How and where to use guide
3.6Mtr X 47 X 125mm (5" x 2") C24 Treated Regularised KD Carcassing Timber
Floor joists and suspended floors
This timber is commonly used for floor joists in domestic and light commercial construction. The C24 grade provides adequate load-bearing capacity for residential floor loads when installed at appropriate centres. Span capability depends on joist spacing and load class—consult structural design tables or a structural engineer for your specific span and loading conditions. Ensure adequate bearing at each end (typically 75–100mm minimum) and install with the wider face vertical for maximum strength.
- Install with 125mm dimension vertical for maximum bending strength
- Provide minimum 75–100mm bearing at supports
- Space joists according to design requirements and load class
- Check span tables for your specific joist spacing and loading
Stud walls and partitions
Suitable for timber-frame stud walls in both load-bearing and non-load-bearing applications. The regularised finish aids plumb installation and reduces on-site planing. Install studs vertically with the 47mm dimension facing the direction of lateral load. Brace adequately during construction and ensure proper connection to head and sole plates. For load-bearing walls, confirm stud spacing and grade meet building regulations and structural requirements.
- Install studs vertically with 47mm dimension facing lateral loads
- Space studs according to design and building regulations
- Provide temporary bracing during construction
- Ensure secure fixing to head and sole plates
Roof battens and framing
The 47 × 125mm section is suitable for roof battens, rafter ties, and secondary framing in roof construction. Confirm spacing and sizing against your roof design and local building regulations. The pressure treatment provides protection in roof voids where ventilation may be limited. Ensure adequate ventilation in roof spaces to manage moisture and prevent condensation.
- Size and space battens according to roof design and regulations
- Ensure adequate roof void ventilation
- Use corrosion-resistant fixings to rafters and trusses
- Check for moisture and condensation risk in enclosed spaces
Decking frames and outdoor structures
The pressure treatment makes this timber suitable for decking subframes and outdoor structural applications. The 47 × 125mm section provides good strength-to-weight ratio for deck joists. Ensure adequate drainage beneath decking to prevent water pooling. Use stainless steel or hot-dipped galvanised fixings to prevent corrosion. Allow for seasonal movement and moisture changes in outdoor applications.
- Provide adequate drainage and ventilation beneath decking
- Use stainless steel or galvanised fixings throughout
- Allow for seasonal timber movement in design
- Inspect regularly for signs of moisture or decay
Building regulations and structural design
This timber meets BS EN standards for structural softwood. However, final suitability depends on your specific application, span, loading, and local building regulations. For load-bearing applications, consult span tables or engage a structural engineer to confirm the grade and sizing are appropriate. Non-load-bearing applications (such as non-structural partitions) have less stringent requirements but should still follow good building practice.
- Confirm compliance with local building regulations
- Use span tables or structural engineer for load-bearing work
- Check moisture conditions in service—avoid prolonged dampness
- Inspect timber before installation for damage or defects