Moisture Movement (Wicking) within Gypsum Wallboard

摘要

Gypsum wallboard with repeated or prolonged exposure to water or excess moisture can loseits structural integrity and provide a growth medium for biological contaminants. Poorly sealedbuildings, leaking or failed plumbing systems, or improperly constructed HVAC systems can allcontribute to water and moisture problems. Gypsum wallboard readily absorbs moisture throughdirect contact with standing water and differences in water vapor pressure. Regular gypsumwallboard sample sections were hung vertically and exposed to a continuous source of standingwater 1.3 cm in depth. Both water absorption (measured in percent moisture content) andvertical movement (wicking height) were monitored within the wallboard over several days. Themoisture content measurements revealed a water movement pattern similar to paperchromatography. A leading edge of relative high percent moisture content (～ 20%MC) movedupward along the width of the wallboard. The immersed portion of the wallboard maintained amoisture content level ≥ 20%. Between the leading edge and immersed portion of the wallboardwas an area of moderate moisture content (～ 12%MC). Water wicked to a height of 15 cmwithin the first three hours of testing after which the rate continued asymptotically appearing toreach a maximum height by day 16.