With government targets for 1.5m new homes by 2029 and the Future Homes Standard mandating low-carbon performance, modern methods of construction (MMC) offer speed, quality and sustainability benefits. However, barriers to the government's housing targets remain, including financial fragility, skills shortages and compliance challenges under the Building Safety Act 2022.
This article reviews the current state of MMC, explores regulatory developments and highlights the critical role of surveyors in ensuring safety and performance.
Why is there a growing need for MMC
Post-war Britain embraced prefabrication to address urgent housing needs, with the Airoh temporary aluminium bungalow becoming a symbol of rapid innovation. However, legacy issues from poorly executed experiments left a residue of mistrust. The recent RAAC crisis underlined the short life expectancy of some earlier systems, particularly as regards the high numbers of affected school buildings in Essex, which were originally constructed to meet significant demand for school places.
Today's MMC must overcome similar scepticism – but with far higher stakes, including compliance with net-zero carbon targets and the Future Homes Standard 2025.
The UK government defines MMC across seven categories, from volumetric modular systems – Category 1 – to panelised frames – Category 2 – and sub-assemblies. In 2025 MMC accounted for 24% of new-build residential projects, up from 18% in 2024.
Public sector schemes – hospitals, schools and social housing – are driving adoption, while digital integration is now standard: BIM Level 2, digital twins and AI-driven design tools underpin compliance and efficiency.
Benefits of MMC reaffirmed
Evidence continues to support MMC's advantages.
- Programme savings: 30–40% faster delivery than traditional builds.
- Quality and predictability: factory-controlled environments reduce the risk of defects.
- Sustainability: studies show 20–25% lower embodied carbon and significant waste reduction.
- Health and safety: fewer operatives working at height and improved site conditions.
These benefits will, it is hoped, align with the much vaunted (and delayed) Future Homes Standard, which is expected to propose a 75–80% reduction in operational carbon emissions for new homes, alongside low-carbon heating and enhanced airtightness.
The Homes England Annual Report 2023 to 2024: Chair's Forward and Performance Report, refers to a study by KLH Sustainability. The latter compares modular and traditional construction, concluding that modular construction results in an over 45% reduction in material use and over 50% reduction in waste generation.
Barriers and risks
Despite progress, challenges remain.
- Financial resilience: the collapse of major MMC firms in 2024 and 2025 highlights vulnerability to cash flow pressures and inconsistent demand.
- Skills gap: the construction workforce faces a shortfall of 250,000 roles by 2028, with MMC-specific skills in digital design and offsite manufacturing in short supply.
- Regulatory complexity: The Building Safety Act 2022 introduced stringent compliance obligations, including the golden thread of digital information and gateway approvals for higher-risk buildings.
- Assurance and warranties: Schemes such as NHBC Accepts and BOPAS now provide technical validation, but lenders and insurers still demand robust guarantees.
Fire safety and compliance
Post-Grenfell reforms have reshaped the regulatory landscape and MMC projects must now demonstrate compliance through rigorous testing and documentation.
The Building Safety Regulator now oversees all building control in England, and is the building control body for high-risk residential buildings (HRBs). It also oversees HRBs more generally in relation to the in-occupation phase and safety cases issuing building assessment certificates.
Fire performance remains a critical concern, particularly for hybrid systems and imported modular units. Surveyors must scrutinise cavity barriers, fire stopping and certification – lessons reinforced by recent case studies of container-based student housing and modular towers.
In particular, surveyors should refer to the Health and Safety Executive's 2024 RR1203 research report, and CROSS-UK's 2025 1482 report, which describes a fire in a container-based modular building.
Case studies and lessons
Published in February 2024 by the Infrastructure and Projects Authority, the National Infrastructure and Construction Pipeline 2023 provides helpful feedback on some of the benefits of MMC. In particular, the document cites the development of HMP Fosse Way as an example:
'Construction was also approximately 22% faster than a traditional build due to 70% of the project using modern methods of construction (MMC), which resulted in better efficiency, safety, and quality.'
Some aspects of the Fosse Way project may sound familiar – such as the use of over 12,000 pre-cast concrete panels, as well as pre-cast walls, cell windows, internal riser modules and modular plant rooms. All of these were manufactured off site.
However, the adoption of MMC does not mean that fundamental principles such as ventilation, moisture control and thermal bridging can be ignored; they remain non-negotiable. Innovation does not absolve designers from respecting established science.
In the author's direct experience, significant issues can arise from using MMC. Some examples include the following.
- A bespoke dwelling constructed of cross laminated timber (CLT) where inadequate provision was made for waterproofing. The CLT extended below ground level and formed part of the basement retaining structure. Unsurprisingly, the lower parts of the CLT decayed, leading to structural problems as well as dampness. This rendered the house uninhabitable.
- Two new-build schools constructed using hybrid roofing cassettes, with insufficient attention being paid to condensation risks. These roofs failed within a few years of installation.
- The rapid failure of hybrid warm roofs in at least four modular dwellings, plus two further examples in purpose-designed dwellings.
- Inadequate protection of modular school buildings during construction, leading to water entrapment and a risk of decay within roofs and walls.
- Inadequate sub-floor ventilation to a series of timber-framed modular children's centres and classrooms, leading to profound timber decay and the partial collapse of floors.
The role of surveyors
Surveyors are a key part of the regulatory framework of MMC. Their responsibilities include:
- evaluating MMC systems against, for example, NHBC Standards Part 11 and warranty protocols
- ensuring compliance with Future Homes Standard and Building Safety Act 2022 requirements
- advising on risk management, procurement and life cycle performance, and
- applying knowledge of why buildings fail, how materials function and where workmanship could be lacking.
MMC offers a pathway to address housing need and climate goals, but only if underpinned by rigorous professional oversight.
Surveyors must lead in applying technical knowledge, challenging assumptions and safeguarding quality. The physical forces acting on buildings have not changed; our duty is to ensure that innovation respects them.
A version of this article was originally published on 21 October 2021.
Trevor Rushton FRICS is chairman of Watts Group
Contact Trevor: Email
Related competencies include: Building pathology, Construction technology and environmental services, Design and specification
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