10x2 Timber Treated C24

Understanding 10x2 Treated Timber

47mm x 250mm sawn treated timber, traditionally known by the nominal 10x2 inch trade size, represents one of the deepest and strongest standard carcassing sections available for UK construction. These sections are kiln-dried to achieve high dimensional stability and are strength-graded to C24 specifications. This premium grading ensures a dense grain and minimal defects, providing the mechanical properties necessary for safety-critical applications where high tensile strength and minimal deflection are non-negotiable.

To guarantee a long service life, the timber undergoes a rigorous high-pressure preservative treatment. This process ensures deep penetration of biocides into the wood fibers, protecting the structural core from fungal rot, dampness, and wood-boring insect attacks. This is particularly vital for deep joists used in ground-floor applications or flat roofs where ventilation may be restricted.

The timber is regularised to a finished size of approximately 45mm x 245mm. The planed finish and eased edges ensure uniform depth across all lengths, allowing for the precise installation of floor decks and ceiling finishes. With its significant 250mm profile, this timber allows architects and engineers to specify longer clear spans, reducing the need for supporting walls or steel beams.

Material Range

• Individual 47mm x 250mm Lengths: Structural pressure-treated lengths available in 3.6m, 4.8m, and 6m sizes to accommodate substantial structural spans.
• Bulk 10x2 Timber Packs: Trade-scale 44-length packs designed for high-volume efficiency on site, providing a consistent supply for major flooring and roofing projects (available for 3.6m and 4.8m lengths).
  
  

Performance Benefits

• Maximum Load Capacity: Graded to sustain significant dead and imposed loads across wider spans than smaller timber sections.
• Biological Protection: Pressure-treated with advanced preservatives to prevent fungal decay and insect infestation in internal and external environments.
• Enhanced Stability: The kiln-drying process removes excess moisture, ensuring the timber remains straight and resists warping or twisting after installation.
• Precision Regularisation: Planed on all four sides with eased edges to ensure uniform dimensions and improved site ergonomics.
  
  

Typical Applications

• Long-Span Floor Joists: Supporting internal floors in large residential buildings and commercial units.
• Flat Roof Frameworks: Providing the necessary depth for heavy roof loads, insulation, and fall creation.
• Heavy-Duty Timber Framing: Constructing the primary load-bearing skeleton for large-scale timber-frame buildings.
• Decking Substructures: Forming a rigid, rot-resistant foundation for high-specification external platforms and walkways.
• Mezzanine Flooring: Creating high-strength secondary floor levels in warehouses or industrial settings.
  
  

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 599-1: Efficacy of preventive wood preservatives as determined by biological tests.
  
  

Related Materials and Construction Uses

These 47mm x 250mm sections are the preferred choice for structural engineers requiring premium structural wood with high density and strength. In demanding builds, these deep profiles are frequently used in conjunction with other structural timber for joists to create complete, code-compliant flooring and roofing assemblies.

Due to the weight and structural importance of these sections, they must be installed with appropriately rated heavy-duty galvanised hangers and bridging to prevent lateral movement. To maintain the integrity of the pressure treatment, any on-site cuts, notches, or drill holes must be thoroughly treated with a proprietary end-grain preservative.