How and where to use guide
3.0Mtr X 47 X 175mm C24 Treated Regularised KD Carcassing Timber
Typical applications
This timber is ideal for floor joists supporting domestic and light commercial loads, roof battens and rafter work, stud wall framing for internal and external partitions, decking frames and substructures, and general structural carpentry. The C24 grade provides enhanced strength and fewer defects compared to lower grades, making it the preferred choice where load-bearing performance and reliability are critical.
- Floor joists in domestic and light commercial buildings
- Roof battens, rafters, and roof framing
- Stud walls for internal partitions and external cladding frames
- Decking frames and outdoor substructures
- General structural carpentry and framing
Indoor applications
For internal use in dry conditions—such as floor joists in domestic properties, roof structures, and stud walls—the treated timber provides long-term stability and protection against any moisture ingress or insect activity. The planed, regularised finish gives a clean appearance suitable for visible framing or where finishes will be applied directly.
- Domestic floor joists and suspended timber floors
- Internal stud wall framing
- Roof structures and attic framing
- Loft boarding and storage platforms
- Structural support for internal partitions
Outdoor and exposed applications
The pressure-applied preservative treatment makes this timber suitable for outdoor use, including decking subframes, garden structures, and exposed framing where it may be subject to weather exposure. However, the timber should not be used in ground contact or in permanently wet conditions. Ensure adequate ventilation beneath outdoor structures to prevent moisture accumulation, and consider additional surface protection such as paint or stain for enhanced weather resistance.
- Decking frames and substructures
- Garden structures and pergolas
- Exposed roof framing and eaves
- Outdoor building frames and sheds
- Not suitable for ground contact or permanent immersion
Installation best practice
Install timber with adequate spacing and ventilation to allow air circulation and moisture evaporation. Use appropriate fixings—such as galvanised or stainless steel nails and screws—to prevent corrosion and staining. Ensure joists and beams are adequately supported at bearing points, and follow building regulations and structural engineer specifications for spacing, sizing, and load distribution. Avoid trapping moisture between timber and masonry or concrete by using damp-proof membranes or ventilated air gaps where required.
- Maintain adequate ventilation around and beneath timber
- Use corrosion-resistant fixings (galvanised or stainless steel)
- Support at bearing points according to design specification
- Follow building regulations for joist spacing and sizing
- Use damp-proof membranes where timber meets masonry
- Avoid trapping moisture in cavities or enclosed spaces