Marmorino is a form of lime plaster and calcium carbonate. It is the mixture that plays a major role in decorations in most great Italian buildings.
This technique was further developed and used widely by the Romans to create an actual discipline, Pompeii and Herculaneum are examples of the most creative aspects of this school, but it also can be seen at the Tombs of Via Latina near Rome. It would be over a thousand years before the stucco regained its pre-eminence, in the early sixteenth century. Raphael’s pupils, on rediscovering figures amongst the Roman ruins, brought to light the designs the decorations of Nero’s Domus Aurea. These beautiful grotesques were so called as they were found in these dark, cave-like rooms. From this initial thrust the unstoppable elegance of Renaissance wall decor would soon be widely appreciated throughout Europe.
With the explosion of Baroque in the seventeenth century, the hard plaster coverings occupied multiple architectural roles: for the walls, plinths, friezes, ceilings and cornices, capitals, mouldings and suspended high relief work, seemingly impossible to sculpt.
The decorative stucco ornamentation will gradually undergo developments in a constant search to create unique environments, never realised previously. This would all come together in the elegant “Eighteenth-Century Venice”.
The last significant example of marmorino plaster in architecture can be found in the works of the great architect Carlo Scarpa over the 1950s and 60s.
“Stucco Forte” is a type of marmorino, yet the decorations have as structure of mixes that can be defined as pozzolanic and semi-hydraulic, these types of plasters are tough and very durable, indeed they are still intact after thousands of years on the external walls of Roman aqueducts. These tricky-to-create lime mixtures are incredibly still in use today in Venice. In the decorations of the sixteenth century used thick applications and so required extra cocciopesto (browncoat made from terracotta tile fragments) or pumice to give strong gripping support to the marmorino layer in the construction phase. Gypsum alabaster was only used internally for ceilings for a quick-drying solution.
The finishing and polishing are strictly marmorino (seasoned slaked lime and calcium carbonate).
Venetian marmorino in essence is a mix between slaked lime and powdered marble. Create any environment; a living room, a bathroom, a marmorino facade, signifies a complete plastering of the surface area with this mixture, applied with the Venetian method. The build-up of many coats (at least eight, but many more for specific functions), create a transparency, the signature by which true marmorino Veneziano can be identified. The Italian term intonaco for plaster (verb: intonacare) derives from a monk’s cassock, the cowl (la tonaca) and then the concept of dressing soberly inside, a basic protect from inclement weather. The plasterer is the person who knows how to handle lime well and respects the correct timings of its application. Moreover, someone with the right tools and techniques for mixing and applying Venetian plaster.
The Venetian ‘stucco’ plaster comes from the Venetian ‘strucar’ meaning to press. This mixture is for constructed decoration in bas-relief (ornate stucco) as leaves, flowers and other decorative motifs. To model or form the stucco specialist tools are used, called simply ‘ferri’ (irons) or ornate stucco irons. The technique of pressing the lime mixes has been synthesised in this way, with this terminology born out of the on site working situation. Pressing is a fundamental process that changes the result of the work as well as its duration, but must be made at the appropriate time in the final stages of processing.
The advantages of marmorino
This plaster exhibits a great range of practical qualities: firstly its biocompatibility with the environment, the calcium carbonate has a nearly pure reversibility equal to 100%. Thus in the event of disposal it is an identifiable material. It is not another mysterious industrial compound (not recyclable, non-restorable) – it is calcium carbonate. Its long life and durability is a guarantee to professionals. It is restorable with excellent results even after centuries. Its breathability and then its rapid drying allows the masonry to remain dry and enables a building excellent thermal protection, as well as to keep any beams far from standing water, not only protecting the wood but the whole structure. It’s a material with an attractive finish and can be coloured with natural pigments. It is highly plastic so details can be created easily. Marmorino Veneziano surface actually improves with age (unlike cement mortars that are ruining our town).
Some further recommendations
To the most passionate apprentices on this topic there is the book written by Master Plasterer Mario Fogliata and Maria L. Sartor: L’Arte dello Stucco (the art of stucco — first published by Edilstampa in 1995, republished by Antilia in 2004). This book too has become rare. Some other practical tips are to look for the right materials, and this will be one of the topics covered in a future article. As for the marble powder, we recommend using Mineraria Sacilese (Caneva-Sacile), a quarry of almost pure calcium carbonate, perfect for marmorino finishing. To know where to find the most suitable lime in your area, you can ask Forum Italiano Calce (Italian Lime Forum), an association that deals with all aspects of lime in a commitment way.