Facing a growing demand for housing, many believe that building with timber could be a sustainable answer to meet residential construction goals.
In part because of the government’s commitment to promote timber use as part of the UK’s Net Zero Strategy, as well as initiatives to expand the domestic supply chain, housebuilders are under pressure to build with UK grown timber . But is this really a feasible solution?
Where do we get our timber from?
The UK imports around 80% of its wood, making it the world's second largest importer of wood after China.
From a sustainability perspective, the carbon cost of the timber demand for construction adds up. 49% of the total carbon footprint of UK timber is from transport, equalling 2,548,999 tonnes of CO2 emissions annually . The majority of these emissions (74%) come from road and maritime transport of imported timber products.
The reason the UK imports so much timber is due to both quality and quantity. In a report evaluating forestation in regards to the UK timber sector, the Confederation of Forest Industries told the House of Commons Environmental Audit Committee that: "the land area required to be planted with trees to supply all of the UK's timber needs from domestically produced timber could undermine food production".
The type of timber required for UK construction is also an issue. Whilst a mix of softwood, hardwood, and engineered wood is used in construction, softwood makes up around 80% of timber used around the world .
Structural softwoods in the UK are typically graded to C16 (standard strength) or C24 (higher strength) under British Standards (BS EN 338). In buildings, standard grade softwood (C16) is primarily used in applications such as floor joists, roof rafters, and wall framing. Higher strength grade softwood timber (C24) is used in situations where greater loadbearing capacity or longer spans are required.
There are over 30 species of tree native to the UK, only three of which are softwood, also known as conifers. British forests have been depleted in past centuries, and while in recent decades there has been an effort to regrow woodlands, the focus has been on native broadleaf hardwood species , which takes much longer to reach a stage where it can be used to build with.
Additionally, softwood trees tend to grow better in cooler, more northern climates. Non-native conifers that are planted in the UK grow faster than they would in their natural environments, which results in lower wood density . This can reduce its suitability for certain uses.
While there is a place for timber in construction, the issues with increasing the call for UK wood lead us to question if we should be looking at other locally sourced materials to help meet housing demands.
Are there building materials sourced in the UK?
There are many building materials that are commonly sourced in the UK, such as stone and various types of brick, but they cannot all be used in place of timber.
One material that offers an alternative to building with timber is aircrete. Aircrete is a lightweight masonry material, combining the strength, durability and thermal efficiency of concrete with the ease of use that comes with a lighter material, easy to cut and work with on site.
H+H UK produces a variety of aircrete blocks for internal and external walls using the ingredients: pulverised fuel ash (PFA), sand, cement, aluminium powder, lime and water, and ensures that 99% of all raw materials are sourced from UK suppliers.
Our Celcon Blocks are manufactured in the UK, with factories strategically based in the north and south. This enables us to efficiently supply housebuilders and builders’ merchants around the country without the higher carbon emissions associated with transporting loads for long distances.
Pinning the UK’s house building hopes on any one material as the only solution to meet demand will bring a plethora of issues. We believe that rather than focusing exclusively on timber when looking to the future, we need to look at the wider picture and explore the benefits of materials sourced and manufactured closer to home.
Sources
Policy paper. Timber in construction roadmap. 2023
Timber Development UK. The timber industry Net Zero Roadmap. 2022
United Nations. Forest Products Annual Market Review. 2007-2008
House of Commons Environmental Audit Committee, Seeing the wood for the trees: the contribution of the forestry and timber sectors to biodiversity and net zero goals, Fifth Report of Session 2022–23, 2023.
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