Welcome to part 2 of our series on wood types. This week I’ll be discussing oak & oak wood treatments. If you haven’t already read part 1, feel free to go check it out here: All about Pine Wood.
A Little History of Oak
Oak (or quercus as it is known in Latin) is a hardwood with some 400 known species. It has always been a popular wood in the UK, but in recent times it is even more widely used in construction and also as internal fixtures in clubs and gyms etc. For furniture construction, oak has become ever more the wood of choice, a trend expanding year on year since the year 2000 when China, India and Indonesia substantially increased their export markets. Pine has been the wood to suffer from oak’s popularity as it is more widely available in the Far East.
The flowers of many oak trees are known as catkins and they are produced by oaks when they reach their reproductive age, which is typically around 20 years. They are triggered by rising temperatures in spring. Ultimately it is the catkins of many oaks that turn into the acorns, so maybe that popular phrase… ‘mighty oaks from little acorns grow’ should be ‘mighty oaks from little catkins grow’, although it doesn’t quite have the same ring, does it?
Acorn of the mighty oak tree.
Treating Oak Wood
With regard to finishing and treating oak, there are numerous possibilities, but there are certain requirements that are asked for time and again… Often we are asked how external oak can be kept looking natural. Whilst the question is easy, the answer is not so straightforward. These are the necessary considerations:
- When water penetrates oak, it reacts with the high tannin content within oak, resulting in ‘blackening’.
- The sun’s UV rays will turn the oak to a silvery hue over time.
- Clear products are inevitably not completely clear, so they tend to ‘bring out’ the natural colours of the oak, normally making it a bit darker and warmer.
- The levels of rain, wind and sun will make a difference to how quickly the oak changes colour.
Oak turned grey/silver by UV rays & water damage.
Oak barrels traditionally used for whisky and beer.
If the requirement is to keep the oak looking as natural as possible, whilst preventing blackening or silvering as much as possible, then the following is the best system we know of:
- 1 coat of clear wood preservative
- Followed by 2 coats of Osmo UV Protection Oil 420 Extra
Osmo 420 Extra offers UV resistance and also contains biocide which is important for external timbers as it prevents the wood from becoming diseased with wet rot, dry rot and blue stone etc. The oil also repels water, thus preventing it from going black.
If the requirement is to protect the oak whilst keeping the silvery appearance, then the following is the best:
- 1 coat of clear wood preservative
- Followed by 3–5 coats of high-quality tung oil such as Morrells Tung Oil
Tung oil is one of the clearest oils on the market and doesn’t offer UV resistance.
If the exterior oak needs to be coloured, then the following system is recommended:
- 1 coat of clear wood preservative
- Followed by 1 coat of your chosen colour of Osmo Natural Oil Woodstain
- Followed by 1 coat of clear Osmo UV Protection Oil 420 Extra
If blackening on exterior oak needs removing, then scrubbing with a fungicidal wash such as Barrettine Mould and Mildew Cleaner is recommended. On the other hand, it may be the silvering that needs removing. If so, a scrub with Osmo Wood Reviver Gel (which contains oxalic acid, amongst other active ingredients) is recommended.
Unfinished oak.
Treated oak.
One of the most common enquiries we get is how to keep internal oak looking natural. This is not just a case of simply applying ‘clear products’ as they bring out the natural colours of the wood, thus making it a little darker and more golden. A very good indication of how your oak will look once it has been finished with a ‘clear’ coat is to dampen an area by applying some water with a clean cloth or sponge. The look achieved when the wood is damp/wet is very close to how it will look once a clear varnish or a clear oil has been applied.
Some customers like the way oak colours when clear coatings are applied to it, whilst others want it to be as close as possible to how it looks in its natural state. A more natural look can be achieved by using wood oils that have been specifically formulated to retain the natural appearance of interior oak. These products include:
- If an oiled finish is preferred, then apply two thin coats of Fiddes Hard Wax Oil Natural or Osmo Polyx Oil Raw.
- If a varnished finish is preferred, then 1 part Manns Classic Wood Dye can be mixed with 50 parts Manns Extra Tough Interior Varnish.
Clear wax polish is the one exception to the above… If a clear wax polish is applied to bare oak (or just about any other wood for that matter), then the colour is kept very natural indeed. It’s just a question of whether a wax polish is going to be durable enough. Internal doors, for example, are considered, by most people, to be ideal for finishing with wax, whereas a floor will look nice once waxed but regular maintenance is required, so most people don’t opt for wax for this reason.
If the oak needs to be made darker, then Osmo Polyx Oil Tints or Fiddes Hard Wax Oil Tints are ideal because they colour and protect the wood in the same application. It is always good to try and finish with a clear coat if possible because if the wood gets scratched, it is the clear coat that scratches before the coloured coat and therefore the scratch is not as noticeable.
Oiling Consideration
If oak is being oiled, it is a good idea to sand it with sandpaper that is no finer than 150 grit. The reason for this is that the pores of the wood are more open, thus allowing the oil to sink into the wood better. Better absorption equals greater protection.
Interesting Oak Stats
- Oak bark is rich in tannin and is used by tanners for tanning leather.
- Acorns can be used for making flour or they can be roasted for making acorn coffee.
- Tannin dissolves and escapes from the wood. Wine barrels are made from oak and it is the tannin that helps to give the wine its colour.
- Sessile oaks of Europe can reach heights of up to 40 metres.
- Oak trees regularly live to be 500 years old, although 1,000-year-old oaks are also known.
- A mature oak tree can produce up to 50,000 acorns!
Need help finishing a project made with oak?
For more help and advice on how best to finish oak, contact our team of resident experts who are always on hand to help with project advice and product recommendations.
We love to see before, during and after photos of any wood finishing project. If you would like to share your project pictures with us and our followers, you can either send us some photos or share on our Facebook, Twitter, Pinterest or Instagram pages.
469 comments
Reply to Samantha Taylor:
Hi Samantha,
I have read about Bona traffic for oak floors but can this be used on internal desktops and benches that are oak and have had a two pack finish applied(suspect it might have been oil based). I would like to get back to the original very light color of the wood.
Reply to Mary:
Hello Mary,
Thank you for getting in touch with your enquiry. Bona Traffic HD will normally have very good adhesion to pre-varnished flooring, however, it is advisable to check the intercoat adhesion prior to overcoating. To check intercoat adhesion, apply a coat of Bona Traffic HD to a pre-prepared area. Allow the coating to set for 3 days then scratch the treated floor surface gently with a coin. If the Bona Traffic finish stays firmly attached to the surface, the adhesion is satisfactory and the main application can begin.
It is a viable option to use the Bona Traffic on desktops and benches, however it is a very durable product and designed to be used on commercial flooring, there are alternate options that may be more cost effective for projects such as furniture and if you would like any advice on these please do not hesitate to get in touch via our contact us (https://www.wood-finishes-direct.com/pages/contact) page.
It is also unlikely that the Bona will lighten the desks or benches when applied over the top of an existing finish, to do this you are likely to need to sand back to bare wood and then you could also consider and option such as the Fiddes Hard Wax Oil Natural (https://www.wood-finishes-direct.com/products/fiddes-hard-wax-oil-oak-lightening) a penetrating oil that gives a natural look and feel and maintains an almost untreated appearance on the wood.
I hope this helps and please do get in touch if you have further questions.
Kind regards Samantha.
Hi there
We have just sanded our engineered oak floor.
It’s come out unfinished and really light.
We love the colour and want to leave it as light as possible. We understand that it’s not a light wood but is there anything we can do to seal it and keep it as light as unfinished looking as possible?
Thanks so much
Reply to Fran:
Hello Fran,
We often hear from people who have sanded their floors and found the natural tones to be beautiful, and so want to be able to maintain that very natural and light appearance. We have two products that you could have a look at for this, the first and most popular is a Hard Wax Oil that has a minute amount of white pigment in it, that counteracts the darkening you get with a clear option. From Osmo Osmo Polyx Oil Raw (https://www.wood-finishes-direct.com/products/osmo-polyx-oil-raw-3044) and from Fiddes Fiddes Hard Wax oil Natural (https://www.wood-finishes-direct.com/products/fiddes-hard-wax-oil-oak-lightening) these can help achieve that almost untreated appearance. As oils the penetrate the wood surface and give a very natural look and feel. Sample sachets are available for test areas and I would recommend these to ensure you are getting the desired result.
If you have a thorough read up of those products and do feel free to get back to me if you have any further questions via our contact us (https://www.wood-finishes-direct.com/pages/contact) page.
Kind regards Samantha.
Hi We have an external oak front door which was installed two years ago. We have a river in front of the house and the door is exposed to wind/rain and field flooding. The door was treated with Osmo but moisture has got in underneath the “laquer” surface and created mould/mildew black staining. So we sanded off the osmo and treated with Oxalic and have now got the natural slightly silvered colour back. To avoid the same thing happening again and especially to prevent the door absorbing water and swelling, we thought to use a natural solid bees wax or a soap to
treat the door rather than an oil or varnish. Is this likely to work or should we use a wood preserver and then tung oil?
Reply to Matthew W:
Hello Matthew, I would have to recommend sticking with the oil for your door. Oak is a long lasting and tough wood, when its quite new it will naturally leech tannins, this can happen for up to around 5 years. The tannins are dormant in the warmer months and become active in the winter, and is like candy for mould spores, the dampness will also encourage this.
You are able to deal with this effectively however and with a regular wipe down with Methylated Spirits and the use of a cleaner such as the Osmo Decking Cleaner (https://www.wood-finishes-direct.com/products/osmo-decking-cleaner-8025) will greatly reduce the problem.
And I would also recommend the application of the Osmo WR Base Coat (https://www.wood-finishes-direct.com/products/osmo-wr-base-coat) before the oil as this will further help to prevent mould build up. And then two thin coats of the Osmo Oil.
Any horizontal details and the lower part of the door are always the areas to be effected first and so keeping an eye on these areas will let you know when maintenance and cleaning is needed.
I hope that helps and if you have any questions at all please do not hesitate to get in touch via our contact us (https://www.wood-finishes-direct.com/pages/contact) page
Kind Regards Samantha.
Hello – thanks for such an informative blog! I don’t know where to start! I have two questions if I may:
1) I have reconditioned an old scaffolding plank into a bench. The plank was sanded down and turps applied before I used Osmo Polyx White Oil Tint from yourselves. The tint has dried buy made no difference to the appearance of the wood. Where did I go wrong?
2) I am looking to make some new planks into garden furniture. My plan is to trim down and then sand before applying the finish. I want the wood to be hardwearing, but I am not looking for a orange or glossy finish nor for the wood to turn silver over time. I would like the wood to stay raw looking and even have a white oiled effect if possible. What would you recommend?
Reply to Victoria Brouard:
Hello Victoria,
Thank you for getting in touch, I am happy to answer your questions. The Osmo Polyx Oil Tints (https://www.wood-finishes-direct.com/products/osmo-colour-foundation) in white is a very very subtle white finish, more slightly milky in appearance. i would say the lighter the natural colour of the wood, the harder it will be to see. It is not suitable for exterior wood work, however if your Bench is for the Interior it will be fine.
If you wanted a slightly more intense white result then I would recommend the Osmo Wood Wax Finish Transparent (https://www.wood-finishes-direct.com/products/osmo-wood-wax-finish-transparent) which has a higher pigment content. You would need to remove the current oil application however to make way for fresh oil. The white will be more visible, and still allow you to see the natural beauty of the wood and any grain pattern.
For your exterior wood you could again look at Osmo products, Osmo Natural Oil Woodstain (https://www.wood-finishes-direct.com/products/osmo-wood-stain-protector) has a wide range of natural colours and white. It is always better to apply a coloured oil, the pigments are far better for UV protection and reduce the natural silvering of the wood. And I would recommend a preserver be applied first to help prevent mould and decay, especially if the wood is not tanalised. Osmo WR Base Coat (https://www.wood-finishes-direct.com/products/osmo-wr-base-coat) is a good option to use with the Osmo Oils.
If you take a look at these options for your project and do feel free to get back to me if you have any further questions, and as always my advice is always to try a test area first.
All the Best Samantha.
Please can you help a complete newbie? I have 6 ‘pre finished’ (I think) Holdenby Oak veneered internal doors. I need to get them protected/treated/preserved against the general wear and tear of life. I am desperate to keep the colour as natural as I can. I think either Matt or Satin would be good (definitely not Gloss) I realise that some treatments might involve a little darkening but need to keep this to an absolute minimum.
The doors have arrived with instructions that only Osmo oil can be used to treat them.
Do I need to sand in between each coat? – if so which grade of sandpaper do I need?
Also how many coats would you advise?
Please can you suggest which would be the best product to use?
Thank you
Jan
Reply to Jan:
Good Afternoon Jan,
Thank you for getting in touch. The instructions have made it quite simple for you. If only Osmo is allowed then I can recommend the Osmo Polyx Oil Raw (https://www.wood-finishes-direct.com/products/osmo-polyx-oil-raw-3044) as the best option for your project. The Raw is designed to keep the wood looking as natural and untreated as possible. It has a minute amount of white pigment that counteracts the darkening you would get with a clear oil.
It comes in a sample size and I would recommend this for test area first, to ensure that you get the desired result.
If you take a look at this and feel free to get back to me via our contact us (https://www.wood-finishes-direct.com/pages/contact) page if you have any further questions.
kind Regards Samantha.
K