Britain Imports Most of Its Timber—Could Homegrown C16 Change the Specification?

A specification habit with national consequences

In April 2026, the Forestry Commission highlighted a striking gap in Britain’s timber economy. The United Kingdom consumed about 48 million cubic metres of wood and wood products in 2024, while approximately 75–80% of the timber it used was imported.

The Commission’s message to woodland owners and construction professionals is that domestic timber can enter higher-value markets, including structural construction. One practical barrier is specification. C24 strength-graded softwood is often treated as the default, even when the structural calculation does not require it. Most UK-grown softwood is more commonly graded C16.

The key point is not that C16 and C24 are interchangeable. They have different characteristic properties and must be used according to engineering design. The point is that C16 is suitable for many structural applications, and an automatic C24 specification can exclude domestic material before a supplier has the chance to compete.

What the strength class means

Structural softwood is graded into strength classes under standards including BS EN 338. The class provides characteristic values used by engineers, such as bending strength, stiffness and density. A higher number does not make a product universally “better”; it indicates a different set of design properties.

A member designed in C16 may need a larger section, closer spacing or a different arrangement than one designed in C24. In other cases, the same practical section may already have enough capacity in C16. Only calculation can establish that.

For timber-frame software, strength class should therefore be an explicit design input connected to real material libraries, structural checks and procurement data. It should not be buried as an assumed default. Changing grade can affect member sizes, quantities, cost, carbon data and the availability of local supply.

Specify domestic supply at the right moment

The Forestry Commission advises considering UK-grown timber at design stage. That timing is crucial. Once grids, spans and panel build-ups have been fixed around an imported grade, switching later may trigger redesign. Early coordination allows the engineer, architect, manufacturer and supplier to test what is locally available.

This does not mean writing a vague “British timber” preference without checking legality, certification, moisture content, grading and product consistency. Structural timber must be correctly graded and placed on the market with the required documentation. Responsible forest management and chain-of-custody information remain important.

It also does not mean every project can or should source every member domestically. Certain dimensions, species, engineered products or appearance grades may remain more readily available from overseas. A resilient strategy begins with accurate demand rather than a blanket claim.

From low-value logs to long-life buildings

The commercial opportunity is significant. When appropriate logs reach construction-grade markets, woodland management can capture more value than lower-grade uses. In turn, predictable construction demand can support investment in grading, drying and processing.

Domestic supply can also shorten some transport routes, but transport alone does not determine environmental performance. Forest management, yield, processing energy, material efficiency and service life all matter. The strongest case for homegrown C16 is practical: use a verified structural product where its properties meet the design, avoid unnecessary over-specification and build a more diverse supply chain.

A small setting with a large effect

For many designers, the change begins with a drop-down menu. If software defaults every softwood member to C24, that decision can propagate into calculations, schedules and purchase orders. Offering verified C16 options—and showing the dimensional consequences clearly—makes local procurement testable.

The 2026 Forestry Commission guidance turns a national dependency into a design question. Britain will continue to trade timber internationally, but it can also use more of the structural resource grown at home. The first step is to specify performance honestly, rather than asking for a grade the project may not need.

Sources

Forestry Commission, “Unlocking the value of your woodland: high-value markets for timber”, 29 April 2026: https://forestrycommission.blog.gov.uk/2026/04/29/unlocking-the-value-of-your-woodland-high-value-markets-for-timber/

UK Government, “Timber in construction roadmap 2025”: https://www.gov.uk/government/publications/timber-in-construction-roadmap-2025