How and where to use guide
3.0Mtr X 47 X 225mm C24 Treated Regularised KD Carcassing Timber
Indoor structural applications
In indoor construction, C24 timber is ideal for floor joists, roof structures, and stud walls. The regularised finish provides a clean appearance suitable for visible applications, whilst the strength grade ensures adequate load-bearing capacity for residential and light commercial buildings.
- Floor joists in domestic and commercial buildings
- Roof trusses and rafter support
- Internal stud walls and partition framing
- Loft boarding and storage structures
Outdoor and exposed applications
The pressure-applied preservative treatment protects against rot and insect attack in outdoor environments. C24 timber is suitable for decking frames, garden structures, and external carcassing where durability and weather resistance are essential. Ensure adequate ventilation and drainage to maximise the life of the timber.
- Decking frames and substructures
- Garden structures and pergolas
- External carcassing and framing
- Fence and gate posts (where not in ground contact)
Design and load considerations
C24 timber offers enhanced strength and stability compared to lower grades, making it suitable for longer spans and higher loads. However, all structural applications must comply with current building regulations and relevant design standards. Consult structural guidance or a qualified designer for specific load-bearing requirements.
- Higher load-bearing capacity than C16 grade
- Suitable for longer joist and rafter spans
- Fewer knots and improved consistency
- Verify compliance with BS EN standards and building regulations
Moisture and environmental factors
Although kiln-dried and treated, timber will absorb and release moisture in response to ambient humidity. In very damp or wet environments, ensure adequate ventilation and drainage. The preservative treatment provides protection, but good construction practice—such as avoiding ground contact and ensuring water run-off—extends timber life significantly.
- Maintain good ventilation in enclosed spaces
- Avoid prolonged ground contact or standing water
- Ensure adequate drainage around outdoor structures
- Allow for natural timber movement in design and fixing