Evaluating the Defect Performance of Panelized and Modular Systems

Introduction

Modern methods of construction (MMC) are repeatedly embraced by nations as opportunities to resolve housing availability crises, owing to conjectures that they offer economic advantages, including superior quality performance. However, such arguments lack experimental substantiation in the house construction context. Consequently, end users lack the information required to make informed decisions.

Methods

This article contributes to the fulfilment of the aforementioned knowledge void by informing end users and governments of the defect performance of four different MMC systems (CS1-4). This research includes six case studies (CS) involved in a unique house-building research experiment managed by a single construction contractor on an individual building plot, including the following house construction systems: CS1: light gauge steel panelized; CS2: concrete panelized; CS3: timber frame modular; CS4&5: two identical steel frame modular systems, and CS6: traditional construction system (TCS). Therefore, the defect performance of two duplicate MMC is also comparatively analysed. The research method includes a review of published works, investigations of the house drawings and defect data, and construction staff surveys.

Results

All MMC resulted in a higher or similar number of defects to the TCS. Some MMC (CS1&4) generated more structural cracks than the TCS. Modular systems (CS3&4) displayed more latent defects than the TCS. The identical MMC systems (CS4&5) produced dissimilar numbers and types of defects.

Conclusions

Scholars typically argue that MMC are less cost-efficient and have allegedly superior quality performance than TCS. However, as shown in this article, MMC can result in a similar or higher number of defects, which vary in type and consequence. This revelation is important in the context of inadequate durability and whole-life quality performance measurements of MMC, which are likely to impact the desirability and sustainability of MMC.