Anomalies in Wall Renders: Overview of the Main Causes of Degradation

Abstract

The assessment of historical buildings is usually focused on: 1) structural features related to brick or stone walls, wooden floors and other structural elements, or 2) highly valued decorative features, such as frescoes, stuccos, and facade details. During the last quarter of the 20th century, some “secondary” elements also started to receive their share of attention from researchers and practitioners. Wall renders are one of the most important of such elements because of their role as a sacrificial protective layer and the numerous problems that were encountered in the past as a result of incompatibility issues in rehabilitation works. This article discusses the main causes of the deterioration of wall renders, with emphasis on lime-based renders; these renders thoroughly reviewed and their relative weight in the overall degradation is addressed.

Keywords:

• mortar
• wall renders
• deterioration
• water
• climate
• biodeterioration
• human influence

ACKNOWLEDGMENTS

The authors wish to acknowledge the support of the ICIST research centre, at Instituto Superior Técnico. They also gratefully acknowledge the support of FCT (Foundation for Science and Technology).