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 Linda Bailey:
Hello Linda,
There are a couple of tests that you can carry out to help determine what is currently on there. The first is to put a small drop of oil, somewhere inconspicuous and leave it for 30 mins to an hour. If it remains unmoved then you are likely to have a varnish on the wood. If it moves or soaks in then you are likely to have an oil on it. You can also scrape a nail on the surface somewhere inconspicuous and see if any product comes away or it scratches easily this will indicate that you may have a wax on there.
Once you have established this I can give you further advice on how to move forward with your project. If its easier you can email me at wood@finishes.direct, reminding me of this post and any photos you may wish to add along with your test results. And I will be happy to help you further.
All the Best Samantha.
Hi!
I have bought an extendable solid oak table (sits 10, but extends at both ends).
It is now in our conservatory with has a floor-heating system.
My questions:
1] Oil to use on oak wood -
1.1 I have initially used Wood Silk with Bees Wax and purest oils (additionally, the product claims to be “the original non-silicone”. Should I continue using this?
1.2 If treating oak wood for protection, how often should it be done (no matter what product one uses)?
2] Table leaf extensions
2.1 Would table leaf extensions benefit from them being out (extended) all the time as I heard that wood should be allowed to “breathe”?; also so that the leaf extensions will ‘age’ and develop the same colour with the main table top?
3] Use of table leg pads
1] As I have mentioned earlier, the dining table stands in our floor-heated conservatory.
Is it necessary that I place table leg pads to protect the table legs from the floor heating? If so, where can I buy them? The size of the table leg each is 8-1/2 cms x 8-1/2 cms.
Our conservatory is north-facing, so there is no worry about the natural sun hitting the it all day (as I also draw the blinds to protect the table in the morning when the sun) for added protection from the heat.
Reply to Jo Stanbridge:
Hello Jo,
Thank you for your Enquiry, and to address the first question, a hard wax oil such as Fiddes Hard Wax Oil (https://www.wood-finishes-direct.com/collections/hard-wax-oil) is going to be a great option for your dining room table. And with a table that big I suspect you have a fair few dinner parties or gatherings and so protecting the wood from stains will be vital. The Hard Wax Oil is moisture repellent and durable, and should any stains or marks occur it is super easy to clean and patch repair. Top up coats will depend on how regularly the table is used, but I would not expect you to need to apply further coats for around 2-3 years.
The Wood Silk Non Silicone Furniture Polish with Beeswax, is not a product that I am familiar with, however I would not expect it to give as much durability as the Hard Wax Oil, rather a more aesthetic finish, and it may well prevent the oil from penetrating the wood. So removing all the polish before you apply any oil will be necessary. This can be done with Woodleys Wax and Polish Remover (https://www.wood-finishes-direct.com/collections/stripper) and Woodleys Finishing Pads (https://www.wood-finishes-direct.com/products/woodleys-finishing-pads).
You have stated, however, that the conservatory is north facing and has limited exposure so I would not expect fading to be a considerable issue for you. However, it would be fair to say that any areas more exposed to the sunlight will fade quicker than the more hidden areas. To maintain an even look to the wood it will be best to have all wood exposed equally and maybe turn the table every so often if possible.And finally in regards to pads for the table, I would not expect the heat to be an issue with the table legs, if oiled this will help to prevent drying out. The pads may help prevent possible scratches occurring during movement of the table and so although they will give some benefit may not be necessary. It is worth checking with the company who installed the under floor heating to see if they have any recommendations.
I hope that help and covers your questions, if there is anything further that I can help with please do let me know. Always try a test area first.
Kind regards Samantha
Hi, I’m thinking about using some 4" slabs of green oak I’ve found as kitchen work surfaces, but wonder how to finish them to withstand water/detergents in such conditions, bearing in mind green oak will need to shrink? I’d like quite a simple, rustic/dark finish to go in a simple Welsh cottage. Would appreciate your advice. Best wishes, Mark
Reply to Mark:
Hello Mark,
We tend not to make recommendations for Green Oak because of the high moisture and tannin content it usually has. Sealing it with a varnish will trap the moisture in the wood causing problems long term. An oil may not penetrate properly due to the high moisture content meaning that the wood will only have limited protection against marks and stains.
We nearly always recommend no treatment until the wood has dried to a more reasonable percentage such as 15 – 18 % and then you can consider products like Holzol Worktop Oil (https://www.wood-finishes-direct.com/collections/worktop-oil) or if a tinted or coloured finish is preferred, Fiddes Hard Wax Oil Tints (https://www.wood-finishes-direct.com/products/fiddes-hard-wax-oil-tints) or Osmo Polyx Oil Tints (https://www.wood-finishes-direct.com/products/osmo-colour-foundation) to give the protection you require.
These wood oils go a long way and must be applied very thinly to allow absorption.
I hope that helps and if you have any further questions I am happy to help.
Kind regards Samantha.
Hi Nick I am doing up a barn conversion and have oak external front door along with a farrow and ball blue windows.
I want the door to look as natural as poss and remain light.we done a test on Osmo uv natural the one with a white hint going through it and i thought i liked it so off we went and painted the door and the door frames and foot sills etc.
I hate it its made the wood go to red.it hasn’t completely dried yet its been on 4 days already tho so cant see the colour changing loads it would have to change drastically to make me like it.
What can i do?do i sand it all off and put Osmo raw on it which is for in door but will give me the look?if i keep on top of it will it not silver?
Reply to Ceri jones:
Hello Ceri,
If the product is not dry after 4 days this would indicate over application. The Oil is designed to soak into the surface of the wood and so requires two very thin coats. Any that does not absorb, sits on the surface of the wood and will have a very slow drying time, it will also not be as effective in its protection. I would recommend removing the excess oil by wiping down with a good quality white spirit such as Barrettine White Spirit (https://www.wood-finishes-direct.com/products/barrettine-white-spirit).
The UV protection Oil Extra in Natural is designed to leave the wood looking as natural as possible, rather than changing the colour. It will bring out any natural tones in the wood and this may be why it has gone a little red in colour. The Interior product, Osmo Polyx Oil Raw (https://www.wood-finishes-direct.com/products/osmo-polyx-oil-raw-3044) is designed to give the same effect as the oil you have already used but for interior wood. I would not recommend it for exterior use.
If you wipe down with a cloth dampened with white spirit, see how it looks, you might find the finish more to your liking. Do this on a small test area first before doing the whole area. If you have any further questions please do not hesitate to get in touch.
Kind Regards Samantha.
Thanks so much Sam. Have emailed directly.
Hi
We’ve inherited an old trunk that I believe is oak and in the region of a hundred years old. It has a very dark brown stain/finish. We want to put it under permanent glass cover outside to store cushions/blankets. Is there a product you would recommend that doesn’t require us removing/sanding down the existing finish but would protect from condensation, mould etc?
Thanks so much,
Wendy
Reply to Wendy:
Hello Wendy,
Its difficult to recommend a product to go on top of the existing one without knowing what the existing treatment is. If you are able to tell me what is currently on there, and oil or varnish ? Then hopefully I will be able to advice you further. You can email me at wood@finishes.direct
There is also a small test that you can do, and that is to put one small drop of oil on the surface of the wood and leave for about 1 hour. It is remains unmoved then you have a seal such as varnish on there. If it moves or soaks in then you may have an oil or the previous treatment has worn away. Feel free to sent me some photos if you think that may help.
Kind regards Sam.