Fungal growth on different insulation materials exposed to different moisture regimes

Commercially available paper, flax, glass wool and rock wool insulation materials were tested for sensitivity to moisture and the ability of fungi to grow on them under different moisture regimes. Three levels of moisture were used, ambient, simulated rain and water holding capacity. After wetting, the materials were inoculated with a mixture of fungi and incubated at 26°C in boxes with high moisture levels for 4 weeks. The greatest degree of fungal growth was observed on paper and flax insulation materials initially conditioned to ambient moisture levels. Paper and flax insulation were strongly affected by moisture, with all treatments showing losses in dry mass of approx. 20%, except for paper subjected to simulated rain treatment in which the loss was 39%. Glass and rock wools were not sensitive to moisture and were resistant to fungal degradation, showing only traces of fungal growth and minimal loss in dry mass over 4 weeks.