Mural painting and fresco painting are not synonyms. What characterizes mural fresco paintings is that the colours are applied on a recently applied lime coating, before it dries. The time when to carry out this work is limited and conditioned by the setting time of… the render. A good render is very important for the execution and conservation of the mural painting. 

From the inside to the outside, the layers of mortar are the following:

1−Trullisatio, jaharrado finishing. Filling of the wall and screeding the surface to be rendered (maestreado). Lime with coarse aggregate. 

2- Arenato, rough render coat. Levelling the wall. Lime with coarse aggregate and medium-grain aggregate. 

3−Arriccio, render. Intermediate layer. Lime with medium-grain aggregate and fine aggregate.

4−Intonaco, plastering. Lime and fine marble powder finish. 

The mortar is spread out and compacted with the wooden trowel or float, in various layers (between three and six) to avoid contraction and cracking. Never must one add cement, since it contains salts which can arise and appear on the surface and which can destroy the painting of the top layer. The last layers must be applied on the same day, only the part which – according to plan – is supposed to be painted that precise day.

The range of colours mainly consists of iron oxides, from a yellowish ochre colour, sienna tones and browns, to reddish soil colour or sand-green colour. They also use black vine colour or iron oxide, cobalt blue and chromium green. White is the colour from lime itself. 

Mural fresco painting isn’t just an element which adds value by decorating a building, but an aesthetic component capable of integrating itself in quality architecture, enhancing its symbolic and spatial values. 

Bearing in mind the nature of the means to be used (plastering with lime mortars, painting throughout various days, etc.) it is advisable that the decoration of the fresco mural painting is included within the actual execution of the works, whether if it’s a refurbishment project or a project of new construction or rehabilitation. 

Apart from that, a fresco mural painting is an element to be taken well into consideration when there is a restoration intervention taking place of a building with historic, cultural or ethnographic value because of:

Its natural aesthetic integration,

Its capacity to include documentary information,

Its possible contribution to the correct reading of the building, in aspects as different as the historic and the composition-related ones,

Its possibility to allow an easy differentiation regarding original elements, 

The usage of materials which are 100% traditional (with no organic additives), totally compatible with old walls, which will preserve their original properties (breathability, flexibility, permanence, etc.),

The existence of great precedents of contemporary mural frescos in historic buildings: Monastery of La Rábida (D. Vázquez Díaz), the Opera House in Paris (M. Chagal), the Church of Leganés (M. Alcorlo), etc.,

It being a completely reversible intervention. 

Therefore, a fresco mural painting can be a very interesting option because of its great durability and high cultural and social prestige. Apart from that, its flexibility in terms of dimensions, elaboration, etc, enables a reasonable economic cost, completely manageable within the budget of architectural projects.