Can you leave oak untreated?
Last week we concluded that treatment of oak is not entirely necessary unless it is kiln dried. You can if you wish to protect it from mold, algae, fungal attack and UV damage, but for the most part you leave it as it arrives fresh sawn.
Oak is an extremely low maintenance timber and sees use in many different construction projects. It can be installed straight from the log fresh sawn and then left pretty much untouched for decades. This is due to the potent, naturally occurring tannins present in the oak which bolster it against the elements.
Without treatment, oak will have a few aesthetic differences. As it stands throughout the seasons exposed to the elements, the surface of the oak will begin to shift to a refined silver-grey colour and develop its iconic splits, cracks and surface checking.
These aesthetic variations are completely natural and expected. The splits and cracks in particular are an indication of the oak becoming more durable as it tightens and shrinks into a more rigid structure, this is especially beneficial when using joinery techniques as this process will bring together and tighten up all of its joints.
Additionally, treatment doesn’t increase its longevity at all. Oak will stand firm for decades with or without treatment relatively maintenance free. This is one of the reasons why we specialize in oak, its just such a wonderful and versatile timber!
Do I need to treat Kiln Dried oak?
The process of kiln drying is to reduce the moisture content of oak down to a stable level and prevent any moisture movement. This is important when using the oak in joinery as you don’t want the pieces to warp, split or crack.
If used externally or in an area where it will be exposed to water then yes it is important to use treatment to seal the oak and stop moisture getting in. If it does, you’re likely to experience swelling and potential warping of the affected piece.