A study on the effectiveness of biological growth resistant coatings on external building façade systems in the tropics

• Published in: Journal of Building Engineering 2020-09, Vol.31, p.101377, Article 101377
• Main Authors: Asmone, Ashan Senel, Chew, Michael Yit Lin
• Format: Article
• Language: English
• Subjects: Biological growth; Building façade; Digital image processing; Facilities management; Surface coating systems
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2020.101377

Traditional façade cleaning processes can be dangerous, labour-intensive, and impairs the ease of façade maintenance. Thus, in improving the maintainability of the façade systems, facility managers search for novel strategies to reduce the cleaning cycles. Façade systems in tropical cities are frequently and severely affected by biological attacks such as algae. However, there is a considerable dearth of knowledge on the effectiveness of novel façade coating systems; proposed to prevent biological growth in tropical buildings. As part of an on-going effort to create a material manual, the effectiveness of six commercially available façade coating products on three different substrates (granite, aluminium, rendering materials), of a building under Singapore's tropical conditions to inhibit biological growth is evaluated. On-site photogrammetric data were collected over six months to analyse using an updated novel digital image processing procedure to evaluate the development of biological growth on the façade. A lifecycle cost (LCC) analysis is carried out for each type of façade coating application. The analysis from site measurements showed that all products exhibited improved performance on keeping the surfaces cleaner than the untreated façade surfaces. As the level of improvement varied between different substrates, a façade cleaning index is defined for each coating system. A lifecycle cost analysis showed varying results on the improvement in the performance of the products applied. A general reduction in cleaning cycles favours the facility's operating costs for granite and aluminium substrates. For rendering materials, the high cost associated with the application appeared to make the LCC less attractive. •Biological growth over time observed on three building substrates in the tropics.•Biological growth inhibiting façade surface application effectiveness was observed.•Application of photogrammetry data analysis using digital image processing procedure.•Surface coating products have varying effects on the different substrates.•A substrate dependent facade cleaning index is defined for each coating system.