You can leave your timber cladding uncoated to go grey but we don’t recommend it.
Regardless of species, treatment, application etc., timber is in fact hygroscopic - just like human skin.
And when you don’t take care of your body it will start to break down.
In Australia we have a wide and varying climate from; very high dry heat in Perth, to high humidity in Queensland, and (sometimes) wildly varied weather patterns in Melbourne.
So there is no set rule for what will happen to your timber, but below are a few typical outcomes.
High movement: particularly if it’s a timber species such as Blackbutt. When a finish is applied regularly, it restricts water entering the timber because there’s oil in the timber.
Mould and mildew: a quality oil will have a mould inhibitor built in. This is key to stop your timber going black which reduces the lifespan.
Surface cracking: like your skin, if timber dries out it will crack, often becoming unsightly. See image below.
A timber finish is more than just something to keep the timber looking fresh and stop it going grey.
A timber finish is a treatment very much like a hand cream - the timber needs to be kept hydrated and nourished.
How can you minimise maintenance?
If you’re looking to minimise the maintenance on your timber cladding and protect against decay, the best solution is Sioo:x Natural Wood Coating which weathers off to a beautiful silver-grey.
Sioo:x cures by reacting with atmospheric carbon dioxide and moisture to form an insoluble and flexible silica network within the timber surface.
The formation of this silica network toughens the surface of the timber and forms an effective barrier against insect attack and rot. With this new technology, a refinish is typically only required every 8 to 12 years. Read more here