On‐site performance assessment of rendering façades for predictive maintenance

The purpose of this paper is to present a methodology in order to improve inspections' diagnosis during façades' service life through in‐service criteria. On‐site performance assessment and deciding on the maintenance of renders can only be improved if quantitative parameters are pre‐established at the design stage and monitored under service conditions.

The methodology is based on a set of in‐service parameters inferred from visual observation and measurements and their methods of assessment (based on visual inspections, auxiliary techniques, in‐situ and laboratorial testing). These have been arrived at by inspecting the façade rendering on 44 buildings (cement‐based renders), of different ages and types of degradation.

This paper focuses on 23 proposed mechanical and physical‐chemical parameters that can complement the ones already established by standards or technical data, obtained in lab conditions, using standard specimens or small models. They are assessed by techniques that have been applied to renders or other façade elements such as concrete or timber structures. The reliability of this in‐service performance assessment is discussed together with its potential as an aid to deciding on predictive maintenance action after an inspection's diagnosis.

The originality of this approach stems from the fact that in‐service parameters derived from both laboratory and in‐situ measurements can improve understanding of the behaviour of façade rendering, which is an important step in planning and monitoring maintenance. Two aspects are emphasised: the behaviour of materials/systems is assessed in real conditions, and the subjectivity of in‐service diagnosis is reduced when more than one performance parameter is assessed.