Oct 25, 2019
MMC and timber frame: the perfect duo for low-carbon sustainable housebuilding
Stewart Dalgarno, Director of Product Development at Stewart Milne Timber Systems, discusses why modern methods of construction coupled with a build fabric such as timber frame is key to meeting government housing targets sustainably.
Industry reports are increasingly signalling a move towards modern methods of construction (MMC) in the housebuilding sector. A phrase coined by the UK government, it acts as a definition and framework to encourage developers to adopt and champion construction practices which will speed up delivery, plug the skills gap, and, crucially, drive for a low carbon sustainable economy.
In the housebuilding sector, MMC can have a transformational impact. With the UK currently experiencing a housing shortage and government statistics stating a further 120,000 homes are needed annually, modern methods of construction, and in particular, offsite timber building solutions, are vital in addressing the shortfall.
But as demand for increased production is driven by the industry, it is absolutely crucial that low carbon sustainability remains front-of-mind throughout. This is where the build fabric itself becomes just as important as the construction method.
Taking a ‘fabric-first’ approach and using offsite timber frame construction is a proven means of ensuring sustainability and low-carbon compliance is part of the very heart of the development, in the materials used, construction stages and for the remainder of its lifecycle.
A natural, renewable low-carbon material, timber is readily available, economically viable, versatile and is a carbon-neutral building material in itself – for every tree used in a timber frame home, more are planted. This is converse to concrete blocks and mortar, which is an energy-intensive and non-renewable method of construction.
Offsite timber frame construction provides the building with a superior thermal envelope, requiring minimal maintenance and a fit-and-forget solution for the lifetime of the building. For a home to be as energy efficient as it can be, it must be as insulated and air tight as possible, and with timber construction retaining and reducing heat demand, the resulting building becomes extremely fuel efficient.
Offsite timber frame construction is a proven mainstream construction solution, with a track record in superior energy efficiency and low embodied carbon. It is reliable, cost-effective and the dominant method of construction in many countries, in addition to being the first choice for self-builders, where energy efficiency, low-carbon construction, and cost are key specifications.
Recently, the government announced the introduction of the Future Homes Standard by 2025, marking a true declaration of intent from the UK government to ensure environmental sustainability carbon reduction and climate change are key considerations in industry.
In housebuilding, we’re already seeing a move towards low-carbon homes, both in the production and how people use them. The latest announcement reinforces the commitment from the UK government and further builds on the original ‘code for sustainable homes’ method for assessing new builds in 2006.
The Future Homes Standard ensures new build homes are future-proofed with low-carbon heat and power and world-leading levels of energy efficiency – tying in with the Chancellor’s pledge to reduce fossil fuel use in homes by 2025.
It’s undeniable this approach is necessary and in-line with wider global policy on sustainability and climate change. The Future Homes Standard will play a key role in the sustainability and climate change puzzle, and while many housebuilders are already working towards low-carbon homes, more can be done.
The latest statement from the Chancellor will drive changes in UK building regulations to be applied to all new builds – from housing to commercial builds – all working towards a more sustainable, energy efficient, environmentally-friendly and efficient building regime and in this, timber frame plays a key role.
The industry is already well-equipped to scale-up in its adoption of timber as a build fabric combined with modern methods of construction. The UK offsite timber frame infrastructure in the form of supply-chain, materials, skills and capacity already exists to meet current and future housing targets and modern timber techniques have been used in thousands of new home builds, for decades.
In Scotland, for example, 80 per cent of new homes and apartments are constructed offsite using timber frame. Scotland is leading the way in the UK on this front and has continued to drive fabric energy efficiency well beyond regulations in England and Wales.
A sustainability standard has been in place for some years now in Scotland, which is reflected in the positive strides the country is making towards a carbon-neutral sustainable economy. The average energy demand of new build Scottish homes is already climate resilient in comparison to current homes in England.
While it’s not yet zero-carbon, it’s as close as we can realistically look with the current technology and resource available, but Scotland remains a global leader in energy efficiency within the housing sector and will continue to develop solutions to achieve zero carbon housing.
The advantages of using offsite timber frame are three-fold: low energy demand, carbon-neutral raw material, and a proven, reliable, cost effective mainstream way of building high quality energy efficient homes. It’s therefore clear that in the multi-faceted approach which must be taken to create sustainable climate resilient homes for the future, that timber, and a fabric-first approach, will play a central role in enabling those other facets, such as renewable energy and smart technologies, to work as efficiently and harmoniously as possible.
While sustainability remains a priority, there are numerous other well-known benefits of the timber and offsite construction duo. For housebuilders, there’s no denying a de-risked, more predictable and accelerated speed of build will be essential for the sector to increase the number of new homes delivered, with confidence.
Modern methods of construction can tackle this specific challenge, including the ability to quickly produce large volumes of build systems to exacting standards. Timber offsite construction can produce high volumes of high-quality, high-performance timber frames ready to be transported on-site, where a typical four-bedroom detached home can be erected, wind and watertight in as little as five days. Using offsite construction and timber, it’s possible to complete a project of ten blocks of terraced houses five weeks earlier and more reliably than if building with masonry or other traditional on-site methods.
This method of construction ensures robust quality and guaranteed performance standards are met consistently. It facilitates early collaboration engagement and a partnership approach as the design, engineering and technical teams work with housebuilders and contractors from the initial design concept and development through to manufacture, delivery and construction – crucial to ensuring high quality output and realising cost benefits, through early resolution of issues and ongoing value engineering.
In any intensive, large-scale build programme there are cost pressures, but offsite construction can significantly reduce both labour and material costs on a par with conventional methods. There is less reliance on trade skills and on-site supervision, and the faster, more predictable build of the main structures reduces the management required to supervise and co-ordinate on-site trades. The accelerated build time provides a quicker return on capital outlay, and on-site preliminary expenditure can be reduced.
Offsite timber frame construction provides housebuilders with many of the answers, but it’s also collaboration within the industry that will be crucial in bridging the housing gap. Industrialisation through offsite construction, digital working and lean site assembly, can deliver high-quality homes costing the same or less than houses which have been built traditionally.
Taking a timber frame, fabric-first approach to homes is the most effective means of meeting major housebuilding and net-zero carbon targets sustainably. It’s affordable, proven, and requires no maintenance in the long-term. A true fit and forget approach, which is cost-efficient year on year for the lifetime of the development. It positively impacts the social agenda as more efficient homes reduces energy bills for tenants, thereby decreasing fuel poverty.
For many, building low-carbon homes is already high on the agenda and has been for some time. However, measures such as the Future Homes Standard will simply underpin and provide additional momentum to drive the uptake of offsite timber frame construction as the go-to solution of choice across the UK.