Plaster of cocciopesto

When it has to do with walls in rather humid places, to work around this problem it may be useful to apply to the walls a plaster in cocciopesto.

This type of plaster is made of a base of lime to which is added bricks powder, which gives to the mixture very good hydraulic properties, which enable it to resist to moisture.

Because of its characteristics, the cocciopesto was widely used by the Romans for the construction of aqueducts, storage tanks, walls and streets because it is particularly suitable for humid walls.

Why choose a cocciopesto plaster?

The main cause that leads us to use this plaster with the base in cocciopesto, is the rising damp, which can be caused by a number of factors, such as the absence of foundations, the lack of adequate waterproofing to the base of the building, the fact that the construction can be partially buried etc. ..

To solve this problem, we may also intervene in other ways, for example by digging trenches along the perimeter of the building so as to allow ventilation of the underground part of the walls. We can also use a breathable lime-based plaster with a macroporous structure in order to provide a large surface area of evaporation, although this solution does not solve the problem but it softens it.

The cocciopesto can be used both indoors and outdoors. Its properties make it a coating that can give greater breathability to the damp walls. But this can also be used as a waterproof plaster, in environments such as bathrooms and kitchens.

To make it waterproof we must spot-facing it with the aid of a trowel so as to close all the pores and obtain a very similar effect to a polishing, which makes it therefore impermeable to vapor which is usually generated in these environments.
This type of plaster is easy to manufacture and is fairly quick to lay on site, it also has a good durability because of its excellent transpiring and hygroscopic abilities and it gives an attractive aesthetic effect on the wall on which it is layed.

The colors of this type of plaster with a cocciopesto base, on the market are essentially two: pink or yellow, depending on the type of brick crushed and mixed into the mixture.
It is a pre-colored plaster and therefore does not require painting later.

How to create a cocciopesto plaster?

The elements for the realization of this type of natural coating, which as we have seen recalls the ancient building techniques are: lime natural sand plaster and bricks or tiles that then at a later time will need to be finely ground so as to create powder.

The lime natural sand plaster, which is perhaps is the element much harder to find, is obtained by turning off the lime with the help of water. This extinguished quicklime, is left to rest for a certain period of time inside tanks; this will result in slaked lime.

The bricks powder is obtained by crushing clay and full bricks, which are scraps of cooking, ie those bricks that have not been cooked at appropriate temperatures and are therefore not suitable for construction. After the grinding this powder is sifted in order to eliminate the larger remains that can not be used.

Laying the cocciopesto plaster

The methods of laying are similar to those of a normal plaster, in fact after wetting with plenty of water the wall that you want to coat, you lay a first layer of plaster with a thickness of about 1 cm. Then let it dry, until when trying to touch it won't show the fingertips.

Then you lay a second layer of cocciopesto plaster, again with the same thickness, which will be then standardized by leveling the entire surface.
The last layer of finish to be layed on the wall is achieved with what is commonly known as plaster. This is nothing more than a mixture, made again in cocciopesto, but with a much finer granulometry.

This plaster is applied on the wall a layer with a thickness of about 0.5 cm, which will be left to dry and then we lay a second one; later it will be stardardized as well with the aid of a sponge float.

Depending on the direction in which you will move the float, which may be vertical, horizontal or circular movements, the effect that you will obtain will be different, this because, depending on the different movements the aesthetic effects on plaster will be the most varied.

If you want to obtain a completely smooth finish you can work with a metal trowel. Obviously the choice of the different techniques depends only on the preferences and tastes of the customer.