Monitoring façade soiling as a maintenance strategy for the sensitive built heritage

ABSTRACT

The color patterns generally found on the façades of architecturally sensitive buildings have an adverse impact on their aesthetics, to the detriment of their identity and potential economic value. A quantitative and qualitative study was conducted of the perception of aesthetic decay in the limestone on a heritage building. The study assessed building aesthetics between two façade cleaning operations, conducted in 1984–1986 and 2006–2008. Based on the calculation of the final or total soiling index, by means of in situ lightness measurement and three architectural design variables, the color distribution of the façades was quantified in 2006 and a model was developed to monitor façade soiling over time. The proposed model, a tool for planning preventive façade maintenance on architecturally sensitive buildings, advocates for sustainable cleaning operations. Its premise that periodic cleaning should only be conducted in areas where the limestone is affected by aesthetic decay redounds to minimised intervention and lower building management costs.

KEYWORDS:

• aesthetic decay
• cultural heritage maintenance
• façade design
• soiling perception
• stone cleaning

Acknowledgments

The authors gratefully acknowledge the support provided by José María La Calle, former Deputy General Director of Architecture of Madrid’s Regional Department of the Environment, Housing and Land Management, and José María Cabrera, chairman of the company CPA, S.L. Special thanks are due to CPA, S.L. employees Santiago García, Joaquín Grande, José María Pulpón, Bárbara Pérez, Fernando Frade, Sergio Calmaestra, and Selene Castro. The authors greatly appreciate the comments suggested by reviewers, as their considerations have improved significantly the research addressed.

Additional information

Funding

This study was funded by the Regional Government of Madrid, Spain and the European Social Found [Geomaterials (S2009/MAT_1629) and Geomaterials 2 (S2013/MIT_2914) Programmes] and by the Complutense University of Madrid research group “Petrology applied to heritage conservation” [ref. 921359].