Deterioration of buildings and monuments, which are exposed to weathering and pollution, is becoming a serious life-cycle problem, causing economic and cultural damage.
One of the main causes of decay in porous materials is the growth of salt crystals within the pores, generating stresses which are sufficient to cause disintegration and hence causing a loss of the historical and artistic importance of the monument. Nevertheless, there are many examples known of treated monuments where no damage is observed, even 20 to 30 years after treatment.
This leads to the hypothesis that, since no building material is completely free of salts, it must be possible to define limits of salt content related to the type of salt and the material properties, below which a surface treatment can be safely applied. Up to now, this limit has never been defined. In diff`erent countries arbitrary defined values are applied ranging from 0.05 % to 5 %.
This project aims to investigate the salt compatibility of surface treatments, more specifically to:
- determine the types of salts which need a special precaution in taking adecision for treatments
- study the influence of the treatment on the salt distribution andredistribution in the wall
- evaluate the influence of the treatment characteristics on the damage
- correlate limit of salt content to the substrate properties.
The assessment of the salt compatibility of surface treatments will result from:
- the state of preservation in practice
- laboratory research on single materials, wallets and full scale models, forwhich the choice of the types of substrates and products will be based ontheir representativity in the major part of Europe.
The results obtained from the two research lines will be combined and presented in such a way they can be easily used by a non-specialist. The final goal is to provide information of the limits of salt content, related to material properties and treatment characteristics, below which a surface treatment is allowed. This information can help in the elaboration of a new European standard and will contribute to prevent deterioration of historic buildings caused by surface treatments.
This project will be executed by a consortium of 4 partners (P1,...P4) and an end-user (EU) who participates as a subcontractor of partner 2 (P2). Partner 1 (Pl) is the coordinator and partner 2 to 4 (P2,.. P4) are contractors. P1 to P4 represent research institutes, while EU is an administrative unit responsible for the care of all historic buildings in Paris.
Funding SchemeCSC - Cost-sharing contracts
2628 VK Delft