Timber Grades Explained: C16 vs C24 & When to Use Treated or Untreated Wood

Timber Grades Explained: C16 vs C24 & When to Use Treated or Untreated Wood

🪵 Choosing the Right Timber: A Simple Guide

If you’re planning a building or landscaping project, picking the right timber makes a big difference. Whether you’re framing a wall, building decking, or replacing fence rails, it pays to understand the basics.

🏗️ C16 vs C24 Timber: What’s the Difference?

C16 Timber

  • More common and cost-effective

  • Great for indoor framing, fencing, decking

  • Perfect where load strength isn’t critical

C24 Timber

  • Higher strength and better quality

  • Ideal for structural jobs like roofs and floor joists

  • Less likely to warp or crack

💡 Tip from Kelvin Timber:
If you’re building something that needs to last, C24 is often worth the upgrade.


🌧️ Treated vs Untreated Timber

  • Treated Timber is pressure-treated to resist rot and insects. Use it outdoors – think decking, fencing, garden sleepers.

  • Untreated Timber is best indoors where it stays dry – great for furniture, indoor frames, or decorative projects.

🎯 Pro tip:
Don’t use untreated timber outside. It won’t last, even if you paint it!


❌ Common Timber Buying Mistakes

  • Guessing sizes – Always plan your cuts before buying.

  • Ignoring defects – Check for splits, knots, or warping.

  • Buying cheap from random suppliers – Always use a reputable timber merchant (like us!).

🧱 Need Help?
Our team can recommend the right timber for your job. Just ask us in-store or online. Contact Us


✅ Final Thoughts

Choosing the right timber can save you time, money, and hassle. At Kelvin Timber, we stock both C16 and C24, treated and untreated timber in a range of sizes – and we’re always happy to help you pick the right one.

👉 Shop Timber Now | 📞 Contact Our Team | 🛠️ Get a Quote

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