34th Annual Conference of the International Group for Lean Construction (IGLC 34) - Singapore, Singapore - 2026

https://doi.org/10.24928/2026/0258

Minimizing rework in offsite construction: error propagation analysis and quality control

Baseel Andres Ammar1, Haitao Yu2, Moslem Sheikhkhoshkar3 & Farook Hamzeh4

1MSc Student, Civil and Environmental Engineering Department, University of Alberta, Edmonton, Canada, [email protected], orcid.org/0009-0008-3650-619X
2Research and Development, Landmark Group of Companies Inc., Edmonton, Alberta, Canada, [email protected], orcid.org/0000-0002-7798-4867
3Visiting Scholar, University of Greenwich, School of Engineering, London, UK, [email protected], orcid.org/0000-0001-9067-2705
4Professor, Civil and Environmental Engineering Department, University of Alberta, Edmonton, Canada, [email protected], orcid.org/0000-0002-3986-9534

Abstract

Offsite construction (OSC) is increasingly used to enhance productivity, quality, and schedule reliability through industrialized, standardized production processes. However, OSC systems remain susceptible to local execution errors that propagate across interconnected production stations, resulting in rework, delays, and waste. This research examines error propagation within an off-site wall manufacturing line by applying lean principles and techniques. An explanatory case study methodology integrates both qualitative and quantitative approaches. Gemba walks, and a Five Whys root cause analysis was conducted to identify recurring quality defects at stud locations where nails were missing. Subsequently, statistical analysis compared design and as-built dimensions of wall panels to quantify absolute and percentage errors originating from framing and nailing operations. The cumulative impact of these errors was assessed against allowable tolerance limits to determine the likelihood of defects at downstream stations. Findings demonstrate that minor geometric deviations introduced at upstream stations accumulate and surpass tolerance thresholds, substantially increasing defect rates as production advances. These results underscore the necessity of quality-at-the-source practices and intermediate quality checks in OSC systems. This study advances lean construction knowledge by providing empirical evidence of station-level error propagation and recommending targeted remedial actions to improve production flow stability and built-in quality.

Keywords

Offsite construction, lean production, error analysis.

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Reference in APA 7th edition format:

Ammar, B. A., Yu, H., Sheikhkhoshkar, M. & Hamzeh, F.. (2026). Minimizing rework in offsite construction: error propagation analysis and quality control. In Hamzeh, F., Poshdar, M., & Garcia-Lopez,, N. P. (Eds.), Proceedings of the 34th Annual Conference of the International Group for Lean Construction (IGLC 34) (pp. 862–874). https://doi.org/10.24928/2026/0258

Shortened reference for use in IGLC papers:

Ammar, B. A., Yu, H., Sheikhkhoshkar, M. & Hamzeh, F.. (2026). Minimizing rework in offsite construction: error propagation analysis and quality control. IGLC34. https://doi.org/10.24928/2026/0258

 

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