A practical approach to in-situ evaluation of surface-treated structures

This paper describes the result of a field evaluation carried out to ascertain the effectiveness of hydrophobic and consolidating treatments applied to the surfaces of three historic buildings and monuments in the UK. The surface treatments were 7–18 years old at the time of testing. The field trials were carried out using a simple but practical suite of complementary and wholly non-destructive test methods. The methods, procedures and criteria used for assessing the performance of surface treatments used were developed from an EC sponsored laboratory and site test programme carried out on stones representing those used in the construction of monuments across Europe. This approach has been shown to provide useful, early warning information to owners of historical or modern structures, which will enable them to make an informed decision regarding when to treat a deteriorated surface or the need to re-treat an already treated but subsequently weathered surface. The results obtained suggest that the treatments applied on some of the tested structures have deteriorated to the extent that it is now time to consider re-treatment.