Salinity-induced building deterioration under low-level salinity conditions: a case study from Coastal Lagos, Nigeria

Purpose This study establishes an empirical relationship between observed building defects and soil salinity levels in coastal Lagos, Nigeria and evaluates whether low-level salinity conditions (EC < 2 dS/m) contribute to significant building deterioration in tropical coastal environments. Design/methodology/approach Sixty-one buildings were surveyed across three environmental zones. Soil salinity was measured in situ using electrical conductivity (EC), and building defects were assessed through structured visual inspection. Findings Measured EC values ranged from 0.55 to 1.92 dS/m. Buildings near the Atlantic Ocean exhibited significantly greater defect prevalence (84%) than near the lagoon (17%) and inland (0%). Soil salinity correlated strongly with defect frequency (Spearman's rs = 0.83, p < 0.001), and multiple regression identified soil salinity as the most significant predictor of defect occurrence (β = 3.944, p < 0.001), independent of building age. Practical implications The results inform site-specific salinity assessment protocols and durability-based design guidelines for coastal construction in the Global South. Originality/value This study provides among the first field-based empirical evidence linking measured soil salinity to observable building pathology in a West African coastal megacity, demonstrating that even low-level salinity can drive significant deterioration when combined with moisture exposure and substandard construction practices.