Unlocking MMC Factory Capacity: Turning Downtime into Homes

The UK construction sector has invested heavily in Modern Methods of Construction (MMC) over the past decade. Yet across the country, many MMC factories are operating well below capacity. The capability to deliver high-quality homes at scale already exists — but the pipeline of demand needed to sustain that production remains uncertain.

To explore how this gap could be addressed, CIRIA and Buildoffsite convened a government roundtable, Unlocking Downtime. The event brought together senior representatives from government, housing bodies, local authorities, manufacturers and developers to examine the barriers preventing MMC factories from operating at full capacity — and to identify practical solutions.

The discussion focused on a central challenge: how to convert under-used manufacturing capability into real homes delivered. While the UK faces an ongoing housing shortage and ambitious net-zero commitments, the sector is not yet fully utilising the industrialised capacity already in place.

Participants agreed that the issue is less about technology readiness and more about demand-side barriers, including planning processes, procurement structures and fragmented project pipelines. The roundtable therefore explored how government and industry might collaborate on a short, focused plan to unlock MMC capacity.

The MMC Capacity Gap

Across the UK, a number of factories capable of producing high-quality modular and panelised housing components remain underutilised. In many cases, production lines designed for continuous manufacturing face intermittent demand, creating costly downtime.

This gap reflects several systemic challenges. Planning processes can be slow and inconsistent, procurement routes are often complex or fragmented, and development pipelines frequently operate on a stop–start basis. Together, these factors make it difficult for manufacturers to plan production and scale efficiently.

Yet the opportunity is significant. By making better use of existing manufacturing capability, the UK could deliver more homes, faster and with lower carbon impact, while strengthening domestic supply chains.

Planning and Approvals: Making MMC Easier to Approve

Roundtable participants highlighted planning and approval processes as one of the most significant barriers to wider MMC adoption.

Planning teams are frequently under-resourced, and innovative approaches can sometimes be viewed as an additional risk rather than an opportunity. Participants noted that progress may not require major national reform but rather practical improvements in development management policies and local strategies.

A number of specific challenges were identified:

• Early design freeze requirements can conflict with manufacturing-led approaches
• Planning decisions may prioritise design specification over buildability
• Local authority requirements vary significantly, creating friction for developers and manufacturers

There are, however, encouraging developments. The growing use of “kit-of-parts” design approaches is beginning to evolve into pattern-book style solutions aligned with the Future Homes Standard. Estimates suggest that around 22% of homes now include some MMC elements, much of this in panelised construction.

Several mayoral authorities are already taking a strategic approach to MMC adoption. For example, Greater Manchester has embedded MMC within its net-zero delivery strategy, and six mayoral authorities now have dedicated MMC strategies in place.

The discussion concluded that clearer guidance and more consistent policies could reduce uncertainty and accelerate approvals.

Procurement: Making MMC Easier to Buy

Procurement structures have also changed significantly over time. Earlier MMC projects often involved direct relationships between clients and manufacturers, but many developments are now delivered through contractors operating within large framework agreements.

This shift has created several challenges:

• Skills gaps, particularly around advanced systems such as closed-panel construction
• A tendency for MMC projects to be treated repeatedly as “pilots” rather than normal delivery routes
• Limited capture and sharing of lessons learned from previous projects
• Fragmentation across an estimated 4,000 public procurement frameworks

Participants discussed how emerging policy changes, including the Procurement Act 2023, could enable more innovative approaches to procurement and help create repeatable delivery models.

A key next step identified was the development of practical procurement actions — including templates, routes and specifications that could support consistent MMC deployment.

A National Shared Capacity Pilot

Perhaps the most significant proposal emerging from the discussion was the concept of a National Shared Capacity Pilot.

The aim would be to test a model in which multiple clients coordinate demand to utilise existing factory capacity more efficiently. By aligning pipelines of housing delivery with manufacturing capability, the pilot could demonstrate how to reduce downtime and accelerate output.

Potential starting points discussed included regional pilots in areas such as Liverpool or Manchester, potentially working with Mayoral Strategic Authorities.

Participants also noted opportunities to align the pilot with existing funding programmes and national initiatives, including:

• The National Housing Bank, which aims to support delivery of up to 300,000 homes annually
• The Homes England Affordable Homes Programme (£39 billion)
• Local growth plans and regional regeneration programmes
• Innovation initiatives such as the Made Smarter programme

Clear performance metrics would be essential to evaluate the pilot’s success. These could include:

• Cost and programme certainty
• Quality and building safety
• Whole-life value and operational performance
• Carbon reduction and net-zero alignment
• Economic impact across regional supply chains

From Discussion to Delivery

The roundtable concluded that unlocking under-used factory capacity requires coordinated action across planning, procurement and pipeline visibility. Developing a National Shared Capacity Pilot could provide a practical mechanism to bring these elements together — testing how coordinated demand, policy improvements and procurement innovation might accelerate both factory utilisation and housing delivery.

The intention is to refine these proposals further and engage with government and publicly funded bodies during 2026, with the aim of turning the concept into a deliverable programme.

A Collaborative Next Step

The roundtable demonstrated strong cross-sector interest in addressing the MMC capacity gap. Participants agreed that the opportunity now lies in translating discussion into a shared plan that aligns policy, industry capability and housing need.

If successful, this work could help ensure that the UK’s investment in industrialised construction is fully realised — turning factory downtime into homes delivered.