96.The suite of Approved Documents published by the Ministry of Housing, Communities and Local Government set out how builders can meet the building regulations. They provide general guidance on expected performance of materials and building work and provide examples and solutions on how to achieve compliance but do not include any specific guidance on MMC. The Approved Documents also set out safety standards and energy performance targets for all building types. The Interim Report of the Independent Review of Building Regulations and Fire Safety, led by Dame Judith Hackitt, commissioned by the Government following the fire at Grenfell Tower criticised the current suite of Approved Documents and said they are not user-friendly:
The Approved Documents are not produced in a user-friendly format. The current format of covering each requirement (fire safety, thermal insulation, noise abatement, etc.) in separate sections leads to multiple, separate specifications for overlapping or common elements of a building, with no easy means for these to be integrated into a single, compliant specification.
97.In December 2018 the Government published its implementation plan in response to the recommendations of the Independent Review, in which it committed to consulting on the current suite of Approved Documents and how to make them more user friendly. In June 2019 the Ministry of Housing, Communities and Local Government launched its consultation for a new building and fire safety programme entitled ‘Building a Safer Future: Proposals for reform of the building safety regulatory system’. On MMC the consultation document says:
A key issue for compliance will be confidence in quality assurance systems being used for fabrication offsite and installation onsite. Our proposal is that the construction products regulators should play a role in ensuring modern methods of construction meet the standards they are being marketed as meeting and work with other regulators to make sure they are installed and used in a safe way.
However, it does not indicate the guidance within the Approved Documents will be updated to take MMC into account.
98.Representatives from homebuilders, Barratt Developments and Taylor Wimpey said building regulations needed updating to facilitate compliance and to take into account MMC for building homes:
Steven Boyes: Building regulations need overhauling and need a specific section on MMC. Currently, you need to go through all the various parts of building regulations to get to those elements relative to MMC. If MMC is going to be a big driver of volumes, it needs to have its own section. I also feel that there needs to be more clarity with regard to fire safety in building regulations.
Jennie Daly: The current building regulations do not tend to focus on MMC. Approved Documents A and B focus on traditional and timber frame construction, and MMC is then left to interpretation to a degree, which is not particularly helpful with compliance. [ … ] We would be supportive of updating the building regulations to reflect the needs and different requirements of MMC.
99.Some witnesses also raised concerns about innovative methods of construction and fire safety in the context of the building regulations. The London Fire Brigade reiterated the findings of the Independent Review of Building Regulations and Fire Safety and said the current system does not ensure MMC buildings are safe:
However, the wider industry has forged ahead with increasingly innovative construction methods and materials at a time when it has been identified in the Independent Review of Building regulations and Fire Safety led by Dame Judith Hackitt that the system which is meant to ensure the safety of buildings is broken. In our experience this has sometimes resulted in a building being proposed using MMC materials where the potential fire performance has not been fully appreciated.
100.The Fire Sector Federation raised similar concerns:
This also raises the matter of effective control by regulators and again current concerns exists that UK building guidance and regulations are not sufficiently detailed to ensure safe use of MMC. Common use building materials like plastic can in certain circumstances create pathways for external fires to enter structures or fire barriers and seals may be rendered ineffective by surrounding materials. Guidance and understanding are essential in maintaining effective fire stopping.
101.The current suite of Approved Documents is confusing and difficult to comply with. It is particularly difficult for homebuilders that use MMC to apply the regulations to their developments. This could result in compromised safety standards in MMC buildings. The consultation on the building and fire safety system is welcome but does not consider specific guidance for MMC builders to help them comply with current regulations. The Government should urgently set out a clear plan for the review of the whole suite of Approved Documents, including a timeline for implementation. This review should consider how the Approved Documents relate to MMC buildings and where relevant, provide additional guidance on how MMC homebuilders might reach the required standards.
102.Estimates on the proportion of total UK carbon emissions produced by the built environment vary; The Royal Institute of British Architects quoted 30% for direct and indirect emissions, while the UK Green Building Council put the figure at 40%. It is clear that the built environment produces a significant proportion of the UK’s greenhouse gas emissions and therefore has a key role to play in making buildings more energy efficient and reducing their carbon footprint, in order to meet the Government’s target to eradicate the country’s net contribution to climate change by 2050. WRAP estimate that modular construction can reduce energy used in the construction process by 67% and waste produced onsite, by 70–90% in comparison with traditional construction methods. James Thomson from Keepmoat Homes told us that MMC homes: “take about 20–30% less to heat than a traditionally built new home”.
103.The building regulations set the standard for energy performance in new and existing buildings. The Chartered Institute of Housing warned that in future higher levels of energy efficiency might be required in order to reduce the impact of the built environment on climate change. In that case, inefficient homes built today would need retrofitting at a later date in order to comply with the more stringent energy performance requirements:
Just 1% of new homes built in 2018 met the highest Energy Performance Certificate standard (Band A). This represents a huge and irresponsible waste of an opportunity to upgrade the energy efficiency of the stock–especially as the least efficient of the homes built now will need expensive retrofit work within a few years if standards are suddenly raised, as the climate worsens. MMC provides the opportunity to tackle this problem by embedding high standards–but also carries the risk of it being extremely difficult to retrofit in later years if houses are built to inadequate standards now and by methods that make retrofitting expensive or technically difficult.
104.In its written evidence, homebuilder, Keepmoat Homes said its MMC homes are: “built using high performance materials which exceed current building regulations by over 20%”. In his oral evidence, James Thomson from Keepmoat Homes suggested that if regulations on sustainability was tightened it would push developers towards modular construction. The Minister of State for Housing said if MMC homes are more energy efficient we should encourage more of them:
Mary Robinson: If passive house standards are more achievable through MMC, should we be encouraging more MMC?
Kit Malthouse: Yes, absolutely. If we get better standards with MMC, we absolutely should. This is an imperative that we have, morally as well as practically, to do our bit for climate change
105.To meet its target to eradicate the UK’s net contribution to climate change by 2050, the Government should embrace every opportunity to reduce carbon emissions. It should be ambitious in setting carbon reduction targets for the built environment both during construction and in use. The building regulations should set more stringent energy performance targets for homes to take into account achievable levels of energy efficiency. MMC should be used to deliver more efficient homes now to avoid costly retrofitting of homes later to comply with more rigorous energy efficiency targets.
134 Ministry of Housing, Communities and Local Government, Collection: ‘’, April 2016
135 Independent Review of Building Regulations and Fire Safety: , December 2017, p16
136 Ministry of Housing, Communities and Local Government, ‘, p.102
139 London Fire Brigade
140 Fire Sector Federation ()
141 Royal Institute of British Architects ()
142 UK Green Building Council, , accessed 14 June 2019
143 Prime Minister’s Office, 10 Downing Street,’ ’, 12 June 2019
144 WRAP, , p7
145 WRAP, , January 2007, p 18
147 Chartered Institute of Housing ()
148 Keepmoat Homes 
Published: 3 July 2019