The Roman stone wall of Seggau Castle in Styria, built in 1831, is permanently exposed to extreme weather conditions and requires regular conservation and maintenance measures. In June 2016, the Conservation and Restoration Department of the Austrian Federal Monuments Office (BDA) carried out trial and sample work for a conservation campaign and provided damaged Roman stones with conservation treatment. In addition, an overall concept is being developed, which includes both […]
The Roman stone wall of Seggau Castle in Styria, built in 1831, is permanently exposed to extreme weather conditions and requires regular conservation and maintenance measures. In June 2016, the Conservation and Restoration Department of the Austrian Federal Monuments Office (BDA) carried out trial and sample work for a conservation campaign and provided damaged Roman stones with conservation treatment. In addition, an overall concept is being developed that includes both sustainable conservation and proposals for measures to ensure better protection from the weather.
The Roman stones at Seggau Castle originate from the burial grounds of a former Roman town at the foot of the Schlossberg. The different types of marble were sourced from Lower Styria, Western Styria and Carinthia, but various signs of weathering could already be detected at the place of origin, depending on how long they had been in place. These had to be prevented by conservation measures. In the first century, the stones were used to quarry stone for the construction of a residential tower and chiseled into sculptural protruding forms.
The spolia were used once again when they became visible again after the demolition of the Old Tower and were built into an arcade wall as an impressive lapidarium. In addition, a sharp-edged geometric structure created by plaster framing created the effect of a picture gallery. The Roman stones were thus protected from the weather for almost 150 years under lime whitewash.
The process of decay of the Roman stones began again in the middle of the 20th century when the whitewash was scraped off during renovation work and microorganisms and algae penetrated the open spaces. The effect of water and frost caused them to grow even larger.
The BDA notes that the number of damaged stones has more than tripled since it began permanent monitoring in 1993. However, ultrasound measurements have shown that there is no further deterioration in the depths of the marble.
The aim of the restoration campaign is to maintain the existing appearance. During the trial and sample work, mechanical fine tools were used for cleaning on the one hand and laser cleaning on the other. The lime mortar technique was used to create small water-repellent embankments with small amounts of hydraulic additives. By backfilling with nanolime, it was possible to stabilize the crystal layers of the marble and at the same time fill the open spaces. During the course of the work, organic conservation materials were always avoided.
In order to ensure concentrated monitoring in the future, it is important to determine and document reference objects. High-resolution laser scanning technology will support the monitoring. The aim is to create a balance through targeted conservation measures and protective devices, which will be preserved through consistent monitoring in combination with care and maintenance.
You can find out more about stone conservation in Restauro 07/2016, which will be available for you in the store from October 10.
Additional information on the conservation campaign at Schloss Seggau can be found here.
