Assessment of Mould Risk in Low-Cost Residential Buildings in Urban Slum Districts of Surakarta City, Indonesia

Abstract

Prolonged exposure to indoor dampness in dwellings triggers excessive mould, causing health problems for residents and damage to building structures. This study investigated dampness and mould growth in low-cost dwellings in the slum districts of Surakarta, Indonesia. A VTT mould growth model predicted mould risk in 17 dwellings by employing a set of time-series data of indoor air temperature and relative humidity (RH). Interviews were conducted with 11 houses to understand the residents’ perceptions and lifestyles related to mould risk. The daily average dampness (RH > 80%) ranged from 2.2 to 12.3 h. Low-cost dwellings with plywood board walls had a high risk of cumulative mould growth. Statistical correlation analysis revealed that volumetric heat capacity was significantly positively correlated with mould growth at higher percentiles (75th and 97.5th). Thus, dwellings with smaller volumes and plywood board walls were more susceptible to moulding. Moreover, the majority of the participants expressed dissatisfaction with indoor air quality owing to the presence of unpleasant odours from sewage and dampness, which coincided with their perception of inadequate air ventilation. This study provides a reference for developing standard guidelines for building and upgrading dwellings in Indonesia, focusing on assessing and mitigating mould risks and ensuring moisture safety.