Jesuit College, Kutná Hora, Czech Republic

Reconstruction of the Jesuit College was one of the projects in the program ‘Replacement of buildings returned to owners during the Restitution’, sponsored by the Ministry of Culture of the Czech Republic since 2000. The Jesuit College complex was taken over by the administration of the Czech Museum of Fine Arts as a substitute for the loss of its premises in Nelahozeves Castle.
Before the complex could be converted for the purposes of the museum, archaeological, conservation and technical research had to be carried out and it began towards the end of 2004. Architectural historical research had already taken place in previous years.
The extensive restoration research was the responsibility of GEMA ART GROUP a.s. The aim of the experts was to identify the most suitable course of action during the building work so as to minimize any unsuitable interventions to the Baroque monument. The research under the leadership of GEMA ART GROUP a.s. took place from October 2004 until 2005. Additional restoration research was carried out during 2006.
GEMA ART GROUP a.s. was responsible for a survey of the rendering on both the exterior and interior walls and also the woodwork and the flooring within the Jesuit College. The exploratory probes uncovered a Baroque drainage duct, whose function was to be renewed.
Apart from the restoration research and submission of reports on it, and the drawing up of the technical and restoration schedule, GEMA ART GROUP a.s. also took part in the actual specialist work. This involved, for example, the extensive uncovering and overall surface cleaning of the original frescoes and stucco ornamentation within the premises of the refectory, salvation of the fragments of the Baroque grilles, restoration of the stone cladding of the doorways and the windows and restoration of the 17th century flooring.

Restoration of the stone water conduit in the north wing of the building:
This is a valuable fragment of the original drainage system. The stone duct made from Kutná Hora arkose stone is located on the first level above ground in the north wing of the College. Its function was to drain water away from the walls of the room.
The duct was covered by a black crust, the stone had degraded and in places had fallen apart. The duct was taken apart and rid of the crust and dirt both mechanically and using chemicals, namely ammonium hydrogen carbonate paste.
To follow, the stone was repeatedly spray-coated. Missing and damaged parts were reconstructed using a mineral based cement with iron oxide coloured pigments. To conclude the stone was treated with a siliceous acid ester based hydrophobic agent.

Survey and restoration of the façade of the Jesuit College building:
An extensive survey of both the main and the courtyard façade and well as the façades of the two cylindrical and one polygonal towers of the complex was carried out prior to the restoration work. The insertion of probes over large areas had already started in 2005 with the aim to establish the original colour of the façade. The probes uncovered partially preserved original plastering from the 1670s. The age of the samples taken was confirmed by laboratory tests. On the ground floor bossage fragments of the original Baroque white and grey paint were discovered under a later ochre layer. On the lesenes the original pale ochre paint was noted under the newer green layer. The capitals of the pilasters were also subjected to material composition analysis and dated to the beginning of the 20th century.
GEMA ART GROUP a. s. was in particular responsible for the renovation and repair of the rendering and stucco on the towers of the Jesuit College. The restoration work was based on the results of previous surveys. Weatherworn and crumbling layers of plaster were removed and replaced by rendering resembling the original. The viable parts were strengthened using potassium silicate. Stone elements on the façade of the towers were consolidated by an organo-silicate based agent. Outer layers of the capitals were treated with a hydrophobic substance.
Work on the façade of the towers also included restoration of the stucco surround of the clock face and the stucco decoration beneath the clock face.

Survey of the interior walls of the main building of the Jesuit College:
Spot testing of the colour schemes of the interior walls and stone and stucco elements had already been carried out in 2004. Two years later an additional restoration survey was undertaken in less accessible areas. During both of these surveys ochre-brown frescoes with graphic lettering and fragments depicting a house were discovered. This original wall painting was covered by several layers of later plastering. The experts came to the conclusion that the walls of the Jesuit College were originally decorated with figural motives and other wall paintings.

Restoration of the windows of the Jesuit College:
Restoration of the 107 windows of the Jesuit College took place from October 2006 till January 2007. The windows were single or double with two to six casements furnished with external metal fittings. The windows showed considerable mechanical damage, the wooden window frames were affected by rot and woodworm. In the majority of cases the damage was most extensive in the lower parts of the frames. The fittings were corroded or altogether missing. The glazier putty was loose and in places had fallen out.
Before the windows were dismantled, a thorough photo documentation and verbal description was prepared. In the restoration workshop the newer layers of varnish were removed using hot air guns and scrapers. The individual window frames were taken apart and where required partially or completely replaced by copies. Loose glazier putty was also replaced. Broken or missing glass panes were replaced by copies. Where the glass was merely scratched it was left in place. The wood was coated with a paint with added rot and woodworm preventative agents.
The metal fittings were re-attached, missing parts were replaced with copies. The surface of the fittings was treated with anti-corrosive coating.

Restoration of the stone casing of the doorways in the Jesuit College:
The restoration research, which took place from December 2004 until March 2005 also included the survey of the stone casing of the doorways within the premises of the former Jesuit College. Almost all the casings were made of local Kutná Hora arkose stone covered with layers of varnish. Decorations on the casings are minimal. The casing is formed by a single frame divided by a chamfer and edged by a fascia. The raised sill stone is extended by tasselled ears.
The most valuable type of casing, which differs from the others, is the later installed sandstone portal on the second level above ground. The portal has a rich sculptural ornamentation. In comparison with the other casings made from Kutná Hora arkose stone, which exhibited considerable lack of cohesion, the fine sandstone of the portal showed little signs of damage.
The surface of the Kutná Hora arkose stone casings was first mechanically cleansed. The cleaning process revealed extensive degradation of the stone and for this reason a repeated pre-consolidation by an organo-silicate based agent was carried out. Undisturbed original pointing was retained, the missing areas were in-filled using a more elastic lime mortar. Some moulded ornamentation of the casings was severely degraded or altogether missing and had to be reconstructed, with all the re-modelling carried out to resemble the original shape of the stone. Mineral based fillers with a weak solution of acrylic dispersion were used in the reconstruction process. To conclude, colour retouching using an iron oxide based preparation was carried out.

Restoration of the Baroque wrought iron grilles:
Restoration of the grilles took place in the second half of 2006. There were in all 11 window grilles in the refectory and on the second level above ground in the central wing of the Jesuit College. The grilles were found to be in a poor state with extensive corrosion. Unprofessional past repairs did not improve the matter. Apart from two instances in the refectory, all other grilles were original only in parts. Some of the grilles had in the past been partially cut out, probably for access. Amateur welding together of some of the parts was also visually incongruous. Fragments of metal flower heads, a typical decorative element of the Baroque style, were found on some pieces of the grilles.
All grilles, after detailed photo documentation, were taken apart and cleaned by sand blasting. Seriously corroded parts were replaced by copies. After removal of the old coating and treatment with an anticorrosive agent, the surface of the grilles was painted with black matt paint with the addition of graphite.

Removal of cement floors and restoration of the Baroque flooring and staircase within the premises of the Jesuit College:
During the comprehensive restoration and technical research carried out by GEMA ART GROUP a.s. from December 2004 till March 2005, a technical blueprint for removal of the cement floors was also drawn up. Cement floors with bitumen coating were found in the corridors of the former College. In the north wing, ceramic paving was laid down on a cement base. The flooring probably originated from the 1950s, when the premises were used as a military warehouse.
The results of the technical survey showed the vulnerability of the vaulting to loads in excess of 700 kg per m². As some vaults had signs of compromised static stability it was not possible to demolish the floors by pneumatic drilling technology. The cement slabs were first cut up into smaller pieces by diamond drills, with the depth of the cuts calibrated by the experts so as not to damage the vaulting underneath.
Remains of the original Baroque paving made from Kutná Hora arkose stone were noted in the corridors on the first level above ground within the south wing of the building and underneath the main building staircase. The paving exhibited signs of extensive damage. The stone was crumbling and the slabs were broken or cracked in many places. The surface was covered by dirt and dark crusting. The paving was photo documented and the position of individual slabs recorded in the layout before the dismantling took place.
After the crusting was removed the most damaged areas were locally pre-consolidated. The surface was then cleaned using pressurized water and then consolidated using an ester of a siliceous acid based agent. Missing parts were reconstructed using mineral fillers and colour harmonized using ferrous pigment. Where the stone was too degraded, copies were made from Božanov sandstone. Usable but partially broken slabs were glued together using epoxide resin. Re-pointing was done using a lime mixture mortar.
Identical restoration procedures were applied to the fine sandstone staircase of the main building, after its surface was rid of the artificial stone cement-based layer.

Restoration of the refectory of the former Jesuit College:
Restoration work on the premises of the College refectory took place during 2006. The refectory was built between 1667 and 1750 on the first floor of the Jesuit College. Subsequent building alterations took place in 1776, 1843 to 1846 and in 1858.
The work included the renovation of the original stuccoes and frescoes which had been over the years repeatedly covered by layers of lime paint. The depth of these layers reached 7 centimetres in places. The layers not only covered the frescoes but also the profiling and shape of the stuccoes, which were as a result entirely devalued. Frescoes framed by ornamental stuccoes were located both on the ceiling and side walls of the refectory and were found to be covered by up to twenty layers of lime paint and plastering. Some parts of the frescoes had turned black under the influence of alkaline lime remnants and oil-based paint.
Uncovering such large areas was a demanding task. Removal of the covering layers was carried out centimetre by centimetre using scalpels. So as not to damage the frescoes, careful ongoing in-depth and surface securing of all loose parts took place. Each portion of uncovered wall painting was approached individually and always after consultation with representatives of the Heritage Institute. The cracks were sealed using a mixture of lime, sand and water. Subsequently re-touching was carried out using aquarelle and tempera paints. The uncovered frescoes depicted the Legend of St Barbara and other religious themes. The overall hue of the frescoes’ surface was red-brown. The restorers also discovered the signatures of the artists: their names were Schmid and Kus.
The decorative stuccoes were also restored. During their examination remnants of blackened gilding were recorded.