Empirical Analysis of the Impact of Sandcrete Block Quality on Structural Integrity of Low-Rise Buildings in Enugu State

Sandcrete block quality directly determines the structural integrity of low-rise masonry buildings, and empirical investigation of this relationship in Enugu State, South East Nigeria, provides evidence for strengthening quality enforcement. This study empirically analysed the relationship between sandcrete block quality (as measured at production sites) and structural defect rates in completed low-rise residential buildings in Enugu State. A two-phase mixed-methods design was employed. In Phase 1, sandcrete block samples were collected from 40 active block production sites across Enugu North, Enugu South, and Nkanu East, and tested for compressive strength, water absorption, and dimensional accuracy per NIS 87:2004. In Phase 2, 120 recently completed residential buildings (within 5 years) were inspected for structural defects, and the block production sources were traced through contractor interviews. Pearson correlation and binary logistic regression were used to assess the block quality-structural defect relationship. Results showed that 58% of sampled blocks failed to meet minimum compressive strength requirements. Building inspection showed that structural defect incidence (wall cracking, foundation movement, and column distress) was significantly correlated with below-standard block compressive strength (r = -0.68, p < 0.001). Buildings constructed with blocks from non-compliant production sites had 4.6 times greater odds of significant structural defects than those using compliant blocks (OR = 4.6, p < 0.001). The study concludes that block quality enforcement is the single most impactful structural safety intervention available in Enugu State's residential construction sector. Keywords: sandcrete block quality, structural integrity, low-rise buildings, Enugu State, compressive strength