Evaluation of Damp-Proofing Methods Used in Ground-Floor Buildings in Ibadan, Oyo State

Rising damp is a pervasive building defect in ground-floor residential and commercial structures in Ibadan, South West Nigeria, affecting structural durability and occupant health. This study evaluated the types, application methods, and effectiveness of damp-proofing measures used in ground-floor buildings in three local government areas of Ibadan: Ibadan North, Ibadan South West, and Egbeda. Field inspection of 90 ground-floor buildings was conducted, assessing the presence, type, and condition of damp-proof courses, damp-proof membranes, and surface treatments. Moisture content readings of external walls were taken using a digital moisture meter at 300mm above floor level. Building professionals and artisans (n = 45) were interviewed about their damp-proofing knowledge and practices. Results showed that only 31% of inspected buildings had an identifiable damp-proof course installed, and of these, 48% showed evidence of damp-proof course bridging or failure. Bituminous felt was the most common damp-proof course material, but it was improperly lapped or sealed in 62% of cases. Wall moisture content exceeded the acceptable threshold of 20% in 67% of inspected buildings, confirming widespread dampness problems. The study concludes that damp-proofing practice in Ibadan ground-floor buildings is technically deficient, driven by poor artisan knowledge and absence of quality inspection. Training workshops for artisans and mandatory damp-proof course inspection at foundation stage are recommended.

Keywords: damp-proofing, rising damp, ground-floor buildings, Ibadan, moisture content