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 Colleen:
Hi Colleen,
It’s likely that the black in the wood is mould or algae, the same as you would find on wood around taps, sinks, baths and other damp environments. Black marks created by mould or algae can’t always be removed by sanding alone and should be treated with Barrettine Mould and Mildew Cleaner (https://www.wood-finishes-direct.com/products/barrettine-fungicidal-wash-multicide) once it has been sanded to kill off the mould or algae. One treatment should be sufficient but a second can be done if required.
In terms of re-finishing the table top, it depends on what product it was finished with originally. Do you know if it was a wood oil or varnish? You should be able to find out by contacting the manufacturer directly. Although you should be able to get a close match between the renovated table top and the rest of table, it can be difficult to get an exact match.
When you’re ready to re-finish the surface, do a small test area first to make sure that you are happy with the results that the finish gives before going ahead with the main project.
If you need any further assistance, feel free to contact us again via the blog or through the ‘contact us’ link on the main site.
Good Luck.
Hi nick.
I Have recently installed some fresh sawn feather edge oak cladding on a building. It’s over a dwarf brick wall which is also dressed in lead.
The issue we have had is that the tannin is running out of the oak and causing a massive amount of staining on the wall and lead which looks unsightly.
Before I do another part of the building and suffer the same fate, i wondered if there was a way of preventing this and if so what product would you recommend? It won’t be easy to retreat so ideally something which is a one off treatment. Ideally I want to completely seal the oak so none of the tanning can escape. It’s only a very small area I have left so I am even considering painting this last bit of oak if necessary as it’s a completely separate part of the building but given access issues I definitely don’t want any of this staining.
Thanks in advance for any assistance you can give a d great website.
Regards.
Ben
Reply to Ben:
Hi Ben,
Tannin that runs from the Oak is unfortunately a common problem.
I’m not aware of a full proof way of stopping this natural process i’m afraid. If you treat the wood with a wood preservative and then an exterior wood oil, it will go some way to reducing the Tannin flow but will not stop it completely. The alternative is an exterior wood varnish which may contain the Tannin better but can be problematic in future years. Exterior varnishes tend to crack and peel as they break down over the years, when this happens it can be a difficult process to fully remove the remaining varnish before re-coating.
Aged or weathered wood is the best option as the Tannin has largely been removed naturally by the elements, the wood can then be coloured and oiled with a product like Osmo Natural Oil Woodtstain (https://www.wood-finishes-direct.com/products/osmo-wood-stain-protector). This will protect and colour the timber but will still require maintenance in the form of a fresh coat every couple of years depending on the location of the structure.
Hi Nick,
Great tips on the website thanks :)
We have just finished installing a new kitchen and our builder made us a Tasmanian Oak timber frame for the stone bench top. Like a lot of the comments here, I want to protect the frame as best I can but still retain the natural look of the wood. I would prefer a matte, non-oily finish and could tolerate a slight deepening in shade but want to keep the natural look as much as possible. Can you please recommend how to best go about this?
I am in Australia so unsure if the same products are available here, but the types of products I need and how to apply them?
Many thanks!
Cain
Reply to Cain:
Hi Cain,
It’s always nice to hear that the information we provide on the website and blog is appreciated :-)
I believe that Tasmanian Oak has around the same density as many European Oaks so using a good quality wood oil is going to be a good option. Hard Wax Oils are available in a Matt finish and also dry completely so no ‘oily’ or ‘greasy’ surfaces. Using a standard clear oil will always darken the wood slightly giving it an almost ‘damp like’ appearance, it will also draw out the natural colour and grain of the timber which in some cases, can be very different from the bare wood appearance.
A way of testing the appearance that a clear oil will give is to slightly dampen the wood with some water on a cloth or sponge. This gives a fairly good representation of how the wood will look oiled without actually applying oil. Once the wood dries from being dampened, it will return to its original untreated appearance.
If you prefer to keep the wood looking more like it does in its natural state, consider Osmo Polyx Oil Raw 3044 (https://www.wood-finishes-direct.com/products/osmo-polyx-oil-raw-3044). This oil has been specifically designed to help maintain the ‘Raw’ appearance of timber while still offering the same level of protection as the standard clear Polyx Oil.
Osmo have a distribution network in Australia. Osmo Australia can be contacted here (http://www.osmoaustralia.com.au/).
It might be worth getting a small tester pot to try the product out first.
Always do a test area before starting any project.
Hi there,
Wondering if you could help me. I bought a whole range of dining room, livingroom furniture about 2 years ago from the Cambridge Oak range from Next in the u.k. It is predominantly solid oak with oak veneer. Last week I bought one more piece from the range which has been changed to Cambridge Light. I presume this is white oak they are using now in the furniture range. I love the new piece and the lighter colour oak and was wondering what I could do to lighten the rest of my furniture. Two years ago when I bought it, next recommended treating the oak with tung oil. I applied a couple of coats of this without thinning it for the first few coats with white spirits which it stated on the back of the tung oil bottle. I used Liberon pure tung oil. The furniture has darkened an awful lot in just 2 years and has an orangey look to it and I am really disappointed as I paid a lot of money for the range. Was it because I did not thin down the first few coats of tung oil that caused it to darken so much and is there anything I can do to lighten it without making a mess of it and ruining it altogether. Would appreciate any help you can give me and sorry for the long post, thanks
Reply to Nicola:
Hi Nicola,
Tung Oil, as with most types of wood oil, will darken the colour of the wood as well as bringing out the natural grain and colour of the timber. You should be able to remove most of the tung oil by wiping with white spirit which will break down and dissolve much of the oil, have plenty of dry rags to hand. a light sanding with a 120 grit sandpaper will then take you back to the bare wood. To keep the lighter appearance of the freshly sanded wood, consider 2 thin coats of Osmo Polyx Oil Raw 3044 or Fiddes Hard Wax Oil Natural. These will provide a good level of protection for your furniture while retaining the lighter colour of the freshly sanded wood.
As with any project, Always do a small test area on a low visibility section, perhaps the underside or back edge to be sure that you are happy with the results.
We’ve recently purchased a pair of salvaged solid oak old church doors which we’ve scrubbed, repaired and sanded, and which are now looking lovely. We want to finish them with a soft, subtle sheen but one which will also protect them against the elements. We do not want to end up with a hard brittle shine. Any ideas please.
Reply to Gordon Harradine:
Hi Gordon,
The best way to preserve and protect your church doors now that they have been cleaned and are back to bare wood is to first treat them with a preservative such as Barrettine Premier Wood Preserver Clear (https://www.wood-finishes-direct.com/products/barrettine-premier-wood-preservative). This will protect the wood from biological threats such as mould, algae, dry rot and insect attack. For the best results, apply 2 coats of preservative allowing at least 24 to 48 hrs drying time between coats and before applying an oil.
To protect the doors from the elements including wind, rain and sun, 2 coats of Osmo 420, UV Protection Oil Extra (https://www.wood-finishes-direct.com/products/osmo-uv-protection-oil) are recommended. This will enhance the natural grain and colour of the timber as well as darkening it slightly to give an almost damp, satin-matt finish.
Always do a test area first and follow the manufacturers instructions on the tin.
Hi Nick
Brilliant website, thanks. We’ve bought an old oak front door from a reclamation yard and have now stripped the outer side back to bare wood with a combination of varnish remover followed by hard scraping with an edge of a scraper held at right-angles to the wood, then sanding – phew! The weather board at the bottom is still darker (presumably it got more rain in its former life) but we’re happy with that character.
The door is in an enclosed (glassed in) porch, north-east facing, so won’t get any rain & almost no direct sun. We want to keep it looking as natural as possible with no shine, so I was concerned that the beeswax you suggested for Nicky might leave a sheen.
Any suggestions gratefully received.
Thanks
Steve R