RESTORATION OF THE STUCCOES

OF THE BASÍLICA DE LOS DESEMPARADOS DE

VALENCIA

The art of stucco is one of the most remarkable,

and possibly the most sophisticated example of
the use of lime and gypsum. Likewise, fresco
painting is a highly refined form of artistic
expression also using lime. The technique of
polished stucco is technically very complex,
since the surface tends to harden rapidly. As a
consequence, the applicator must be highly
experienced, since the work must be performed
at a certain pace.

The PINTURAMA PROFESSIONAL magazine Nº17, published in 2007,

reported the beginning of the works for the restoration of the stuccoes in the
Real Basilica de los Desemparados in Valencia. This task required great
attention to detail, taking into account that traditional artistic processes had
to be used to recuperate the stuccoes. Consequently, ancient, almost lost
techniques and concepts had to be rediscovered to achieve this restoration.

We must consider that a large part of the stuccoes of the Basilica were
covered with paint, which had penetrated into the pores of the stucco,
especially where the last layers of stucco had been eliminated by grinding
and sanding in order to obtain a better keying surface (1*)
Views of the interior of the Basilica.
In the upper left photo, the dome is
reflected in the stucco finish, thanks
to the natural shine which can only
be obtained using traditional
application techniques, such as
polished stucco.

This article demonstrates the

meticulousness and complexity of
these types of works, which can only
be achieved by professionals
specialised in the restoration and
repair of works which form part of
the historic and artistic heritage of
our country.
INITIAL STATE OF THE STUCCOES

(1*) for the paint. In these cases, the porosity had

increased, causing severe internal damages.

The works were carried out by the ANDRES

GARBINO IDEAS DECORATIVAS, S.L. company,
considered to be highly professional stucco
specialists in Spain. The firm was selected among
a large number of companies, in view of its
professionalism and experience in the field of
restoration of buildings which form part of Spain’s
Artistic and Historic heritage.

Thanks to an experience of 14 years as plasterers

and to the meticulous study of research and
technological essays on the consolidation and
restoration of stucco plaster by the Italian restorer
Gino Piva in “L'Arte del
Restauro” and the
Swedish restorer and
scientist Sten Peterson in
“Lime water consolidation”,
the company ANDRES
GARBINO IDEAS
DECORATIVAS, S.L. was
able to establish a specific
methodology and their
project was accepted. The
company correspondingly
conceived a protocol of
action, specifying the
processes for the
conservation and
restoration works of the
stuccoes of the Basilica de
la Virgen de los
Desemparados, using the
“Restitutive Restoration”
method, which consists in
restoring the stuccoes to
their original splendour.
The attempts to clean the stuccoes with caustic products or similar
substances are ineffective and harmful to the stucco, given that
incompatible substances are left in the internal structure. In these
cases, the best solution is to replace them with new stucco using
the same techniques and the same materials as in the original
works, without causing much contrast between the old the new
stucco.
Referring specifically to the stuccoes, in some areas, these had
been painted while in others, they had been maintained but were
badly deteriorated.
In both cases, the processes were completely different and WHAT IS STUCCO ?
included not only the application of the finish, but also prior steps
of the process, such as cleaning, consolidation, reparation of
Stucco is a paste of gypsum, gypsum-lime or lime, used in
cracks and fissures and restitution of missing parts.
combination with other materials or unmixed, to plaster walls
Therefore, let us look at the work in its full dimension. The project without the need to paint, so as to obtain a marmoreal finish.
can be considered as a reference in the field of polished stuccoes These materials have numerous properties; smoothness of touch,
in Spain and a series of concepts must first be explained hardness, antibacterial, germicide, durability, lightness, resistance to
deformations, heat-regulating, absence of toxic products, beauty,
natural colouring, etc.
 WHAT IS POLISHED STUCCO?

Polished stucco is a mixture of gypsum and slaked

high-calcium lime to which alabaster dust and a wax-
based emulsion is added to increase its brightness,
providing a translucent effect after it has dried.

The art of stucco is one of the most remarkable, and

possibly the most sophisticated examples of the use of
lime and gypsum. Likewise, fresco painting is a highly
refined form of artistic expression also using lime.

The technique of polished stucco is technically very

complex, since the surface tends to harden rapidly. As
a consequence, the applicator must be highly
experienced, since the work must be performed at a
certain pace.

STATE OF CONSERVATION OF THE SURFACES

The surfaces presented the following characteristics:

-General superficial dirt produced by smoke and

contamination.

-Structural cracks.

-Cracks due to the detachment from the wall.

-Debonding with loss of fragments distributed over the

whole surface.

-Formation of pockets due to the detachment of the

different stucco layers.

-Radial cracks due to the contraction of the wall surface.

-Missing fragments in numerous ornamentations.

-Missing fragments caused by the installation of

ornamental objects and electrical equipment.

-Missing fragments due to vandalism.

-Pieces of non-stucco materials from previous works.

-Panels painted with matt white emulsion paint.

-Half-round mouldings painted with white emulsion

paint hiding the stucco.

-The dentil moulding of the upper cornice, the

tympanum and the cornice of the balconies, as well as
the archivolts of the entrances were gilded with false
gold on the stucco.

-The consoles of the upper frieze were painted in white

and the golden floral ribbing in false gold.

-Dampness.

-Fungi.

-Salts.
 WORK PROCESS ON THE SURFACES

Paint stripping

Several panels had been painted with emulsion paint. These were
stripped mechanically with extreme care to avoid damaging the stucco.
A number of these panels were recovered previously to be
subsequently restored. However, on other panels, the paint had
penetrated into the pores of the gypsum, especially where the last
layers of stucco had been eliminated by grinding and sanding in order
to obtain a better keying surface for the paint. In these cases, the
porosity had increased, causing severe internal damages, and as a
result could not be recovered. As we will see later, these were replaced
by polished stucco using the same technique and material as the
originals, as mentioned earlier.

Cleaning

During the works in 2003, a first dry cleaning process was carried out which
consisted in vacuuming the accumulated deposits and cleaning with erasers, ox
gall and wishab sponges.
The present cleaning process has been carried out using the procedure detailed
below:

1. Cleaning of the surface: TRISODIUM PHOSPHATE dissolved in deionised

water, applied with a sprayer, was used as a cleaner and degreaser.

2. Antiseptic treatment: the micro-organisms on the old stuccoes were treated

using an ETHYL ALCOHOL and PENTACHLOROPHENOL solution applied with
a sprayer.

3. In the areas where the deionised water solution did not have enough
dissolving power, an Ammonium Carbonate, Ammonium Bicarbonate and AB 57
solution was applied with a sprayer on 11 g. Japanese paper, over which a small
4. The areas stained in amber colour were
rubber roller or a brush was applied so that the dirt could adhere to the paper.
treated with an ethylene diamine tetraacetic
Several operations were necessary for the total elimination of the dirt, and the
surface had to be left to dry out totally between each application to avoid acid solution applied with a sprayer on
saturating the stucco with moisture. Japanese paper.
 History of the Real Basílica de los
Desamparados of Valencia
The Real Basílica de la Virgen de los Desamparados of Valencia, is considered the most
important late Renaissance building in Valencia.

The origins of this Basilica go back to a Guild named " DE LOS SANTOS MARTIRES y
DESAMPARADOS", which among other charity works, was in charge of burying the dead, the
executed criminals, the shipwrecked who were found ashore and the unknown who died in the city
and its vicinity. To this end, an image was ordered to be placed over the coffins of all the abandoned
and helpless people and also the members of the guild.

An icon was thereby created, which with the passing of time, was exposed on an altarpiece located
in an open chapel between the buttresses of the apse of the Cathedral. Owing to the increasing
interest and devotion shown by the Valencians for this image and the inadequacy of the chapel, a
new one was built. Thus, on the 15th of May 1667, during the reign of Charles III, the project
designed by Diego Ponce de Urrana, whose construction had begun in 1652, was finally enthroned
in the current Capilla Real

especially in this work, in the

shading of the natural shine of
the lime crystallization, where
an advanced stage of decay is
visible. The soluble sulphates
are solubilised in the stucco it-
self and the S04- ions link with
Ba++ ions to form insoluble BaS04:
S04- + Ba++_BaS04. Thus, the com-
position of the stucco is protected against salinization
formed by the reaction of the composition of one of the
gypsum elements (CaS04 2H20) with barium, which is
5. Elimination of the salts using the Barium transformed into an insoluble salt. Arbocel paper
method. The salts are responsible for the impregnated with this solution during a specific time was
deterioration of the intonaco, which can be seen, used for this purpose.
 WORK PROCESS ON THE SURFACES

Overall consolidation of the stucco

Several coats of limewater are applied. Good superficial hardening is obtained after a prolonged drying period and with the contact of the
carbonic anhydride in the air which reactivates the carbonatation, transforming the lime hydrate into lime carbonate (limestone).

REPAIR OF CRACKS

Radial cracks due to the contraction of the wall surface

Radial cracks without stucco detachment were found in some areas, The cracks were opened with a very fine prodding tool to remove the
especially in the flat areas of the frieze of the cornice. The cracks accumulated soot which had blackened the cracks. These were then
were produced by the retraction of the plaster from the wall, possibly filled with “aged” lime with honey additive. Stucco was not used since
due to an excess of lime in the dosage of the mortar or because the the cracks were too fine for the density of this material. Likewise, lime
stucco was applied while the base was still humid. grout was not used because the cracks were too wide for its use.

Cracks in the Cornice

Since the cracks in the cornice could not be filed with hydraulic lime
mortar, these were consolidated by introducing fibreglass applied with
a Primal AC 33 syringe. Once the adhesive was completely dry, the
missing stucco parts were stuccoed and the plaster was reunified.
 Structural cracks

The movements of the fabric, possibly caused by nearby

excavations, had caused continuous vertical cracks
running between the cornice and the semicircular
arches.

These were repaired using a special

extremely fine and very fluid hydraulic
lime mortar, to allow the mortar to
flow inside the cracks and completely
fill the space.

The applied mortar has elastic

~.-- - - ,- ---~ -
properties and great mechanical
resistance.

Structural cracks before and after

Cracks caused by detachment from the wall

In some areas, the black gypsum

plaster, which forms the wall support
of the whole Basilica, had detached
from the fabric, and in some cases
the different layers of which it was
composed were detached from one
another.

To attach the wall surface to the

fabric, 3mm holes were drilled in
strategic locations.

These areas were then washed by injecting water carefully to dissolve the soluble
salts and were left to dry. Methyl alcohol was then injected and also left to dry.
Following this, the glue was prepared with emulsifiable polyvinyl acetate and
calcium caseinate, prepared with one part of lime, two parts of casein and 20
parts of water. Pressure was applied to the area with a board until the following
day. Finally, the superficial part of the crack was filled with stucco.
 WORK PROCESS ON THE WALLS

Damp

The areas where the

wall surface and the
stucco had been
completely damaged
by humidity were
eliminated to uncover
the fabric and the
whole process was
redone.

NEW STUCCOES

Restoration in areas with detachment between the different layers of the wall surface and detachment
from the fabric, which owing to the extent of the deterioration, could not be consolidated.

The stuccoes of the arches of the Entrances and of the

Capilla de los Pies were covered with paint.

As we explained at the beginning of this article, this

type of paint penetrates into the porosity of the
stucco, especially where the last layers of stucco had
been eliminated by grinding and sanding in order to
obtain a better keying surface for the paint. In these
cases, the porosity had increased, causing severe
internal damages.

Attempts to clean the stuccoes with

caustic products or similar substances
are ineffective and harmful to the stucco,
given that incompatible substances
remain in the interior.

Following the paint stripping tests, large

areas were found where the stucco had
been eliminated and replaced with putty,
which had then been painted. For this
reason, since these stuccoes could not be
restored, it was decided to replace them
with new stucco using the same techniques
and materials as the original work. Great
care was taken to avoid contrast between
the new stuccoes and the existing ones.

Once the stripping was finished, a further problem appeared;

the layers of the wall surface had detached from one another
and in some areas had detached from the wall itself. For this
reason, it was decided to replace the base screed.

1. Elimination of the paint and stucco layer to uncover the wall 2. Elimination of the detached layers during the different
surface (support of the stucco). The stucco had to be eliminated application phases of the wall surface screed.
carefully by hand, leaving the support uncovered.
3. In the areas where the wall surface was detached from the fabric, the wall surface was completely eliminated,
leaving the fabric uncovered.

4. Positioning of fibreglass rods to reinforce the new screed.

5. Gypsum screed in said areas

6. Installation of fibreglass mesh on structural cracks

7. New plastering of the wall surface using a gypsum and calcium carbonate paste.

8. Reconstruction of the stucco using the same technique and materials as the original.
The stuccoes of the Basilica are known as “Estucos lúcidos” (Polished stuccoes). Their composition is described below:
-Fat lime.
-Marble dust.
-Gypsum
- Soapy solution
An albumen and boiled linseed oil solution is added to the compound to improve the workability and to retard the setting.
The lime is dyed with zinc white.
Restoration in areas with detachment between the different layers of the wall surface and detachment from
the fabric, which due to the extent of the deterioration, could not be consolidated.

Restoration of the Consoles

All of these ornamental elements were painted with

emulsion paint to imitate the stucco.

Given the high percentage of missing material from the

original stucco when the layers of paint were eliminated
from the consoles, it was decided to remove the stucco
and leave the base screed uncovered.

The consoles were then stuccoed again using the same stucco as the original one.
However, due to the shape of the console, it was impossible to use the conventional
technique and therefore, the stucco was applied with a technique known as “Painted
stucco”.

, With this technique, stucco of a very liquid consistency is applied in successive

layers (10 at least) and polished while still humid using a sponge or a dry paintbrush
between each application.

I
The last layer is polished with stone to obtain the same effect as on flat surfaces.
RESTORATION OF PAINTED MOULDINGS

Painted stucco technique

Lintels and convex mouldings

GOLD LEAF RESTORATION

GOLD LEAF RESTORATION