MARMORINO

MARMORINO - A noble finish with endless meanings

By Prof. Vanni Tiozzo
Professor in Restoration work
at the Fine Arts Academy in Venice

The Ancora trademark has always been synonymous with quality and Made in Italy.
Pavan Ernesto & Figli S.p.A., is a firm with deeply entrenched roots in the past, which invests a great deal in research to cast a safe “anchor”, a foothold for professional craftsmen.
The factory is situated next to the old square in Arcade, just a few miles from Treviso, where, back in 1716, documents already testified the artisan activities of the Pavan family. After the war, it was transformed from an artisan workshop to an industrial enterprise, which, in three generations, has gained a leading position in supplying the building trade both at home and abroad, mainly in Europe, America, Asia and Oceania.
Each single article produced by Pavan is meticulously controlled and is the result of the production philosophy that constantly aims at satisfying the needs of professional craftsmen.

The Ancora trademark by Pavan Ernesto & Figli S.p.A., would like to take you on a journey back in time to discover the origins of decorative plastering.
The beautiful applications on the walls of the most famous Venetian villas, but several modern homes too, bear a historic wealth that only a few experts can fully understand.
Prof. Vanni Tiozzo, Professor in Restoration Work at the Fine Arts Academy in Venice, will guide us in our search back in history to discover the noble origins of marmorino in the splendour of the Venetian Republic which, in turn, is witness to the knowing techniques used in ancient Rome.
The materials and techniques have changed over the years, as knowledge and expertise gave grown and to adapt to the changing climatic and environmental factors.
The story of the art of marmorino is woven with that of Venetian stucco and the more recent smooth plaster, the similarities and differences of which are explained in detail in this brochure.
These finishes give such a smart and refined appearance to the building that they are considered almost on par with pictorial-art.
This is why we wanted to dedicate a moment of reflection to all those professional craftsmen who use our tools, to give them the confirmation of the enormous value of their work.

Pavan Ernesto & Figli S.p.A

“Marmorino” (which literally means little marble) is a very complex term and includes numerous different meanings that witness all the changes that have taken place in its composition over the years.
Marmorino is, first and foremost, plaster, i.e. something that covers the buildings but besides physically protecting the walls from infiltration, it is also like an attractive dress that is worn to give the building that special desired appearance, no matter what materials are effectively used.
Plaster is a layer that covers the surfaces of the buildings and, depending on how uneven the walls are,  is applied using one or more layers formed of a binder and various types of aggregates. The binder is usually lime, what is now called lime paste or slaked lime putty; once it is dry it forms a layer of artificial stone, which is extremely stable, breathable and durable, resistant to any sort of weather.
Slaked lime putty is made by cooking limestone which forms calcium oxide or unslaked lime; it is then transformed, which means treating the unslaked lime with an amount of water that is two and a half times its weight, to form the hydrated lime, that is calcium hydroxide or lime paste or slaked lime putty. Its quality is measured by its fineness and tackiness, because it must stick like glue to the trowel blade.
The drying process for the lime putty is called ‘carbonating’, because exposure to the carbon dioxide in the air transforms the calcium hydroxide into calcium carbonate, i.e. carbonate stone like, for example, Istria stone. This drying phase is very delicate however, for the correct evaporation of the enormous amount of water in the putty, and the type of aggregate used and the process are of great importance.
The most common aggregate is sand because it is stable, easy to find and economic, but it does not have a binding function only stabilising. Putty with too much sand would cause shrinkage cracks that would make the finish unstable and excess sand would make the layers flaky. The normal ratio in plaster is three parts of sand to one part of lime paste.
Replacing sand with marble powder creates marmorino, a white putty without the black spots typical of sand, which, besides being very even, when it is dry is entirely formed of calcium carbonate and is, therefore, artificial stone. Calcium carbonate has a macro “crystalline” morphology however, which gives exceptional gloss and brilliance to the plastered surface, and marmorino is the perfect solution to simulate a stone building.
Marmorino was already used back in Roman times to coat the buildings, and Vitruvio wrote of it in the 1st century B.C. in his work “De Architectura”; at that time, marmorino was formed of a number of thick layers which often reached 10 centimetres in all, creating a smooth, compact and flat surface. Sometimes the layers were formed of lime and terracotta granules which, being porous, were able to absorb a greater amount of the soluble salts contained in the damp walls. This sort of application required a considerable work force and organisation, as it was a very strenuous job to compact the aggregate and to draw the water from the putty through to the surface.
In medieval times, the use of plaster with marble powder was very limited, mainly used for coating the walls that were then fresco decorated, and mainly in the northern Adriatic region, perhaps owing its origins to the East Roman Empire. The way work was organised did not permit complicated processes, therefore just a single layer was applied, two or three millimetres thick, with a smoothed and slightly undulating surface, to create a white surface like a canvas waiting to be painted.
Only with the Renaissance period was marmorino rediscovered, as part of the more general attention that was paid to the classic cultures. Around the end of the 15th century, a series of constructions were built that tried to copy Roman architecture, with a simple smooth surface of lime and marble powder, on a sand based plaster, which is now called lime finish with spatula effect, then applied with a trowel, which slowly took on its original form of marmorino  by adding the layer of terracotta granules. This smart finish characterised a great deal of Venetian architecture during the Renaissance period, embellishing the façades overlooking the Grand Canal, giving them the appearance of Istria stone, like the walls on many other less important buildings in other historic Veneto towns. Marmorino also characterises the lovely architectural work of some great Veneto artists, like Jacopo Tatti, called Sansovino, Andrea di Pietro dalla Gondola, called Palladio, Vincenzo Scamozzi and many others. Buildings like the Procuratie Nuove, the churches of St. George and the Redentore in Venice, the Veneto villas of Malcontenta, Maser and Rotonda, St. Mark’s Loggia in Venice, are all appreciated throughout the world for their precious finish. A finish that simulates noble stone, like, for example the Diamond Palace in Ferrara, where the stone covered part reaches the second floor, and from there the plastering imitates the effect of the stone – a ploy that characterises a lot of buildings of that time. However, several marmorino applications are rather fine, showing the undulating surface beneath and therefore not very even.
It was during the 17th and 18th centuries that marmorino was most widely spread, especially in Veneto. The layer of lime and marble powder became thicker, on average four millimetres, which was then burnished with large irons to get a perfectly level surface. Usually they were applied on another layer of lime or terracotta granules, which were ideal in the damper zones. This application, very common in Veneto, also gave the name to Venetian marmorino, which means this combination of different layers of plaster.
As with natural stone, artificial stone – marmorino, was treated to increase its brilliance and resistance to the weather and in ‘L’Architettura’ by Leon Battista Alberti, we discover another wax finish or encausting, and a soap finish. The former is in fact a mixture of wax and mastic with a drop of oil, which was applied onto the dry plaster and then forced into the surface with the use of hot braziers; when cold the surface was then burnished until it was glossy. The second finish was much simpler and involved smoothing the last layer by soaking it with white soap dissolved in warm water. Two completely opposite effects were obtained, the first created chromatic saturation, suitable for small areas with very intense colouring, while the latter was more suitable for large areas giving a whitewashed finish. It must be remembered that ‘encausting’ should not be confused with the antique encaustic technique, which involved painting the plaster using colours mixed with wax.
In the 19th century, great changes took place due to increased labour costs meaning that the laborious lime applications became increasingly rare, while the so-called marmorino finishes increased, formed of chalk and glue, but which were false to all effects and, therefore, more rightly called stucco. Polished stucco, or Venetian stucco, involves mixing the colours and limewash with the stucco and then treating the surface with a hot iron when it is still fresh and then polishing it with wax paste. The effect is similar to the encaustic finish, but the materials are extremely different. It is curious to note the use of the Italian term, polished stucco in various European languages, which was brought about by the economic situation which forced these Italian skilled workers to take their craft abroad.
It is much easier to work stucco than lime, but the materials that are used are much less resistant, because chalk dissolves in water and glue is organic and therefore subject to biological attack. Even if the surface finish is treated to make it waterproof, as it absorbs moisture from the wall beneath, the surface decomposes. However the real difference is the appearance: lime, no matter how much it is polished with organic substances like wax or glue, always lets its crystalline matter show through, and glue and chalk finishes let the organic and gelatinous aspect transpire, even when they are polished with synthetic resins. In creating marmorino, especially with the traditional method, it is obvious that the better the binder mixes with the putty, without it cracking, the more compact and stable the plaster will be.
Therefore with marmorino and Venetian stucco, it is very important to select the right granulometry for the aggregate and the right tool: the iron, that special tool which is today called the metal plastering trowel.
In fact, it is the metal plastering trowel that lets the surface talk, which impresses the so-called surface values on the wall, which is that morphology that distinguishes work that is carefully and expertly done by hand.
These values are all those signs we can see on the surface and which are created by the movement of the expert hand using the most appropriate tools.
A plastering trowel for marmorino and Venetian stucco must be strong to give the right pressure, but must also have excellent fairing so that no marks or grooves are left to show the different passes. The plastering trowel therefore must be very flexible, with hardwearing fairing and a comfortable grip for the hand for even the most strenuous work.

Vanni Tiozzo

 

…FROM THE HISTORY OF MARMORINO
TO A LONG STORY OF MANUFACTURING EXPERIENCE…

For 150 years, Pavan, leader in made in Italy, has been serving professionals in the building and decorating trades and in fine arts, with a range of more than 1,800 professional tools: trowels, plastering trowels, spatulas, scrapers, brushes, knives, pointed trowels and tools for fine arts applications.
Constant attention paid to professional needs to make top quality tools that are distinguished by being hardwearing, comfortable and precise.
The special tools for marmorino, Venetian stucco and slaked lime putty are the highlight of the Pavan range. In fact, the firm has now created an exclusive case that contains all the indispensable tools for these splendid, historic decorations. The case contains the special tools that are the result of extensive experimentation, the spatula and the stainless steel plastering trowel for smoothing and polishing.
These tools are unique, the blades have curved angles, with milled and faired blade edges, with varying levels of flexibility. They are mirror polished for better application and easier cleaning. The handles are the result of very extensive research into the ergonomics of the hand, and the patented anatomic non-slip rubber handle guarantees a very secure and comfortable grip.
Ancora tools can be found in the best ironmongers, paint shops and building equipment and materials retailers, and are all guaranteed against any sort of production fault.
Pavan has always been a safe “anchor” for professionals in the trade.

PAVAN ERNESTO & FIGLI S.P.A.
Via XI Febbraio, 8 – 31030 Arcade (Tv)
Tel. 0422-874180 – Fax 0422-874108
info@pavanspa.ithttp://www.pavanspa.it/