Restoration of the main façade of the castle of Pallejà with the REVAT CAL system.

Descripción sistema

The castle of Pallejà is a castle-palace dating from the 16th and 17th centuries, whose architectural style is that of a building in transition from civil Gothic to Renaissance.

It was built by Ramon Martí de Torrelles in 1590 on top of an earlier tower or fortification, documented from 1179. Later, in the second half of the 18th century, it was converted into a hotel and, in the 19th century, during the Spanish War of Independence, it served as barracks for both armies.

It was acquired by Pallejà Town Council in 1992, and in 1995 work began on its consolidation and remodelling. The castle has now been restored as a cultural and social centre.

The entrance is wide, with two arches covering the vestibule and a staircase at the back. It is an almost square building with a ground floor and three storeys. The upper floor has sentry boxes dating from a later period. It is made of stone and wall, with a stucco surface that simulates the masonry. In the corners there are large blocks of carved stone. The doorway is a semicircular arch with voussoirs, and the noble coat of arms of the Torrelles family can be seen at the top.

Old photographs show that the castle had several buildings attached to it that were demolished in the 1960s:

Reason for the intervention

“The lower area of the wall is affected by capillary rising damp, which comes from the ground and rises up the wall as it “absorbs” it. This moisture affects the bond between the coating mortar and the substrate, causing it to detach.

“With regard to the upper area, the dampness is related to the lack of a drip edge in the cornice, which means that all the water collected in that area of the façade is concentrated just at the beginning of the following rendering. As can be seen in the photograph, all the dirt on the flat surface of the cornice runs down the façade when it rains, staining its surface, which consequently becomes blackened.

“Water seepage between the exterior render and the stone wall also affects the bond between the materials, causing gaps or spalling.

Challenges and constraints

“Characterise a cladding system that is as compatible as possible with the type of old material with which the façade is constructed.
“The system must be impermeable to rainwater and have a high water vapour permeability.
“Its colour and grain size must be such as to reproduce as closely as possible the appearance and texture of the original cladding.

Molins Solution

“Choose a mortar shade that best matches the original colour of the coating.
“Eliminate areas without cohesion or loose parts, until the substrate is firm and stable.
“Ensure the homogeneous behaviour of the fixing surface with PROPAM® DUR.
“Apply REVAT® CAL FONDO lime-based surface levelling mortar.
“Apply the lime-based coating mortar REVAT® CAL TRADITIONAL.
“Ensure that there are no points where leaks can occur.

Execution

“In order to choose the colour of the new façade cladding(REVAT® CAL TRADITIONAL), some fragments of the old plaster whose exposed face had different shades were taken to the Molins SAU laboratory in order to reproduce them in the new mortar. Once they were obtained, four samples of about 5 kg each were made and then taken to the construction site to decide on the most suitable one.
“2. At the same time, work began on the façade; first of all, it had to be ensured that the substrate was resistant, stable and free of dust, organic products, etc., so some tests were carried out to determine the necessary surface to be repointed.

“3. Once the plaster in poor condition had been removed, the PROPAM® DUR consolidant was applied to give firmness and stability to the surface of the substrate, and to homogenise its behaviour prior to the application of the new coating.

“The surface levelling was carried out with REVAT® CAL FONDO (GP-CSII-W0 according to UNE EN 998-1) reinforced with REVAT® fibreglass mesh. Formulated with aerial lime, selected aggregates and additives, this mortar is indicated as a bonding coat on mixed substrates, prior to the execution of the finishing coat. It has a high vapour permeability µ≤6. It was applied manually, applying a first layer of between 5-7 mm tightly against the substrate; then, when fresh, embedding the REVAT® 110 mesh in it, and finally a second layer <2cm with which it was possible to obtain the required planimetry for the application of the finishing layer.

” 5. Application of REVAT® TRADITIONAL LIME samples to choose the colour of the facade.

“6. Application of REVAT® CAL TRADITIONAL LIME (GP-CSI-W2 according to UNE EN 998-1) coating mortar on top of the previous regularisation layer. Formulated with an aerial lime base, selected aggregates and additives, it is suitable for restoration and rehabilitation works where mortars with traditional characteristics are required. It is impermeable to rainwater and has a high vapour permeability µ≤15. Since the original texture of the façade had to be reproduced, it was applied manually in a thickness of 1 to 1.5 cm.

“Before and after
The excellent final finish is in keeping with the initial aesthetics.

Technical note

LIME-BASED COATINGS
The Technical Building Code (CTE) is the regulatory framework currently in force in Spain, which makes the suitability of lime mortars for use in the building sector a very topical issue. Thanks to their properties, aerial lime mortars comply satisfactorily with the Basic Documents HS1: protection against humidity, HS3: indoor air quality and HR: protection against noise.

This is due to the fact that the use of lime as a binder gives the mortars a bioclimatic capacity, as it allows the wall to transpire due to its high permeability to water vapour, facilitating comfort and indoor air quality, while at the same time waterproofing against rainwater.

REVAT® LIME SYSTEM
The mortars of the REVAT® CAL system are:
” Impermeable to rainwater.
“Highly breathable and permeable to water vapour.
“Indispensable in renovation and dehumidification operations, in substrates with capillary rising problems.
“Highly resistant to attack by salts from the wall.
“Highly compatible mechanical and elastic characteristics with the traditional materials that make up the original construction.
“Very good workability and creaminess.
“Can be used indoors and outdoors.