Fukt, trä och mögelväxt – en översikt över litteratur inom området

Preventing mould growth on building materials during construction requires understanding the conditions under which mould can grow. This study conducted an inventory of literature published in the field of moisture, wooden material, and mould growth, selected, documented and categorised relevant literature, and summarised the state of current research. The study is part of a bigger project working to produce a handbook for the moisture-proof production of wooden buildings. The criterium for selecting literature was whether it could provide information on the conditions under which mould growth can occur on wood and wood-based materials during the production stage. This information mainly covers limit values for humidity and temperature, how long these limit values can be exceeded without mould growth, and whether there are differences between different wood materials and between different wood-based products. Both laboratory tests and field studies are included in the material. Most published laboratory studies have been performed under high relative humidity (RH), very favourable to mould growth. Often in these conditions, mould growth begins within one week on all wooden material. Mould growth at lower, less favourable humidity conditions is less studied. However, there are indications that the lowest RH at which mould can grow varies between different qualities of wood. The laboratory studies use different methodologies, and it is not easy to compare results and make general conclusions to achieve the purpose of this study. For example, only discolouring growth is studied, resulting in misleading interpretations, as there may be extensive growth on a material without being visible to the naked eye. Outdoor field studies were evaluated first after several months. The results are difficult to apply to the construction of buildings, as these are not exposed for such long periods without weather protection. Additionally, the field studies only considered the development of discolouring growth. The report also summarises several studies performed at RISE using the same methodology. Some are yet unpublished. More information about the relationship between moisture, temperature, wood material, etc. can be obtained by additional analysis of the results from these studies