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 Alan:
Hello Alan,
For ease of maintenance and the environmental factor, I would recommend the Osmo Ranges. These are made from natural oils and Osmo are ranked one of the highest for producing and packaging environmentally friendly products. For a clear protective finish there is the Osmo UV Protection Oil Extra (https://www.wood-finishes-direct.com/products/osmo-uv-protection-oil) very thin application is required and so a little goes a long way. It is easy to repair and maintain over time. Simply ensure the surface is clean and dry and then re coat with another thin application of oil.
Should you wish to add some colour Osmo Natural Oil Woodstain (https://www.wood-finishes-direct.com/products/osmo-wood-stain-protector) is a great option and is very similar to the product above. If there is anything further you would like to know or anything that I can help with please do not hesitate to get in touch or you can email me at wood@finishes.direct
Kind Regards Sam.
Hi Sam, we have a finished oak front door. It has black spores on it and has faded. How would I treat this to bring it back?
Many thanks
Reply to Shauna:
Hello Shauna,
Barrettine Mould and Mildew Cleaner (https://www.wood-finishes-direct.com/products/barrettine-fungicidal-wash-multicide) would be ideal for removing black spots and stains from the surface. Are you able to tell me what is currently on the door and if you are looking to retreat it as it is?
If you have a read up on the recommended product and let me know if you have any questions and I will be happy to help.
Kind regards Sam.
Hello could I have some product advice please.
Exterior- I have just had a green oak timber frame garage built with fresh larch cladding and exposed soft wood rafter feet. Also, a green and dried oak porch with a sheltered solid oak door. The porch is on the damper north side of the house. I was advised to either leave it all untreated to age over time or apply light creosote to keep it all an even colour.
I would like it all to remain one even colour and I’m concerned the wood may blacken with the damp. Can I seal new damp fresh oak?
Interior- How should i best protect the inside of the front door, porch frame, dried oak window boards, oak veneer internal doors and green oak beams? I would like to keep it all the same light/medium colour and limit the shrinkage and maintenance cycle. I’d rather not use a varnish that will need to be stripped off eventually.
Thank you for your help.
Ashley Green
07979647500
Reply to Ashley:
Hello Ashley,
For your exterior project I would recommend the use of a good quality wood preservative (https://www.wood-finishes-direct.com/collections/wood-preserver) to protect from mould, algae, mildew and rot. And then an exterior wood oil to give water repellency. Osmo WR Base Coat (https://www.wood-finishes-direct.com/products/osmo-wr-base-coat) is a great preservative to use under Osmo UV Protection Oil Extra (https://www.wood-finishes-direct.com/products/osmo-uv-protection-oil) which will prevent water penetration and protect the wood from UV damage.
These wood oil products will darken the wood slightly to give what we call the ‘damp look’. Exterior wood oils are easy to maintain as they simply need a quick clean and a top-up with a fresh application of oil as and when required, usually around 2 years dependent on weathering. Always do a test area before starting any project.
For the interior project, I would recommend Osmo Polyx Oil (https://www.wood-finishes-direct.com/products/osmo-polyx-oil). It is a durable, hard wearing finish that will give a close if not matching finish to the exterior treatment.
Both these oils soak into the surface of the wood allowing it to flex and move naturally. Both require very thin application and are easy to repair and maintain. If you have a read up on the products and let me know if you have any further questions, I will be happy to help.
Kind Regards Sam.
Hi Sam
Have recently had a new oak internal staircase fitted, like it so much that have decided not to carpet. I want to leave it looking natural and one of the fitters said to apply two coats of good lacquer but the other said varnish, What would you recommend,please
Thanks for any advice
Angela
Reply to Angela M:
Hello Angela,
Varnish and Lacquer are very similar in finish, they are both surface sealers creating a plastic like film on the surface of the wood. They are durable and hard wearing and I would recommend the Manns Extra Tough Floor Varnish (https://www.wood-finishes-direct.com/products/manns-extra-tough-floor-varnish) as a good option. It will darken the wood slightly and I would always recommend a test area first, to ensure that you are going to like the finish.
For a more natural look and feel to the wood I can recommend Fiddes Hard Wax Oil (https://www.wood-finishes-direct.com/products/fiddes-hard-wax-oil) which is a product that soaks into the surface of the wood. It is hard wearing although not as much as varnish, but is easier to maintain and repair over time.
If you have a look at the products that I have recommended and let me know if you have any further questions.
Kind regards Sam.
Hi Sam, I have an old oak secretary desk that was sanded, washed then oil with coconut oil. Unfortunately it was blackened more and more. Maybe 2 months since it was oiled. Will I need to bleach this? Thanks much, Alice
Reply to Alice:
Hello Alice,
Coconut Oil is a non curing Oil, it will not dry hard and so over time can start to go off or react to the air and go black. You should try wiping over with White Spirit (https://www.wood-finishes-direct.com/products/barrettine-white-spirit) to remove the oil. If this doesn’t remove it all then you will need to sand back what is left. This can be tested by wiping the wood with a slightly damp (not wet) cloth. Where the wood darkens due to the moisture penetrating the surface its safe to say the oil has been removed. If however the water does not darken the wood, it means that oil is till present and will require scrubbing with white spirit again and sanding.
Once you are back to bare wood I would recommend something like a traditional Tung Oil (https://www.wood-finishes-direct.com/products/morrells-tung-oil) or Danish Oil (https://www.wood-finishes-direct.com/collections/danish-oil) that will give better protection to the wood and will not go black. For better durability and longer maintenance periods, consider a hard wax oil such as Fiddes Hardwax Oil (https://www.wood-finishes-direct.com/products/fiddes-hard-wax-oil) or Osmo Polyx Oil (https://www.wood-finishes-direct.com/products/osmo-polyx-oil). I hope that helps and if you have any further questions please do let me know.
Kind regards Sam.
Hi Sam.
Great site and full of useful stuff !
I have had a new oak door (barn door style) fitted to back door and it needs a few joints filled before treating with Danish oil. Please can you tell me which of your products is best for filling in terms of colour matching and will take Danish oil
Thanks in advance.