Prevalence, Risk Factors and Impacts Related to Mould-Affected Housing: An Australian Integrative Review

Abstract

In response to an Australian governmental inquiry into biotoxin-related illness, the purpose of this integrative review is to bring together the current state of evidence on the prevalence, risk factors and impacts related to mould-affected housing in an Australian context, in order to inform building, housing and health research, practice and policy. The robust integrative review methodology simultaneously sought quantitative and qualitative studies and grey literature from multiple disciplines, identifying only 45 studies directly relating to Australian housing and indoor mould. Twenty-one studies highlight negative health impacts relating to indoor residential mould, with asthma, respiratory, allergy conditions and emerging health concerns for chronic multiple-symptom presentation. The majority of studies reported risk factors for indoor mould including poor housing conditions, poor-quality rental accommodation, socioeconomic circumstance, age-related housing issues and concerns for surface/interstitial condensation and building defects in newer housing. Risks for indoor mould in both older and newer housing raise concerns for the extent of the problem of indoor mould in Australia. Understanding the national prevalence of housing risks and “root cause” associated with indoor mould is not conclusive from the limited existing evidence. Synthesis of this evidence reveals a lack of coverage on: (1) national and geographical representation, (2) climatical coverage, (3) housing typologies, (4) housing defects, (5) maintenance, (6) impact from urbanisation, and (7) occupant’s behaviour. This integrative review was key in identifying emerging housing and health concerns, highlighting gaps in data and implications to be addressed by researchers, practice and policy and acts as a comprehensive holistic review process that can be applied to other countries.

The moisture distribution in wall-to-floor thermal bridges and its influence on mould growth

“…In summer, by using Eqs. (10)(11) and the hygrothermal properties provided by Table 1, the seasonal average of R (denoted as Rave,ts) of uninsulated and insulated WFTB are calculated as 0.0824 and 0.0755 m 2 •K•W -1 , respectively. When the season changes from summer to winter, the Rave,tss increases only by 0.0004 and 0.0005 m 2 •K•W -1 , respectively, which means that the change of seasons has a very limited effect on the thermal performance.…”

“…When the temperature and relative humidity is appropriate (see Fig. 4-a), mould spores will germinate at the surface or inside of the building envelopes [7,[9][10][11]. After the spore germination, the mycelial will continue to grow if the hygrothermal environment is still within an acceptable range.…”

“…The indoor organic pollutants caused by mould can also significantly decrease the service life of building materials and components [6]. Further, mould not only grows on the surface but also germinates and expands inside building envelopes, mainly through condensation within a building form [7][8][9][10][11]. Unfortunately, the negative effects caused by moisture are more apparent in energy-efficient buildings due to some energy-saving methods, e.g., the application of the thermal insulation layer [9].…”

The moisture distribution in wall-to-floor thermal bridges and its influence on mould growth

“…In the summer, by using Eqs. (10)(11) and the hygrothermal properties provided by Table 1, the seasonal averages of R (denoted as R ave,ts ) of uninsulated and insulated WFTB are calculated as 0.0824 and 0.0755 m 2 •K•W -1 , respectively. When the season changes from summer to winter, the R ave,ts s increases only by 0.0004 and 0.0005 m 2 •K•W -1 , respectively, which means that the change of seasons has a very limited effect on the thermal performance.…”

“…The indoor organic pollutants caused by mould can also significantly decrease the service life of building materials and components [6]. Furthermore, mould growth is not limited to the indoor surface; it can easily germinate and expand inside building envelopes, especially where high levels of humidity are likely to occur [7][8][9][10][11]. Unfortunately, the negative effects caused by moisture are more apparent in energy-efficient buildings due to some energy-saving methods, for example, the application of the thermal insulation layer [9].…”