IN-PERSON London. Section A

Abstract

Prefabrication of modular building components may reduce construction time and cost. Prefabrication in a controlled factory setting may also improve energy performance, worker safety and housing affordability. Yet, barriers remain to acceptance of prefabricated modular construction in the U.S. including the lack of industry standardization, added logistics and restrictive financing. As a result, modular construction accounts for only 5% of the U.S. commercial construction market. This study compares the capital and operational performance of 50 modular multifamily projects to 150 comparable site-built projects in four cities at the forefront of the U.S. affordable housing crisis. Results suggest that the energy performance of building components in modular multifamily construction exceeds the performance of those in site-built construction. Although few differences were observed between the types of materials and equipment used in either modular or site-built multifamily construction, the installation quality in modular construction appeared to be better. While the post-occupancy energy performance (kW/m2/year) of modular and site-built multifamily buildings were similar, occupant density was 30% higher in modular buildings. When normalized for this difference, the energy performance of modular multifamily construction was found to exceed that of site-built construction. The most significant advantage of modular construction is schedule savings. Modular buildings in this study were completed 25% faster on average when compared to site-built buildings. Modular construction was found to be cost-competitive with site-built construction. Modular construction, however, requires transportation of building assemblies, limiting the distance between factory and site. Materials for modular construction must be purchased several months ahead of production and require large, upfront deposits. As a result, many commercial lenders are reluctant to fund modular projects.