Fixing and buying guide
4.8Mtr X 47 X 100mm C24 Treated Regularised KD Carcassing Timber
Selecting the right size
This 47 × 100mm section is a standard carcassing size suitable for floor joists, roof battens, stud walls, and decking frames. The 4.8 metre length offers flexibility for most residential and light commercial applications. Consider your span requirements and load conditions when determining whether this section meets your structural needs.
- Check your building design calculations to confirm section adequacy for your application
- Account for any notching or drilling that may reduce effective section depth
- Verify that 4.8 metres suits your layout without excessive waste or jointing
Understanding C24 grading
C24 is a strength grade that indicates this timber has been visually or machine-graded to meet specific strength and stiffness requirements. It offers enhanced load-bearing capacity, fewer knots, and improved stability compared to lower grades such as C16, making it the preferred choice for structural applications where reliability is essential.
- C24 timber meets BS EN 338 standards for structural use
- Superior strength properties allow for longer spans or heavier loads than C16
- Consistent grading ensures predictable performance across multiple pieces
Pressure treatment and durability
This timber is pressure-treated with preservative to protect against rot, fungal decay, and insect attack. The treatment penetrates the wood fibres, providing long-term protection in both covered and exposed conditions. Treated timber is suitable for use in damp environments and outdoor applications where untreated timber would deteriorate.
- Treatment extends service life significantly in high-moisture or external applications
- Suitable for use in contact with the ground or in areas of high humidity
- Retains protective properties throughout the timber's lifespan
Handling and storage
Regularised and kiln-dried (KD) timber has been planed to consistent dimensions and dried to reduce movement. Store timber flat and level on bearers in a dry location, protecting it from direct weather exposure. Allow adequate air circulation to prevent moisture accumulation, which can cause warping or fungal growth even in treated stock.
- Stack horizontally with spacers between layers to allow air flow
- Keep away from ground contact and standing water
- Protect from prolonged direct sunlight, which can cause surface checking
- Handle carefully to avoid damage to edges or faces
Fixing and installation
Use appropriate fixings for your application—typically galvanised or stainless steel nails, screws, or bolts to prevent corrosion when used with treated timber. Ensure fixings are driven cleanly without splitting the timber. For structural applications, follow your building design and local Building Regulations requirements.
- Use corrosion-resistant fixings to avoid staining or degradation
- Pre-drill where necessary to prevent splitting, particularly near edges
- Ensure adequate bearing and support at all connection points
- Follow structural engineer's specifications for spacing and fixing methods