Dampness remains a pervasive challenge in building construction, particularly within tropical and humid environments such as Nigeria. This article provides an intensive analysis of the role, implementation challenges, and consequences of inadequate damp proof membranes (DPMs) in Nigerian buildings. DPMs are critical barriers designed to prevent the ingress of moisture, predominantly through rising damp, from the ground into the building's superstructure. While their importance is globally acknowledged, their effective application in Nigeria is frequently hampered by a confluence of factors including insufficient awareness, cost-cutting measures, substandard materials, and poor installation practices. This paper explores the technical significance of DPMs, delineates the specific context of dampness in Nigerian construction, identifies the prevalent challenges, and discusses the farreaching implications for structural integrity, occupant health, and economic sustainability. Recommendations for enhanced policy, education, quality control, and professional practice are proposed to improve DPM efficacy and foster more resilient and healthy built environments in Nigeria.