Mould and phototroph growth on masonry façades after repainting

Title: Mould and phototroph growth on masonry façades after repainting
Author(s): M. A. Shirakawa, V. M. John, C. C. Gaylarde, P. M. Gaylarde, W. Gambale
Paper category : journal
Serial title: Materials and Structures
Abreviated Serial title: Mater. Struct.
ISSN: 1359-5997
Publisher: RILEM Publications SARL
Volume: 37
Issue: 271
Issue date: 2004-08-01
Publication year: 2004
Pages: 472 - 479
Total Pages: 8
Nb references: 21
Language: English

Abstract: The appearance and durability of paint films are affected by microbial growth and fungi and phototrophs are considered to be especially important, degrading the films mechanically, by the production of metabolites, chiefly acids, and by enzymatic activity.
In this study, fungi and phototrophs were identified before and throughout one year after painting two building façades in São Paulo.
Disinfection with hypochlorite and high pressure water jet cleaning of the façades caused reduction of at least 85% in the microbial population.
Paint was applied with or without a biocide formulation (0.
25% w/w) carbendazin, N-octyl-2H-isothiazolin-3-one and N-(3,4-dichlorophenyl)N,N-dimethyl urea.
The biocide reduced fungal colonization up to 10 months after painting on one building.
However after 12 months biocide made no statistically significant difference.
The major fungal contaminant was the genus Cladosporium.
After 10 months Aureobasidium was also associated with black discoloration.
On both the re-painted façades, fungi were detected before phototrophs, contrary to the citations from the literature.
SEM showed that fungal contamination was present not only on the surface, but between the old and new paint films and between old paint and rendering mortar.
Under these conditions building façade details and micro-environment seem to be more important than biocide in controlling fungal growth.

Online publication: 2004-06-27
Classification: Scientific Reports
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/13914