An Experimental Approach to the Study of Moisture Dynamics in Walls

This paper reports on the design of an experimental facility to examine moisture levels in the various components of a building envelope over the course of seasonal weather patterns. Using analytical methods, the pertinent factors in moisture accumulation were identified and the wall panels were built using a range of these factors. In addition to the permeance of the building materials, the effect of solar heating and interior vapor pressure also were studied. In this way, the relative importance of these variables can be compared while at the same time allowing the other factors of actual weather conditions, such as wind and precipitation, to be included as random variables. By using this approach, a realistic appraisal of the relationship between these factors and moisture accumulation can be made. To illustrate the capabilities of this facility, some preliminary data collected the first year are shown and compared to model predictions using the recorded weather conditions. Limitations of the experimental program as well as future research needs are discussed.