9x2 Timber Treated C24

Understanding 9x2 Treated Timber

47mm x 225mm sawn treated timber, frequently identified by its nominal 9x2 inch trade name, is a foundational component for large-scale structural framing. These sections are kiln-dried to improve dimensional stability and are strength-graded to C24 specifications, ensuring they meet the stringent mechanical performance standards required for safety-critical applications. The significant 225mm depth of this timber provides exceptional resistance to deflection, allowing for the creation of wide, open-plan spaces without the need for frequent intermediate supports.

To ensure long-term durability, the timber undergoes a high-pressure treatment process. This forces preservative biocides deep into the timber’s cellular structure, providing essential protection against wood-boring insects and fungal rot. This makes the material particularly suitable for "first-fix" applications - the critical structural phase of a build where components are often exposed to the elements before the building envelope is fully sealed.

The timber is regularised to a finished size of approximately 45mm x 220mm. This precision machining ensures a uniform profile across all lengths, which is vital for achieving a perfectly level floor or roof plane. With eased edges for safer manual handling, these lengths represent a reliable, professional-grade solution for the most demanding structural requirements.

Material Range

• Individual 47mm x 225mm Lengths: Structural pressure-treated lengths available in six sizes from 3m to 7.2m, ideal for bespoke structural framing and extensions.
• Bulk 9x2 Timber Packs: Trade-scale 55-length packs designed for volume efficiency on large sites (available for lengths between 3.6m and 6m).
  
  

Performance Benefits

• Maximum Structural Integrity: Graded to a high standard to support heavy dead loads and provide the stiffness necessary for long-span flooring.
• Preservative Excellence: Pressure-treated with Tanalith E to inhibit fungal decay and insect attack, significantly extending the service life of the framework.
• Superior Stability: The kiln-drying process removes excess moisture, ensuring the timber resists warping, twisting, or shrinking once installed.
• Consistent Regularisation: Planed-all-round to ensure uniform dimensions, allowing for faster and more accurate on-site assembly.
  
  

Typical Applications

• Long-Span Floor Joists: Supporting internal flooring in large residential rooms and commercial units.
• Main Roof Rafters: Forming the primary sloping support for heavy tiled or slated roof structures.
• Flat Roof Framework: Providing the deep structural base required for warm or cold flat roof designs.
• Structural Mezzanines: Creating high-strength secondary floor levels in industrial or retail environments.
  Heavy-Duty Decking Subframes: Constructing the foundational support for large-scale external timber platforms.
  
  

Specification & Standards

• BS EN 14081-1: Strength graded structural timber with rectangular cross section.
• BS EN 335: Durability of wood and wood-based products - Use classes.
• BS EN 350: Durability and classification of the durability of wood to biological agents.
  
  

Related Materials and Construction Uses

These 47mm x 225mm sections are often the primary structural choice for engineers requiring premium structural wood with high tensile strength. In domestic and commercial builds, these deep sections are frequently integrated with other high-performance joist timber solutions to create a rigid and reliable building skeleton.

Due to the structural importance of these sections, they should be installed with appropriate heavy-duty galvanised hangers and lateral bridging. To maintain the integrity of the pressure treatment, any on-site cuts or notches must be thoroughly treated with a suitable end-grain preservative to prevent moisture ingress and premature decay.