Andrew Orriss of the Structural Timber Association (STA) urges housebuilders to continue to invest in timber frames, exploring how the method can meet sustainability demands as well as those of efficiency and productivity.
The UK housebuilding industry has faced numerous challenges in recent years – ranging from Brexit to a global pandemic – not to mention the economic challenges we are all facing today. Regardless, the structural timber industry has continued to grow and with the advantages timber brings to the construction table – from its environmental credentials and design flexibility to reducing site time, vehicle movements, and relieving skill shortages – the increasing appetite for timber frame isn’t letting up.
With productivity a 2023 watchword, the use of timber frames and Structural Insulated Panels (SIPs) construction is a way to move the industry forward.
LIGHTWEIGHT TIMBER SYSTEMS – THE DIFFERENCES & PRODUCTIVITY BENEFITS
Timber frame and SIPs are lightweight timber systems that are favoured for low and medium-rise buildings. The popularity of these systems in Scandinavia and even as close as Scotland, where
85% of homes are timber-framed, showcases the full adoption of timber as a renewable construction material. In comparison, timber comprises only around 10% of the market share in England. However, the UK market share for timber is slowly increasing, which is a positive development.
Offsite timber frame construction offers faster build times and higher sustainability standards compared with traditional construction methods. There are two types of timber frame systems – open and closed panel systems. The main difference between these systems lies in the amount of factory value added to the closed panel timber frame.
Open panel systems are panels that are structurally engineered to serve as the load-bearing inner leaf of the external wall. They consist of studs, rails, and sheathing on one face, with a breather membrane. On the other hand, closed panel systems are pre-insulated, and some come with fitted windows and internal service zone battens for easy installation and construction.
The other popular lightweight timber system in the market is SIPs, which can be used for walls and roofs. This advanced method of construction uses composite panel techniques whereby an insulating foam core is sandwiched between two structural facings, normally Oriented Strand Board (OSB).
SIPs, like timber frame systems, are produced in factory settings and can fit any building design. They provide a lightweight build system that is extremely robust, energy-efficient, and quick to erect. This offers a greater opportunity to meet emissions targets while also achieving quick construction and completion.
DESIGNING FOR NET ZERO BRINGS ESG & COMMERCIAL BENEFITS
The recognition of the versatility and sustainability benefits of timber is now widespread. Timber offers the construction industry an opportunity to significantly reduce its carbon footprint through zero carbon design and low embodied carbon. The demand for environmental, social, and governance (ESG) principles in construction projects driven by clients is on the rise, as illustrated by market research conducted by PwC.
Furthermore, timber offers specifiers a genuinely renewable alternative to traditional construction materials. Typically, for every tree cut down in a well-managed and maintained farmed forest, another five are planted.
In terms of energy consumption of buildings in use too, energy-saving technologies make it easier to super insulate a timber frame or SIPs home, which will significantly reduce the energy required to heat the home. Achieving the same fabric efficiency in a traditional masonry build would be much harder, taking more space as well as costing more time and money. This is a positive development for both the environment and the homeowners’ budgets, making a home cheaper to heat and cutting its emissions over its lifetime.
Apart from substantially reducing carbon emissions, the use of timber in construction offers other benefits. When considering Pre-Manufactured Value (PMV), a timber frame building can represent between 30% and 55% of the building fabricated offsite. So, for those housebuilders looking to develop their social housing share as a result of the Government’s £11.5bn Affordable
Homes Programme 2021-26 (AHP), under which 25% of funded projects must be delivered using MMC, there’s real commercial potential.
MAINTAINING PROGRESS & COMPLIANCE
As the economic downturn begins to impact everyone across the construction industry, we certainly encourage construction companies to not revert back to traditional methods of construction, and instead consider the whole life costs of the building.
We need to continue the progress made with the use of timber in construction, but it must not happen at the expense of standards and build quality. The Structural Timber Association’s Quality Assurance Scheme – STA Assure, offers firm reassurances that STA members are supplying products and systems to an audited quality scheme, meeting or even exceeding current legislation and regulatory requirements. The scheme ensures that members keep on top of the constantly increasing industry expectations on quality and competency, and as legislation continues to evolve, the technical support offered by the STA is invaluable. The importance of these schemes cannot be overstated and offers all stakeholders confidence in the quality of the homes built.
In what is a challenging 2023, and looking forward, it will be essential for industry stakeholders to collaborate to achieve growth. By prioritising compliance, early engagement and collaborative working, there is plenty of cause for optimism for the year ahead.
Andrew Orriss is the chief operating officer of the Structural Timber Association (STA)