Articles: Do you need to treat green oak?

Should I Treat Green Oak?

In short, no it is not necessary. This is because when using green oak you’re likely to be using it structurally or outdoors which is a circumstance where moisture movement does not affect its stability.

Whilst oak is very versatile and suitable for use in joinery, you would not use green oak. The only time we suggest treatment with oak is when it is kiln dried and may be exposed to moisture as this will prevent movement of the timber.

How should you treat Green Oak?

Green oak doesn’t require treatment to do its job even though overtime it will begin to dry out and create the characterful splits, cracks and surface checking that oak is known for. Additionally, the UV rays from the sun will cause the surface to go a refined silver-grey colour. This process is completely normal and does not affect structural performance.

Some customers prefer the look of oak before it goes silver-grey. The only way to do this is keeping it out of the sun or by using a UV protector treatment. Of course the former may be impossible for an outdoor structure which leaves you with treatment as the only option, which can be difficult.

We have had customers in the past attempt to treat their green oak beams fresh after receiving them but due to the moisture on the surface the treatment would struggle to take hold. The only way around this is to wait for the surface moisture to dry somewhat to allow the treatment to stick to the timber.

Should I oil green oak?

The treatment we usually recommend for UV protection is OSMO UV Protection Oil, suitable for external timber with protection against mould, algae and fungal attack. Additionally, it will also help prevent moisture movement of the timber which can slow down the effects of swelling and shrinkage.

If you're looking to treat your green oak, we recommend a company called They are the experts in timber treatment and they will provide you with all the necessary information to ensure you go with the right treatment for the job.

Another popular treatment our customers tend to use when treating exterior green oak is something called oxalic acid crystals. This is used to remove unwanted staining on the surface of a timber such as blue stain, blue staining is expected as this occurs when the timber comes into contact with ferrous metals leaving a dark blue mark. It can also remove markings from sap as indicated in our Treat My Timber page.