Benefit evaluation for off‐site production in construction

TLDR

Off‑site production is often justified by cited benefits, yet industry assessments are inadequate, overlooking cost factors such as site facilities, crane use, rectification, and soft issues like health and safety and process benefits. The study contends that without a holistic, value‑based evaluation, off‑site production adoption will remain limited. The authors critique existing evaluation methods that consider only material, labour, and transport costs, neglecting other cost items. Case studies show that evaluations focus narrowly on direct costs, ignoring broader cost and soft‑issue benefits that are actually significant advantages of off‑site production.

Abstract

Evaluating to what extent a component or building system should be produced off‐site is inadequate within the industry. The potential benefits of off‐site production (OSP) are commonly cited when justifying an OSP approach, yet holistic and methodical assessments of the applicability and overall benefit of these solutions, to a particular project, have been found to be deficient. Common methods of evaluation simply take material, labour and transportation costs into account when comparing various options, often disregarding other cost‐related items such as site facilities, crane use and rectification of works. These cost factors are usually buried within the nebulous preliminaries figure, with little reference to the building approach taken. Further, softer issues such as health and safety, effects on management and process benefits are either implicit or disregarded within these comparison exercises. Yet it is demonstrated that these issues are some of the most significant benefits of OSP. A series of case studies demonstrated that evaluation focus is almost solely on direct material and labour costs of components, without explicit regard for the wider cost or soft issue implications of OSP on a project. The paper argues that until evaluation is more holistic and value‐based rather than cost‐based, OSP uptake in construction will be slow.