The drive to build more sustainable homes means the industry must reduce embodied carbon and construction waste. Brian Adams, Senior Director of Sales and Business Development, at Arclin examines whether the answer lies in timber frame housing and new innovations such as integrated weather resistant barriers.
Globally, the construction industry is the biggest consumer of raw materials and accounts for 37% of the world’s greenhouse gasses. With net zero now just a mere 25 years away, the UK has focused on reducing operational carbon emissions, with some considerable success thanks to legislation such as Part L. Further improvements in building energy efficiency are expected when the Future Homes Standard comes into force later this year.
While this will certainly help to meet the country’s latest interim target in the form of an 81% reduction in emissions by 2035, it won’t be enough. This means it’s imperative the construction industry reduces embodied carbon too.
Embodied carbon is all the emissions that come from construction materials and components. It includes carbon generated through the extraction, production, processing and transportation of construction products.
This means material choice will become a more important factor in building sustainability, because certain materials contain significantly less embodied carbon than others. Timber is a prime example.
Build with timber for lower embodied carbon
Timber from sustainable sources is an extremely environmentally friendly material. Trees sequester carbon dioxide through photosynthesis. This removes it from the atmosphere and stores it, so can help offset the energy needed for processing and transportation. This means timber has much lower levels of embodied carbon than materials such as bricks and mortar. As a result, properties built using timber can contain up to 60% less embodied carbon than those built from traditional materials.
For housebuilders, timber has the added benefit that it is light, strong, forgiving and flexible. This means it’s much easier to handle than concrete and steel. It’s ideally suited for offsite manufacturing and is already widely used in offsite assemblies such as SIP panels, which helps to speed up the construction process.
Despite its obvious sustainability and construction process benefits, so far, only Scotland has truly embraced it as a material for building homes. However, that’s set to change. The government recognises that increasing the use of timber in housebuilding is essential if the UK’s 4.3 million housing shortfall is to be addressed. As a result, it published the timber in construction roadmap, which aims to increase the supply of domestic timber production and boost levels of timber construction.
It’s worth noting that sustainability doesn’t just refer to construction methods. How a product or material is disposed of must also be considered when calculating embodied carbon.
Cutting back on plastic waste
The construction industry has a particular problem when it comes to waste. It is responsible for nearly two-thirds of the UK’s waste including 23% of plastic waste – a mountainous 1.15 million tonnes.
While plastic can usually be downcycled (turned into a material of lesser value), it still requires energy to do this, increasing the embodied energy of the end-product. Although, this cannot continue indefinitely – at some point plastic must go to landfill.
Historically this has been an issue for timber frame construction, because housewrap, a loose plastic-based product, is commonly employed to provide weather resistance, air tightness and vapour permeability. Housewrap can be applied both in the factory and/or onsite with careful detailing around doors and windows required. Excess material must be removed generating plastic waste.
There is however an alternative, in the form of new integrated weather resistant barriers, such as Arclin’s Arctek® Dryshell™. The overlay is applied directly to OSB sheathing boards in the factory, ensuring consistent, uniform coverage with no waste on site.
Timber frame walls, SIP systems, or cassettes arrive on site with a highly durable, airtight, windtight and watertight layer already in place – no cutting required. This means a weather-tight shell can be delivered more quickly, overcoming the risk of moisture penetrating timber panels during construction.
The added benefit is that manufacturing takes place offsite, reduces on-site operations, time and labour, and also increases the potential for carbon savings. In addition, a report by the BRE-managed BeAware project states that “it’s easier to manage waste in a factory environment than on a construction site.”
It’s true that there’s no single path to sustainable development. That said, timber frame construction and innovations like weather-resistant barriers present a compelling solution to the challenges of reducing embodied carbon and plastic waste in housebuilding. Embracing this could not only increase new home sustainability but also enhance efficiency, quality and speed of construction which in turn will help reduce the UK’s housing shortfall.
To find out more information on how performance overlay technology can support your timber frame building project contact Arclin here.