22/05/2026
H3, H4, H5… confused? 🤔
You’re not alone. One of the biggest mistakes people make when buying a timber fence is choosing the wrong timber treatment level, and it can lead to early rot, weak posts, and expensive repairs later on.
Here’s the simple breakdown 👇
❌ H3 Timber
Designed for ABOVE ground use only.
Good for areas with minimal moisture exposure, but not ideal for fence posts or anything touching the ground.
✔ H4 Timber
Made for GROUND CONTACT.
This is the standard choice for most fencing posts in NZ because it’s treated to handle moisture, soil contact, and outdoor exposure.
✔✔ H5 Timber
Heavy-duty protection for extreme conditions.
Best suited for high-moisture environments, retaining walls, structural landscaping, and areas exposed to severe weather.
🌧️ Why does this matter in New Zealand?
NZ conditions are tough on timber:
• High rainfall
• Moisture changes
• Strong UV exposure
• Wind and ground movement
Using the wrong treatment level can dramatically shorten the lifespan of your fence.
That’s why choosing the right timber from the start is one of the most important decisions you’ll make.
💡 A properly treated timber fence doesn’t just last longer, it performs better in real NZ conditions.