The determination of conditions for microbial growth in the Crawlspaces

Temperature, relative humidity, pressure difference across the floor and microbial concentrations were investigatedin the four buildings which had either concrete floor (1 piece) or wooden floors (3 pieces) and crawlspaces.The temperature followed the outdoor temperaturein the crawlspaces having wooden floors. The relativehumidity in all the crawl spaces was continuously for a month at least 75 %. The moisture and temperatureconditions were favorable for microbial growth and several moisture indicating microbes were analyzed in crawlspaces and in indoor air. The crawl spaces were positively pressurized when compared to indoor spaces. Thus, the convective flow via the air leakages across the floor was possible and the microbes and their gaseousmetabolites could be transported to the indoor air.