Methodologies for characterisation and repair of mortars of ancient buildings

There is a clear need to de velop and systematise a methodology to approach interventions on ancient renders. In fact inadequate interventions, with systematic resource to modern solutions, originated in Portugal a situation characterised by the disappearing of original lime renderings and finishings and caused several anomalies due to functional incompatibility between pre-existing elements and new materials. The research project Oldrenders, accomplished by researchers from LNEC in collaboration with the construction enterprise STAP - Reparacao, Consolidacao e Modificacao de Estruturas, SA., and partially financed by Agencia de Inovacao , has as main objectives the definition of such a methodology and the preparation of criteria to support the selection of substitutive compatible mortars. This paper synthesises the aims and conclusions of the Project. 1. OBJECTIVES OF THE RESEARCH Interventions on ancient buildings included for too long the systematic remotion of the original renders, plasters and finishings and its substitution by render s and plasters based on Portland cement, painted with products based, first in oil paints and then in acrylic and vinylic resins. In the meantime, the theory of conservation has more and more pointed out the historic and aesthetic importance of preservati on of material evidences and their fundamental part in the definition of formal and material authenticity of historic artifacts.