When most people hear “MMC,” their minds often jump straight to prefabrication or modular construction. However, modern methods of construction span a wide spectrum of techniques and innovations. We’ve seen firsthand that many professionals aren’t aware of the distinct categories that make up MMCs, and why this matters. In this article, we’ll explore the seven-category MMC definition framework developed by industry experts, providing clarity on how different approaches can impact your projects.
The MMC definition framework is designed to bring order to the evolving field of construction innovation. Developed by the MHCLG Joint Industry Working Group on MMC, with input from organisations such as Buildoffsite, Homes England, NHBC, and RICS, this framework categorises methods into seven distinct areas. Its purpose is twofold:
This framework also considers factors such as building typology (ranging from houses to high-rise apartments) and material genres (from mass engineered timber to concrete), ensuring a comprehensive view of modern construction practices. Click the link below to download the official guide on MMC categories.
Category 1: Pre-manufacturing (3D Primary Structural Systems).
Category 1 focuses on a systemised approach using three-dimensional volumetric construction. This involves producing complete 3D units in a controlled factory environment before installing them on-site (often known as Modular). These units can vary from a basic structural chassis to fully finished modules that include internal and external finishes, as well as services.
This category underlines the potential to drastically reduce on-site construction time by shifting a significant amount of work into a controlled factory setting.
Category 2: Pre-manufacturing (2D Primary Structural Systems).
Category 2 is all about flat-panel systems. Here, pre-manufactured panels serve as the basic building blocks; walls, floors, roofs, that are later assembled on-site. This method generally involves less on-site assembly complexity than full volumetric systems.
Category 3: Pre-manufacturing Components (Non-systemised Primary Structure).
Moving away from systemised assemblies, Category 3 focuses on pre-manufactured structural components. These include load-bearing beams, columns, slabs, and even sub-structure elements like ring beams and pile caps. They are manufactured off-site but are not part of a complete system.
This category allows for a high degree of customisation, enabling designers to mix and match components to meet unique structural demands.
Category 4: Additive Manufacturing.
Also known as 3D printing, this approach can produce both structural and non-structural components directly at the worksite or in a factory setting.
Category 5: Pre-manufacturing (Non-structural Assemblies and Sub-assemblies).
In Category 5, the focus shifts from primary structural elements to non-structural assemblies. This includes modular pods for bathrooms and kitchens, facade assemblies, roof cassettes, and even integrated M&E (mechanical and electrical) systems.
This category showcases the potential to offload a significant portion of on-site work to the controlled environment of a factory.
Category 6: Traditional Building, Product-Led, On-Site Labour Reduction.
Category 6 does not involve pre-manufacturing in the traditional sense but focuses on optimised building products designed to reduce site labour. These are often large-format components such as walling or roofing products that are pre-cut or engineered for ease of assembly. A perfect example of this would be ICF blocks that allow for quick construction of reinforced concrete structures, providing insulation in-situ.
Category 7: Traditional Building, Process-Led, On-Site Labour Reduction.
Finally, Category 7 emphasises innovations in the construction process itself. Rather than manufacturing components off-site, this category focuses on improving on-site efficiency. Techniques include digital planning, BIM-connected workflows, augmented reality (AR/VR) for worker augmentation, and even the use of robotics and drones.
Why This Matters.
Modern Methods of Construction are far more than just prefabrication. With a robust seven-category framework that covers everything from 3D volumetric systems to digital on-site process innovations, MMC offers a variety of approaches that can be tailored to meet the diverse needs of today’s construction projects. As professionals, it is vital to challenge existing perceptions and consider which categories might be applicable, or even revolutionary, for the projects you work on. Embracing this framework not only promotes efficiency and innovation but also paves the way for more sustainable, cost-effective construction practices.