You’ve just invested in a stunning new fence. The wood is a warm, golden honey colour. It looks perfect.
Then, six months pass. You look out the window and that rich gold has faded into a silver-grey. Is the wood rotting? Did the installer buy cheap timber?
The answer is no. This is a completely natural process. But the good news is, you can stop it (if you want to).
Why Does Wood Turn Grey?
The culprit isn't rain or snow—it’s the sun. Specifically, UV radiation.
Wood is made up of cellulose (fibers) and lignin (the natural glue that holds the fibers together). UV rays break down the lignin on the surface of the timber. As the lignin degrades, the yellow/brown color washes away, leaving behind the grey cellulose fibers.
This process is called "photodegradation," and it happens to every wood, from cheap Pine to expensive Oak and Cedar.
Option 1: Embrace the Grey
Before you run to the hardware store, ask yourself: Is grey actually bad?
If you have installed high-quality timber like Siberian Larch or Western Red Cedar, the "silvering" process is often desired. Architects love it because it looks natural and blends into the landscape.
Important: Grey wood does NOT mean rotten wood. As long as the wood was pressure-treated against rot, the grey color is just cosmetic skin damage. The core is still strong.
Option 2: Fight the Grey (The Right Way)
If you want to keep that "new wood" look, you need to apply a finish that blocks UV light. But be careful—most supermarket products are a waste of money.
The Mistake: Cheap "Clear" Preservative
Most cheap clear varnishes or sealants offer zero UV protection. They are like putting clear glass over the wood—the sun shines right through and bleaches it anyway. Within a year, the varnish peels, and the wood is grey underneath.
The Solution: UV-Protection Oil
You need a penetrating oil specifically designed with UV filters (think of it as Factor 50 suncream for your fence). Brands like Osmo or Restol are excellent. They contain pigments that are invisible to the eye but block the sun's rays.
- Pros: Keeps the natural wood grain visible; stops peeling; easy to top up.
- Cons: Needs re-applying every 2–3 years.
The Solution: Solid Stain or Paint
If you want zero maintenance for 5+ years, use an opaque wood stain (like a dark grey, black, or sage green). Because the pigment is solid, it blocks 100% of the UV light.
The "Do Not" List
Please, for the sake of your garden, avoid these common DIY errors:
- Don't use Motor Oil: An old myth. It is toxic to plants/animals and smells terrible in summer.
- Don't Jet Wash too close: High-pressure water raises the "grain" of the wood, making it fuzzy and more likely to absorb water. Use a stiff brush and a hose instead.
- Don't paint wet wood: If you paint a fence in winter when it's damp, you trap the moisture inside. This causes the wood to rot from the inside out. Wait for a dry spell in summer.
Too late to save it?
If your fence is already grey, mossy, and falling apart, no amount of oil will bring it back. It might be time for a fresh start.