TRADIZIONAL PLASTER FINISHING TECNIQUES

“INTONACHINO”● The traditional recipe is composed of lime, sand

and natural pigments (mineral origin) resistant to the action of caustic lime.

● Starting from the nineteenth century iron oxides and metallic artificial salts were used; they resist better to whitening but often obtain colors that are too bold.

● The quantity of pigment should not exceed 10% of the quantity of lime

● A colored intonachino is spread on the dried second layer (arriccio). One to two coats are applied in order to reach a 2-4mm thickness. Once it begins to dry you can smooth it out with wood or with a trowel.

● This finish has the advantage of good resistance, provides naturally marbled surfaces and is very good on construction history.

● The coloring can be obtained even using only colored sands or brick dust.

SMOOTH LIME● It is made by spreading very thin layers,

gradually reducing the quantity and size until you have only lime.

● It is possible to color the plaster obtaining a more uniform surface

● For the last layer you use only lime, without sand, but the plaster is applied by brush and smoothed with a trowel. If the last layer is too dry, it is important to wet it a little before applying the lime.

● If you mix soapy water (Marseille Soap) to the final layer you can the result will be bright and shiny.

● On top of the finished plaster you can apply a coat of wax (1 part) and soap (2 parts) dissolved in warm water to increase the shine and protection.

“GRAFFITO” o “SGRAFFITO” PLASTER

It is a decorative plaster, used to create naturalistic or geometrical drawings, in two or more colors

Since the 14th century, it has often been used in external facades to mimic a stone wall

In Florence, Rome and other Italian cities, there are many examples of “sgraffito” facades, dating back to a period of time ranging from the 1400s to the early 1900s.

Techniques

1. You can spread the final layer on top of the second layer of plaster (“arriccio”) made of lime and sand

2.The last plaster layer is made with 1 part of lime and 2 parts fine sand with added color, usually black or brown obtained by using burnt clay or natural origin oxides, compatible with lime. In ancient times burnt straw or charcoal were used.

3.When this layer of plaster is almost dry you layer two or three coats of lime dissolved in water (1:10 ca) with a brush to obtain a white surface

4. On this surface you have to trace the drawing: - the simplest way is to imitate the stone. You

draw the lines with a thin rope soaked in paint powder by dabbing it against the wall;

- A more complex way is to reproduce the drawing on cardboard or glossy paper and perforate along the outline of the design; then you dab a bag containing colored powder on the perforated paper to transfer the drawing onto the wall.

5. You then engrave the outline of the drawings with suitable tools

6. Scratch the white surface layer in areas where you want to see the darker color. There are usually two layers of color, but sometimes it’s possible to find three colors

EXAMPLES OF SGRAFFITO IN FLORENCE