be more like marble flour and would have a very high shine. Marmorino, which means 'little marble,' would have more of a satin finish.
The limestone was slaked in big open pits for months. The longer lime is slaked, the better it is. But the slaking of the lime is not the only thing that makes it different. As the chemist pointed out, the limestone available in the States 'had a different quality in it.' It had a different composition than Italian lime.
From the Egyptians to the Romans, plaster did not change much. Each applicator would put his different twist on making plasters, but all were basically the same. However, Venice, which gave Venetian plaster its name, was built on stilts. The walls could not take the weight of real marble, so plasters were used to decorate instead. By adding earth pigments to the plasters, the Venetians could achieve many looks. When I was at the Palazzo Ducale in Mantua, I saw where they added the tint to the plaster while on the trowel and then put it on the wall. This was done only in panels, because it was very hard to control.
Every time I complete a Venetian plaster job, my clients are getting a piece of Italian history that will last longer than their taste in colors. The feel, the look, cannot be reproduced by paints and glazes.