Ytbearbetning av ersättningssten för kulturhistoriska byggnader

Sammanfattning: The study investigates questions and considerations emerging when stone in historic buildings needs to be replaced. The focus is on the surface treatment of stone in sandstone façades in pre-industrial buildings. That means buildings constructed by traditional methods and craftsmanship without the use of modern technology. The research issue originates from the extensive stonework that is planned for the façades of the Stockholm Palace. The project includes the replacement of large quantities of damaged stone to newly cut stone. This raises the questions about the use of modern and rational methods for surface treatment on the replacement stone. The purpose of the study is to investigate the demands on the stone in large scale restoration projects and to find out what methods for finishing are available. In order to make observations from a recent project involving vast amounts of newly cut sandstone the reconstruction of the Dresden Frauenkirche is investigated. By conducting interviews with representatives from the current project at the Stockholm Palace and with persons involved in the planning and execution of the reconstruction of the Dresden Frauenkirche the considerations that emerge from a large scale project containing sandstone façades is exemplified. Literature on traditional methods for stone finishing is studied and the various stone finishes on the Stockholm Palace and on the Dresden Fraunekirche is investigated. Methods and technology of the modern stone industry is examined by visiting two large German stone producers, in addition a small Swedish workshop is also studied. The findings of the study indicates that important qualities of the traditional carved stone might be lost if modern machine finishing is used. Modern technology can however facilitate the shaping out of the stone. If such rational production methods is chosen it requires that the detailing of the stonework must be taken into account and the handwriting of the individual craftsman has to be allowed to appear in the finished result. The conclusion of the study points to that the best result for surface treatment of sandstone on historic buildings is achieved through traditional methods preformed by skilled craftsmen.