MMC Construction

The concept of Modern Methods of Construction (MMC), introduced by UK government bodies, presents a fresh opportunity to innovate within the building industry. While its precise definition is still emerging and actively debated amongst industry professionals, this ongoing discussion is a crucial step towards establishing a shared understanding and unlocking the full potential of modern construction techniques.

modern construction techniques

What is MMC?

MMC Construction is a collective term used to describe a number of modern construction techniques which differ significantly from conventional building like cavity walls.

Building systems which are currently classed as MMC construction usually involve off-site manufacturing of components or entire modules. Once transported to site, they are assembled using efficient techniques to streamline the building process.

Historical Background

In 2003, Homes England (previously known as the Housing Corporation) published a construction classification system that has been adapted and developed by the UK government.

ICF was classed under “Non Off-Site manufactured Modern Methods of Construction”, however there is no clear agreement to this classification.

While Insulated Concrete Formwork (ICF) has been in use since World War II, it is still considered to be an MMC construction system. It certainly has all of the advantages of modern construction techniques but virtually none, of the disadvantages.

MMC Advantages

reduce costs

MMC off-site manufacturing allows for concurrent production and site preparation, significantly reducing on-site construction time (potential time savings of 10% to 50%).

Faster project completion can lead to earlier revenue generation for developers and reduced reliance on weather-dependent on-site activities.

MMC construction allows factory-controlled environments to enable consistent quality, precision, and adherence to standards with reduced errors and defects and third-party inspection and certification.

ICF systems inherently streamline the construction process, leading to a notable decrease in the amount of on-site labor required.

Simplicity of installation: ICF blocks are lightweight and designed for easy stacking, reducing the need for highly skilled masons or carpenters for initial wall erection. This allows for a smaller, more efficient crew.
Reduced Finishing Work: The smooth surface of ICF walls often provides a ready substrate for finishes, whether it’s drywall, stucco, or siding. This can reduce the amount of prep work and the time required for finishing trades compared to uneven concrete or traditional framed walls that might require more extensive leveling or furring out.
Faster Learning Curve: While some initial training is beneficial, the repetitive nature of ICF installation means that even less experienced workers can quickly become proficient, further reducing reliance on highly specialized and potentially more expensive labor.

Material waste is a significant cost in traditional construction, but ICF systems are designed to minimize this through Pre-manufactured Components. ICF blocks are manufactured off-site to precise dimensions, reducing the need for on-site cutting and trimming of lumber or other framing materials. This eliminates the scrap generated from traditional stick-built framing.

Lower Site Overheads Associated with Shorter Project Durations and Reduced Site Labour. This point highlights a cumulative benefit of the previous two, where the efficiencies gained translate into significant savings on overall project overheads:

Reduced Rental Costs for Equipment: A shorter construction period means less time that heavy equipment (e.g., scaffolding, concrete pumps, lifts) needs to be rented, leading to substantial cost savings.
Lower Utility Costs: With less time spent on site, there’s a reduction in the consumption of temporary site utilities such as electricity for lighting, heating, and power tools, as well as water.
Fewer Site Management Hours: Project managers, supervisors, and administrative staff spend less time overseeing a shorter project, freeing them up for other tasks or reducing their overall hours billed to the project.
Reduced Security Costs: A shorter project duration translates to less time that the site needs to be secured against theft or vandalism, reducing costs for security personnel, fencing, or monitoring systems.
Faster Return on Investment: For developers, completing a project sooner means they can sell or lease the property earlier, generating revenue and providing a quicker return on their investment, which is a significant financial benefit.

Flexibility

MMC construction provides a safer working environment as more work is conducted in a controlled factory setting, reducing risks associated with working on site.

Reduced environmental impact through decreased material waste, fewer site deliveries, and lower carbon emissions from transportation.

Increased use of sustainable materials like timber in some modern construction techniques.

MMC methods offer significant design flexibility, especially with advancements in technology like BIM (Building Information Modelling).
Modular units can be adaptable and tailored to various project needs.
Hybrid approaches combining volumetric and panelized systems offer design versatility.

MMC Disadvantages

Limitations

Standardization in some MMC approaches limits architectural design and aesthetic choices compared to traditional methods.

Transportation constraints can lead to limitations in room sizes.

Transporting large, prefabricated modules or panels is complex and costly and there is potential for damage during transportation.

Poor consideration of tolerances during design and manufacturing can lead to issues with the fit of components during on-site assembly, potentially affecting structural integrity and durability.

Long Term Issues

The fire performance of modern construction techniques is a crucial consideration, and it varies significantly depending on the specific MMC category and the materials used. It’s important to understand that some MMCs, particularly those using timber or composite materials may be problematic. Fire risk assessments and the use of appropriate fire protection measures are essential.

The long-term durability and performance of some MMC construction materials and techniques is relatively unknown.
Future adaptability and maintenance of MMC buildings can be very difficult.
Recycling of materials used in MMC may be very difficult and negatively affect the analysis of the building’s environmental impact.