UK wants to promote domestic structural timber in the C16 class

 Wednesday, October 22, 2025

From a recent report, the UK government announced that the woodworking and construction industries are entering a new era of domestic sourcing, as stakeholders mount an ambitious campaign to increase the use of UK‑grown structural timber graded at strength class C16. Under the banner of initiatives such as Confor and Timber Development UK, sawmills, merchants and builders are collaborating to shift the balance away from imported materials and toward home‑grown supply.

In the UK market, softwood structural timber is commonly available in grades such as C16 and C24. C16 is often produced from faster‑grown, domestically harvested softwoods and is commonly used for stud walls, joists, floor framing and roof structures. Historically, however, specification habits have gravitated toward C24, which tends to originate from slower‑grown imports. One key industry insight: “Most coniferous structural timber used in the UK is either C16 or C24… specifying C24 softwood will tend to exclude most UK grown timber by default.”

Leveraging C16 effectively requires a recognition that for many applications the higher strength class of C24 is simply unnecessary — when C16 is suitable and plentiful. The current campaign aims to remedy both awareness and supply. As one initiative states, by choosing C16, tradespeople and homeowners can “support British forestry, protect jobs, and cut down on timber miles.”

Grow • Manufacture • Specify • Build

The strategy adopted by Confor, Timber Development UK and their partners places a clear four‑step structure at its heart:

• Grow: Increase and manage productive woodlands in the UK, thereby boosting the raw material base for future construction timber.
• Manufacture: Improve the capacity and capability of UK sawmills to process logs into strength‑graded C16 structural timber, adding value domestically.
• Specify: Engage builders, architects and specifiers to recognise that C16 meets many structural needs — and that using UK timber supports sustainability and local jobs.
• Build: Actual uptake on site — seeing domestic C16 used in framing, joists, stud walls and roof structures across the country.

One campaign, for example, was launched by BSW Timber to encourage greater use of British C16. “We want to change the way the construction industry thinks about strength‑graded timber,” the company explained.

For regional sawmills and timber merchants, the push offers an opportunity to boost domestic production and reduce dependency on imports. For end‑users — such as carpenters, builders and specifiers — the advantages include shorter supply chains, lower transport emissions and often cost‑effective availability of the correct grade for many structural uses.

From a sustainability perspective, the benefits are clear: home‑grown timber can contribute to carbon sequestration, local economic growth, and reduced “timber miles”. The campaign emphasises that choosing C16 British timber isn’t simply a substitute but a strategic move toward a more circular, sustainable material economy.

Moreover, promoting C16 addresses a long‑standing mismatch in the UK supply chain — where specifying a higher grade (C24) by default often meant relying on imported timber, even when C16 would have been entirely suitable. By shifting mindsets and specifications, the industry aims to rebalance supply and demand in favour of domestically sourced products.

Despite the positive momentum, some practical factors require attention. While C16 is suitable for many structural applications — studs, joists, floor and roof framing — it does have lower strength parameters than C24. Specifiers must evaluate loading, spans and usage correctly. Industry sources note that C16 often comes from faster‑grown trees and may show more defects (knots, etc) than higher grades — but it remains fit for purpose when correctly graded and used.

Merchants are already listing C16 timber widely: one UK timber merchant offers a full range of C16 joists and carcassing, noting that “C16 is normally the grade that is produced from faster‑grown UK timber”. Educating branch staff, builders and specifiers is a key element of the campaign. For example, one merchant is touring branches with interactive drop‑in training sessions to help change perception around C16.

Multiple factors converge to make this push timely:

• Increased emphasis on sustainable sourcing and local supply chains, driven by climate goals and resource resilience.
• Post‑Brexit and supply‑chain volatility making imports less attractive / more risky.
• A construction sector under pressure to build more, faster and with greater cost‑control. Domestic production of structural timber helps reduce lead times and transport cost.
• The need to support domestic forests and timber industries — the forestry and timber manufacturing sector is a significant contributor to the UK economy, supporting jobs and rural communities.

To realise the full potential of the campaign, several steps are critical:

1. Specification uptake: Architects, structural engineers and contractors must recognise when C16 is adequate and select it accordingly, reducing default to higher grades when unnecessary.
2. Supply chain alignment: Sawmills and merchants must ensure sufficient supply of domestic C16, including kiln‑drying, machining and grading to required standards.
3. Quality assurance & certification: Ensuring the C16 available is correctly graded, with appropriate moisture content, regularising and preservation as required for structural use.
4. Awareness and training: Educating all levels of the supply chain — from merchant staff to onsite builders — around correct use, design spans and benefits of domestic sourcing.
5. Marketing and procurement policies: Developers, public procurers and large contractors can champion British‑grown timber in their material policies and specifications.

The drive to promote domestically grown C16 structural timber in the UK represents a potentially significant shift for the woodworking and construction sectors. By encouraging the use of UK‑grown, strength‑graded timber, the industry can achieve greater sustainability, support local economies and build more resilient supply chains.

As the campaign gains traction, specifiers and builders have an opportunity now — to challenge default habits, make informed grade selections, and embrace a home‑grown material that is fit for many structural purposes. The collective approach of “Grow, Manufacture, Specify, Build” provides a clear blueprint for transforming how the UK sources and uses timber in construction. For those in the structural timber market, the message is clear: British C16 is ready for purpose — and the time to act is now.

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Tags: C16 timber campaign UK, domestic sawn timber UK, home grown forestry UK, timber in UK buildings, UK structural timber, UK timber supply chain