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
I have just had two solid hardwood tree trunk tables delivered which are being used as side tables. They have their bark stripped and have been sanded down. The seller advised that they had been kiln dried but within 2 days of arriving they have started to grow white and green mound from the top and bottom of the stumps. Is there anything I can do to salvage them? They are lovely looking pieces are were quite expensive but obviously can’t have mould growing next to our sofas. Do you have advice? Many thanks!
Reply to Natalie:
Good Afternoon Natalie,
Thank you for getting in touch with your enquiry. This could just be the last of the moisture coming to the surface. A piece of wood this size will take a long time to dry out naturally and if kiln dried may have needed longer than it originally got. If you wipe over the surface with a Barrettine Mould and Mildew Spray (https://www.wood-finishes-direct.com/products/barrettine-mould-and-mildew-spray) to remove the current growth. And then you could look at treating with a wood preservative suitable for interior use (https://www.wood-finishes-direct.com/collections/wood-preserver) which will help to prevent mould and fungi from re developing.
This advised is based on the wood having no current treatments applied. The preservative is likely to darken the wood slightly and a test area is recommended to ensure you like to darkened appearance. You could also consider application of a penetrative oil to offer some further protection, although I would recommend doing this a little further down the line when you are sure the wood is fully dry and there will be no more mould issue.
I am happy to help if you have any further questions, please do not hesitate to get in touch.
All the Best Samantha.
Hi, I have an old oak bannister which has been sanded back. I applied one coat of boiled linseed oil with a brush, then wiped off any excess oil with a cloth. The next day I discovered parts of the oak have discoloured to a very dark black. I wanted to retain a natural looking colour for the oak. How do I remove the black areas? Thankfully I applied the linseed oil to the part of the bannister that faces the wall. Should I have used another type of oil eg Danish oil to avoid black parts? Kind regards
Reply to Brendan:
Good Afternoon Brendan,
It is rare but it does happen. Linseed can turn the oak and some other wood types, black. You can scrub with Barrettine Cellulose Thinner (https://www.wood-finishes-direct.com/products/barrettine-cellulose-thinners) and this will help to remove some of the staining, but any stubborn stains may require sanding back to remove.
As an alternative I would recommend a product such as Fiddes Hard Wax Oil (https://www.wood-finishes-direct.com/products/fiddes-hard-wax-oil) this is a much more durable finish that will be more longer lasting than the linseed oil, it only requires two thin coats. It will not turn the wood black, however it will darken to give the ‘wet look’. Sample sachets are available.
Danish oil is an option however this is mixture of natural oils and may contain Linseed oil also, and so you may find you have a similar problem.
I hope that helps and if you have any further 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.
We cut some fresh oak rounds about an inch thick to be used at a wedding reception on May 4. Can you please tell me the best way to keep the beautiful color. The rounds feel like they have some moisture in them. Do they need to dry first before coating with something? Any help would be appreciated.
Reply to D’Ann Karr:
Good Morning,
If the rounds still have a high moisture content then it is not advised to apply any product just yet. Ideally the wood needs time to dry out and as a guide an inch thick will take around a year to dry enough for a finish. If they are wet to the touch now it is unlikely that they will be dry for May.
However, you can aid this by leaving in a warm dry area or on the rare occasion that we have a warm/hot day putting them in the sun, this will help but rushing the drying process can result in cracking or warping.
As they are needed for May my recommendation will be to try a test application now on one, with something like the Osmo Wood wax Finish Extra Thin (https://www.wood-finishes-direct.com/products/osmo-wood-wax-finish-extra-thin) see if it soaks in okay and dries and if that works carry out the rest, but be prepared that long term the finish may fail, if you just require them for the wedding and the test works okay then it is a short term fix.
The Oil should penetrate the surface of the wood and will slightly darken and enhance the natural tones and grain of the wood. I hope that helps and if you 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.
I have an American oak staircase and American oak front door. Both Timbers were delivered and installed raw. I’ve recently hired a painter who has coated them with clear varnish. It appears that the varnish has dried out the timber and the timber is now looking a lot rougher than it originally was when it was raw. It appears the varnish may have dried the timber and someone looks like it’s splitting, dry and rough. Do you have any advice you can give me?
Reply to Vessy:
Good Morning,
Thank you for getting in touch with your question. I would not expect the varnish to have this impact on the wood and it will certainly not draw out any moisture from the wood. The wood may be drying out naturally and this is resulting in some shrinking and cracking. It may be worth getting in touch with the door manufacturer to see if the wood was stored some where damp, if you could also let me know which varnish has been applied to the wood and the method of preparation and application, I may be able to advice further.
Kind regards Samantha.
Hi,
I have built a new bathroom on the side of my house and have a false wall which houses the wall mounted taps for the bath. The wall is about 1200mm high and want to put a nice looking shelf on top to finish it off.. I am having some waned oak delivered soon to be used as the shelf ..
what can I use to protect it from the moisture in the bathroom whilst still keeping its original look?
Reply to Kevin:
Good Afternoon Kevin,
Thank you for your question. Often for Bathrooms I recommend the Osmo Wood Protector (https://www.wood-finishes-direct.com/products/osmo-wood-protector) this is ideal for bathroom areas that are exposed to humidity and temperature changes on a regular basis. It will darken the wood slightly however. And you are able to get an idea of this by wiping a damp cloth over the surface of the bare wood. It is superior at repelling moisture and is a base coat for an oiled finish with the Osmo Polyx Oil (https://www.wood-finishes-direct.com/products/osmo-polyx-oil)
To keep the wood looking as untreated as possible you could also look at the Osmo Polyx Oil Raw (https://www.wood-finishes-direct.com/products/osmo-polyx-oil-raw-3044) this has a minute amount of white pigment to counter act the darkening effect of a clear oil, however it can not be used with the Wood Protector as this darkens the wood and will defeat the object of using the Raw.
I hope that makes sense and helps but if you do have any further questions please do not hesitate to get in touch.
Kind regards Samantha.