Humidity Control in Outboor-Air-Ventilated Crawl Spaces in Cold Climate by Meansof Ventilation, Ground Covers and Dehumidification

摘要

This study shows that acceptable moisture condition in cold climate outdoor-air-ventilated crawl spaces may be achieved by the optimal selection of ground covers and ventilation. The objectives were to find out which ground covers are suitable to use in relatively warm or cold crawl spaces of buildings and houses, which material properties of the ground covers are important for the reduction of crawl space relative humidity and for increasing temperature, to determine optimum air change rates, and to test dehumidification. The field measurements were carried out in five crawl spaces, where alternative ventilation solutions, ground covers and dehumidification were tested. The measured data were used to develop a new crawl space model in a modular simulation environment, which was used for parametric simulations, where air change rates and ground covers were varied in relatively warm or cold crawl spaces. The model took into account ground moisture evaporation, moisture flows carried by ventilation and moisture transfer in the base floor and ground cover. The acceptability of moisture conditions was assessed by mould growth analyses based on the cumulative time of wetness and the time needed to start mould growth.