The term ‘Modern Methods of Construction’ (MMC) is often mentioned when discussions occur about the need to build more new homes. Richard Lankshear, the Innovation Manager at the NHBC, recently spoke with us about this approach to building homes.
Q. What do you classify or define as Modern Methods of Construction (MMC)?
“At NHBC we have a specific way of assessing MMC systems so we can understand the detail of the system and support our customers by carrying out a thorough review. As such we identify MMC as offsite manufacture, innovative technologies and other non-conventional methods of construction that form the structure and envelope of the home. This includes sub-assemblies, volumetric and panelised systems manufactured off site as well as site-based MMC.
“Not all offsite manufacture is necessarily a Modern Method of Construction as many conventional forms of construction are assembled offsite. We do not treat a system as MMC if the construction is described in the NHBC Standards and where the system components can be inspected on site.”
Q. What are the overall levels of new homes being built using these methods at the moment?
“We know that vast majority of homes are built with traditional cavity masonry – 74% in 2017 with 16% in timber frame and 1.5% in light steel frame with the balance in framed structures or unique systems. The picture differs in Scotland with 85% of houses built in timber frame. Looking at the trends, though, there isn’t a notable change in construction types and, if anything, there is a slight increase in the use of traditional cavity masonry construction.
“However, what we are seeing is an overall much greater interest in MMC systems. In the past we received between four and eight innovative systems to review each year, but this changed dramatically from about 2015/16 with over 30 systems received in 2016 and a further 25 the following year.
“We are expecting a record number of systems to review this year, with 20 submitted already over the first six months.”
Q. The sector continues to build fewer homes each year than the Government believes is necessary. Can the use of new building methods help to bridge this gap?
“It is perhaps too early to tell, but certainly we are seeing an increase in interest across the industry. The Government’s White Paper and the MHCLG report “Modernise or Die” set out the opportunities for greater use of MMC, and industry is certainly responding.”
Q. What do you see as the key reasons why a housebuilder should consider using MMC?
“The one reason that interests NHBC the most is the promise of improved quality. Our raison d’être is to protect homeowners and raise the standards of new homes and correctly designed, manufactured and installed MMC systems can help this aim.”
Q. Many housebuilders use traditional techniques and materials to build new homes as it is a building method with which they are familiar. Are you calling on housebuilders to switch to a form of MMC to replace these proven and understood methods?
“We expect homes built to the same high standards, whatever the construction type, and if the builder chooses an MMC system, we expect it to meet our technical requirements. To support this, NHBC carry out a review of MMC systems against key performance criteria based on the principle that all homes should;
- meet homeowners’ reasonable expectations
- be mortgageable
- be insurable
- have a design life of at least 60 years for the structure.
“As such, the more systems that we have accepted, the greater the choice for the builder in the construction of their site.”
Q. Do you have any tips for housebuilders who are considering using a MMC for the first time?
“There are great opportunities in the use of MMC and we see many house builders investing in new technologies. Those that are new to working with MMC and especially off-site manufacture should appreciate the difference in the procurement process.
“An early design freeze is critical in off-site manufacture, which may not be suitable for all projects or clients construction types or house builder’s business model. The detail design required to achieve a design freeze is sometimes underestimated by those starting out in the development of MMC, particularly in the need to consider the how the system integrates in the rest of the building. We would always encourage investment in the detail design of MMC and NHBC are happy to review and comment on new systems during design development.”
