Investigation and assessment of moisture and mould growth in buildings
Summary
Moisture and mould growth destroy buildings, are insanitary and moulds can be injurious to the health of the building users. It is therefore important to investigate if moulds are present or conditions that cause and promote moisture and mould growth exist.
This publication describes a tool for investigating and assessing the conditions of buildings. The introduction of the publication informs the reader in general about moulds and their health effects. The following part of the publication presents methods for investigation of buildings. Forms have been developed intended as an aid during the investigation. They are attached as appendices. An outline of recommended aids and protection for investigating engineers and building users are presented.
The following part of the publication presents a number of measuring instruments and measuring methods as well as the background for criteria and assessments of the significance for moisture and mould growth in buildings. It is a precondition, though, that the investigating engineer possesses fundamental knowledge of building technology and moisture transportation and accumulation.
Based on the checklist in this publication which lists causes of moisture and mould growth as well as the guideline assessment criteria, investigating engineers can, with great certainty, establish reasons for the presence of moisture and mould growth in the examined building. Moreover, the results of the overall investigation can serve to assess the conditions affecting human health.
The investigation and assessment
It is recommended that an inspection is carried out in several steps. When an agreement about the investigation and its goals has been reached, the first step consists of interviews and a visual inspection (Walk through) to uncover the presence of moisture, moulds and dust often supplemented by some moisture measurements.
The next steps may involve taking samples of the dust and mould growth and possibly exploratory measures in constructions to perform measurements of moisture, ventilation and some other building conditions including drainage and soil conditions. Analyses of dust and mould growth may be included that are to be used to assess specific health effects caused by exposure to moulds. The most important measuring methods and guidelines for assessing the results are described for moisture, moulds, ventilation and other building conditions, including drainage and soil conditions.
Guidelines for assessment of the measuring results, assessed individually and as a whole present four categories of risk factors. However, the significance of the measured values or risk factors will always be an individual assessment and there are no official limits for what is considered acceptable or what is considered injurious to human health. Conditions and risk factors that in this publication are described as a high or abnormal risk for mould growth or risk for human health effects are pragmatically based on both laboratory results, statistical surveys of the exposures and epidemiological studies combined with clinical experience.
Before expensive and complicated measurements are initiated, it is recommended that there is a plausible reason such as knowledge about water damage and mould growth or results from a general building inspection or the presence of complaints or symptoms of illness that might be related to the presence of moisture and moulds.
Though the publication’s main subject is moulds in buildings, special cases are described where water systems are suspected of being infested with Legionella bacteria or specific odours that indicate growth of actinomycetes like for instance Streptomyces. Other sources of bacterial infections should be left to investigators of the environment and occupational health or health inspectors, who can organize and carry out the necessary inspection. The publication contains an index listing the guidelines concerning specific problems related to the subject.
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