How and where to use guide
3.6Mtr X 47 X 150mm C24 Treated Regularised KD Carcassing Timber
Structural applications
C24 timber is strength-graded to C24 standards, making it suitable for load-bearing structural work. It offers enhanced stability and improved strength compared to lower grades such as C16, with fewer knots and more consistent properties.
- Floor joists in domestic and light commercial buildings
- Roof battens and rafter support
- Stud walls for internal partitions and external framing
- Decking frames and outdoor structures
- General construction and framing work
Indoor applications
Within buildings, C24 timber performs well in dry, protected environments. The treatment provides additional protection against fungal decay, making it suitable for areas with occasional moisture exposure.
- Floor joists in kitchens and bathrooms where moisture levels are moderate
- Stud walls in all room types
- Roof structures and attic framing
- Internal structural supports and lintels
Outdoor and exposed applications
The pressure-applied preservative treatment protects this timber against rot, fungal decay, and insect attack, making it suitable for outdoor use. However, exposure to weather will gradually weather the timber surface.
- Decking frames and structural supports for garden structures
- Outdoor pergolas and shade structures
- Fence posts and structural framing (where ground contact is avoided)
- Shed and outbuilding frames
- Exposed roof structures in covered areas
Limitations and considerations
Whilst treated carcassing timber is durable, certain applications require additional protection or alternative materials.
- Avoid direct ground contact; use concrete foundations or treated posts for ground-level structures
- Not suitable for permanent immersion in water; use marine-grade timber for wet environments
- In high-moisture areas (such as wet rooms), ensure adequate ventilation and consider additional protective measures
- Check local building regulations and structural engineer requirements for your specific application
Compliance and standards
This timber meets current BS EN standards for strength-graded softwood carcassing, ensuring it is suitable for structural applications across the UK.
- Strength-graded to C24 in accordance with BS EN 338
- Pressure-treated in accordance with BS EN 351-1
- Regularised finish provides consistent sizing for professional installation