Adopting Modern Methods of Construction can cut both embodied carbon and carbon emissions from deliveries to the construction site. Manufacturing in a controlled environment reduces waste, and it can enable the use of lower-carbon materials such as timber in place of concrete and steel. We’ve calculated that using volumetric modular construction (MMC Category 1) – can cut the number of deliveries required for a typical city centre residential apartment floor plate by over 85%: from about 100 deliveries to around 12. 

Our design for a housing developer reverted their everyday reinforced concrete frame solution for their apartment buildings to a steel chassis volumetric modular systems. This platform approach reduced the volume of waste material, improved quality control and reduced deliveries to site, meaning a further reduction in vehicle movements and congestion.

MMC can be used to cut carbon in both low-rise and high-rise developments. On a high-end residential 54-storey apartment we proposed a hybrid approach. This utilised the use of thin in-situ post-tensioned (PT) concrete slabs supported off precast vertical elements; columns and core walls. The precast elements were manufactured offsite and brought to site ready to lift into place, which eased the programme and improved the floor cycle times. The carbon saving from this process is enabling the project to meet LETI 2030 embodied carbon standards, whereas an in-situ concrete frame constructed with PT slabs supported on traditional reinforced concrete vertical elements used on a similar neighbouring building (constructed in 2015) only meets the requirements for LETI 2020.

Thousands of elements were constructed off-site, including 774 precast panels that form the envelope of more than half the hospital. Manufacturing these panels, which combine façade elements with structural backing, off site, and fitting windows at the same time meant there was no need for scaffolding on the site. 

Slabs were designed with a 75mm rebar biscuit on the bottom so they could be dropped by crane straight onto trestles, and workers could then walk on them safely to install rebar. The precast biscuit also came with edge trims and handrail sockets so these could be installed easily to keep people safe.

Bringing these and other complete manufactured elements, such as bathroom pods, to site instead of individual materials also reduced vehicle movements by 30%, reducing disruption and emissions. 

Is MMC right for your project?

As well as cutting carbon and construction programmes, MMC also provides greater certainty over costs, making it easier to get project finance, and brings with it safety benefits. At Grange University Hospital MMC saved 237,099 hours of on-site labour, reducing the health and safety risks associated with working on site. 

It’s not just for new build projects. With MMC, older buildings can be adaptively reused instead of being demolished and replaced. We’ve designed a four-storey extension using a steel-timber hybrid frame on top of an existing traditional concrete structure to give new life and use for the building. Using MMC in this way means that the existing foundations won’t have to be strengthened, cutting both carbon emissions and the programme time. 

It's hard to think of any building that wouldn’t gain from employing at least one element of modern methods of construction. Yes, MMC does require a change of mindset, but the time to make that change is now. We encourage our clients to talk to their advisers about MMC early in a project; if you engage early, it’s not as difficult as you might think.