Alternatives for Minimizing Moisture Problems in Homes Located in Hot, Humid Climates: Interim Report
An effort was undertaken to examine manufactured homes in the Gulf Coast area, gather information on condensation-related moisture problems in those homes, and determine the contributing factors to those problems. Building scientists gathered data from 70 homes with and without moisture problems. A thorough literature review, examination of the data, and neural network analysis of the data were used to evaluate and prioritize the significance of twelve potential contributors to moisture problems, in terms of their impact in causing such problems. This document reports on the findings of this research effort.
Significantly, the results of the neural network analysis indicated that 62% of the problems could be explained by a number of the identified contributors. These results, in combination with other data analysis and the literature review helped to prioritize the full list of contributors in terms of their impact on moisture problems and to and classify them into three groups. In order of decreasing significance, these were found to be:
- Pressure imbalances, including those caused by imbalances in the distribution of conditioned air, duct leakage, and shell leakage.
- Vapor retarders and air barriers as a complete system, including the walls (wall air barriers and vapor retarders), floor (bottom board and ground cover) and ceiling (ceiling air barrier and vapor retarder).
- Occupant comfort, which is affected by a combination of indoor temperature and humidity levels.
It was also concluded that statistical analysis and modeling can play a supporting role in identifying major causes of condensation-related moisture problems but cannot fully explain the nature and source of moisture problems. As a result of this prioritization, further work is recommended that will focus on the three moisture problem contributor areas identified above, with an emphasis on the first two: pressure imbalances and vapor retarders/air barriers. This work will require testing and evaluation of unoccupied homes and building subsystems under controlled conditions. It will produce specific guidelines for the minimization and remediation of moisture problems for manufacturers, installers, service personnel, and homeowners of manufactured homes in the hot, humid climate of the Gulf Coast region.