Why Does My Galvanised Wire Rust?
The Hidden Enemy in Your Fence: Why Galvanised Posts Might Be Failing Your Wire
When building a fence, we often assume “galvanised” means “indestructible”, however, many property owners are surprised to find their high-tensile wire snapping or rusting at the exact point it touches a galvanised post—often long before the rest of the fence shows wear.
The culprit is a phenomenon known as White Rust and it’s a significant limitation of traditional steel posts.
The Problem: Galvanised-on-Galvanised Contact
Galvanised steel relies on a thin layer of zinc to protect the steel core and for zinc to be effective it needs to “breathe” and react with carbon dioxide to form a hard, protective patina.
When wire is tied tightly against a galvanised post a moisture trap is created. This lack of airflow, combined with trapped dew or rain prevents the patina from forming. Instead, the zinc reacts with the water to create zinc hydroxide—that chalky, white powder known as White Rust.
The result? The protective zinc coating is rapidly eaten away, leaving the bare steel of your wire exposed to the elements. Once the zinc is gone, red rust takes over, leading to brittle wire and eventual fence failure.
The Alternative: Why EnduraPost Plastic Fence Posts & Pickets are Changing the Game
To solve the white rust issue many are moving away from steel-on-steel contact and opting for advanced modern technology like the EnduraPost plastic square picket. Here is how they compare:
| FEATURE | Galvanised Steel Posts | EnduraPost Plastic Pickets |
| Corrosion Risk | High (White rust at contact points) | Zero (Plastic cannot rust) |
| Wire Longevity | Reduced by chemical reactions | Extended (No metallic reaction) |
| Insulation | Requires plastic insulators | Self-insulating (Ideal for electric) |
| Durability | Can rust out at ground level | UV-stabilised and rot-proof |
| Maintenance | May require “cold-gal” touch-ups | Maintenance-free |
A Better Way to Build
While galvanised posts have been the industry standard for decades, the chemical reality of White Rust means they will unfortunately shorten the life of your expensive fencing wire.
By switching to a high-quality plastic picket like EnduraPost you will be investing in a fence that will go the distance whilst eliminating both metal-on-metal friction and the moisture traps that cause corrosion.
Call EnduraPost to find out more – you aren’t just buying a picket – you are making a long-term investment in the integrity of your entire fence… for the long run.
