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
Hi,
Excellent informative web site!
I hope that you can help. We are building a porch which is clad in new oak with new oak posts. I have experimented with Sadolin woodstain and found that we prefer their heritage oak finish on this new oak. We also have a gable with 60 year old rough sawn oak barge boards and vertical planking which I’m guessing had been creosoted. We also have a new gable that will have new rough sawn oak fitted. I am attempting to see if we can end up matching the oak colours as near as possible on all three areas.
I have sanded an off-cut of the 60 year old oak to remove most of the black colouring which has revealed grey oak. I have then tried the Osmo Wood Reviver Gel that you recommended which has worked well so that we now have a light oak colour on the 60 year old oak.
I would like to know what you would recommend that we use on the 60 year old oak to both preserve it and colour it up to something approaching the Sadolin heritage oak colour and if the Sadolin product is suitable for sawn oak or whether there is something else that we should be using to both preserve and colour it.
Many thanks,
Ian
Reply to Ian:
Good Afternoon,
You could try a test area with the Sadolin to see if the match is close. It is likely that the rough sawn wood will absorb more of the Sadolin than expected and this could impact on the colour, its really difficult to tell until you do a test area. But if you are able to use the same product this is the best option for getting the colours as close as possible.
I appreciate that it has taken some time to get back to you and you may have completed your project but if you do need any advice please feel free to get in touch via our contact us (https://www.wood-finishes-direct.com/pages/contact) page.
Kind regards Samantha.
Hello and thank you for this informative site. In the 90’s my husband and I represented an artist in Russia who carved magnificent sculpture from (mostly) fallen, dried oak that he gathered by hand from a forest nearby. We sold many of his works over the years and now have about 20 or so remaining that we have not “treated or touched” since we first received them.
We are ready to present them in an art show / sale and would like to know how to best “clean” the works. Other than a gentle dusting. We know the artist told us all those years ago to do something like wipe them gently with a soft cloth and then use something (maybe tung oil?) to “quench the wood’s thirst”….. but this is a vague memory and my notes on the artist are difficult to find in time for this exhibition. He has since died.
He created sculpture out of other woods native to the forest near his home, as well.
I would dearly appreciate any thoughts you might have to share with me and if you would require photographs of a few pieces before being able to make a reply I can provide them,
Thank you,
Pat M.
Reply to pat:
Hello Pat,
I would certainly love to see some of the sculptures, photos can be sent to helpme@wood-finishes-direct.com if you get chance.
In terms of how to clean and protect you could have a look at the Barrettine Mould and Mildew Spray (https://www.wood-finishes-direct.com/products/barrettine-mould-and-mildew-spray) This will eliminate any fungal spores before applying an oil. Wood oils are quite versatile and can be used on a number of different wood types. I highly recommend doing a test areas first, and with each sculpture if it is a different wood, to ensure that you like the finish achieved.
Wood oils will darken the wood slightly giving it an almost damp like appearance which will also enhance the natural colour and character of the wood. I hope that helps but if you do have any questions please do not hesitate to get in touch via our contact us (https://www.wood-finishes-direct.com/pages/contact) page.
Kind Regards Samantha.
Hi,
I am excited to find this website as I have been wondering how to treat our oak front door for years.
The door is very likely as old as the house so 1932. The outside faces north and is reasonably well protected from rain and direct sunlight.
The outer surface is silvery and faded, though not much in the way of black deposits. In places when I draw a finger across the grain it is a little uneven.
I did try sanding it down but the sand paper kept clogging with wax, so I imagine it was previously treated with a wax preparation.
If possible I would like to find a treatment to restore the natural colour and protect it for the future. The inside of the door is in much better condition and a rich mid brown. Again I think it was wax treated.
The door knocker is probably brass and there is no reaction around this, but the letterbox surround, lock and handle are likely black painted iron and there is increased whitening around these. Would you recommend replacing these with brass? I have read that ferrous metals and oak don’t go well together.
Many thanks,
Gavin
Reply to Gavin F:
Good Afternoon Gavin,
If it is a wax you have on the door then you could first look at removing this with Woodleys Wax and Polish Remover (https://www.wood-finishes-direct.com/collections/stripper) this will strip away all then waxy finish currently on there and you could then consider the Osmo Wood Reviver Gel (https://www.wood-finishes-direct.com/products/osmo-wood-reviver) to restore the wood back to its original colour.
Once the exterior is clean and bare and as you would like it you can then consider which treatment you would like to finish the wood with for the best protection. For coloured oil finishes a recommended product would be the Osmo Natural Oil Woodstain (https://www.wood-finishes-direct.com/products/osmo-wood-stain-protector) colours and protects at the same time. And the darker the colour the more UV protection it will give. And you may be able to find a colour that matches the interior.
It is possible that the wood and metal used for the the lock and handle etc are reacting and I would be happy to take a look if you would like to send in some photos to helpme@wood-finishes-direct.com
I hope that helps and if you have any questions please do not hesitate to get in touch via a contact page contact us (https://www.wood-finishes-direct.com/pages/contact) page.
All the Best Samantha.
Hi,
Great website, very informative.
I would be grateful for some advice:
I was forced to cut down a big old oak tree as it was dead and unsafe. Most of the trunk was rotten but we have managed to get some timber from it.
I have about a dozen pieces (approx 1.3m x 250mm x 65mm) that I would like to use as windowsills in a new cottage that I am building now.
As I don’t want to wait ages for them to air dry, what is the best thing for me to do to be able to use the timber straightaway? I know builders often work with green oak, but for windowsills I am concerned that if I use it as it is it will shrink away from all the edges, but am not sure if trying to get it kiln dried is a good idea either (assuming anyone would even do a small job like that!)
Any advice would be appreciated!
Thanks.
Reply to Debbie:
Good Afternoon Debbie,
Green Oak will shrink and move as it dries naturally, it can crack and age and this is why many people like using it but for window sills this could be a problem over time and my advice would be to allow the wood to weather. And as a guide it is estimates that 25mm will dry per year which show just how long it takes for wood to naturally dry.
I do not know if kiln drying is a service that you are able to get as you say but we do not recommend application of anything during this drying process either.
I know that these are not the answers that you may have been hoping for but if there is anything further that I can help with please do let me know.
Kind Regards Samantha
Hi
We have just had European Oak window sills fitted internally and would like to protect and finish them.
From other posts related for window sills it seems that a coat of Osmo Wood Protector 4006 followed by Osmo UV Protection Oil 410 will be ideal for indoor conditions.
Can you confirm these 2 products please?
Thanks Barry
Reply to Barry M:
Good Afternoon Barry,
Thank you for your question. The Osmo Wood Protector (https://www.wood-finishes-direct.com/products/osmo-wood-protector) and the Osmo UV Protection Oil (https://www.wood-finishes-direct.com/products/osmo-uv-protection-oil-410) will be the perfect combination for your project. It will ensure the the wood is super moisture repellent and slow down the silvering process if the wood is particularly exposed to sunlight.
The Oil will require just two coats very thinly applied and as with all of our products I do recommend a test area first.
If there is anything further that I can help with please do not hesitate to get back in touch.
All the Best Samantha.