Investigation into a Drying System for Residential Walls
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Date
2010-04-13
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Abstract
History has shown that residential structures are likely to experience water problems over the life of the building e.g. wind-driven rain, construction failure, design failure etc. Once inside the structure, water can support fungal growth which can potentially lead to structural degradation and mold. Research has shown that ventilation is the best method to remove unwanted water in the home; however, water located inside of residential wall cavities can be difficult to remove.
The risks associated with trapped water inside of wall cavities can be minimized by introducing air. In this research, compressed air is attached to the wall cavity of a wall model to create air flow and remove water. Several experiments were conducted to both investigate the response of the wall model to compressed air, and to investigate water loss. Air velocity was monitored to investigate air circulation in the wall model; the results indicate that as the distance from the air source increased, the rate of circulation decreased. A series of water loss tests were also made by placing water in the center cavity, and in direct contact with building materials. Observations indicate that insulation, pressure, and time, influence the amount of water removed. With no insulation in the wall model and at 10 psi, 100 % of the water was removed in four hours. With insulation and at 20 psi, 93 % of the water was removed in four hours, and the remaining water was observed to be at the bottom of the wall model. To increase circulation at the bottom, and remove the remaining water, air tubing was added to the wall model. Eight separate tubing arrangements were chosen to observe water loss at 20 psi, with insulation, and over a four hour period. The results are similar, 93 % of the water was removed at 20 psi; albeit, using a lower volume of compressed air. Finally, a hole was cut out of the wall model to provide a path for water and moist air to escape. Observations were made with insulation at 10 psi, 20 psi, and 30 psi. Results indicate that 95 % of the water was removed from the wall model; furthermore, there was no difference in water loss with respect to pressure. Time was also evaluated for each test mentioned above, and the results are similar: most of the water removed over the four hour period was achieved during the first hour.
The results of this research indicate that by introducing air, water can potentially be removed from residential walls, and the risks associated with trapped water can be minimized. More research is needed to investigate a proactive drying system for residential walls.
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Keywords
Building Envelope, Wall Drying, Residential Walls, Wall Cavity
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Degree
MS
Discipline
Wood and Paper Science
