Quality in construction as a system: theory of defects, variability, and “hidden defects”

Abstract

The article examines quality in construction as a stochastic system in which defects arise not only as a result of noncompliance with tolerances, but also as a consequence of process variability and disruptions in the organization of technological and information flows, generating the phenomenon of “hidden defects.” Based on a dataset from monitoring and construction audit of 48 monolithic frame-type facilities with analysis of more than 120,000 indicators, an expanded classification of defects is proposed, taking into account latency and the temporal lag of manifestation, as well as integral metrics for continuous risk assessment, including a hidden defect index. It is shown that the largest share of deviations relates to concrete works (34.27%) with signs of repeatability of violations, whereas insulation operations are characterized by maximum instability and the highest proportion of critical defects, forming a disproportional threat profile. Zones with the highest probability of defect omission are identified: engineering systems and roofing, where a significant portion of violations manifests during operation and is accompanied by high P_miss values. Statistical analysis of concrete strength demonstrates that exceeding mean values over design values does not compensate for the increase in variance that reduces reliability, especially for high-grade mixes. Economic modeling confirms a nonlinear increase in the cost of defect remediation over time, reaching more than hundredfold multipliers for waterproofing, which substantiates the priority of preventive management of variability and instrumental-digital monitoring compared to ex post control.