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Osmo UV Protection Oil Extra

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Osmo UV Protection Oil Extra is a superior wood oil that protects timber against the greying effect of the Sun's UV rays by a factor of 12. It offers superb durability against weathering with an added biocide to combat insect attack and fungal growth.

Easily applied with a paint brush or velour roller Osmo UV Protection Oil Extra dries to a satin-matt finish that will not peel, flake or blister.

Can also be used for lightening or overcoating the Osmo Natural Oil Wood Stain colour range.

  • Prices
  • Overview

Osmo 420 & 425 Overview

Perfect for use on all exterior timber including external doors, window frames, windowsills, carports, timber cladding, balcony, screens & fences, pergolas, garden houses, furniture and more.

Osmo UV Protection Oil Extra has been designed to combat the greying effects of the Sun's UV rays on exterior wood. Can be applied to a wide range of exterior soft and hard woods including Pine, Larch, Teak, Oak and Bamboo.

Exterior timbers turn grey or silver over time as a result of exposure to the sun and rain. Osmo UV oil acts as a 'sun cream for wood' slowing the greying process by a factor of 12 when compared to untreated wood.

Osmo 420 Extra and Osmo UV Protection Oil 425 Oak also contain Biocide which helps to protect timber from the onset of mould, algae and insect attack.

These UV Oils are micro-porous, thus allowing the wood to breathe. As the oil penetrates into the surface of the timber, it doesn't form a surface coating, so will not crack, peel, flake or blister. Osmo 420 clear and 425 Oak penetrate deep into the grain aiding the natural elasticity of the wood and helping to reduce shrinkage and swelling.

Osmo 420 clear & 425 Oak - Key Features

  • Based on natural, renewable resources
  • Final finish protects against mould, algae and fungai attack
  • Oiled finish provides a microporous, breathable surface
  • Foundation and top coat in one
  • For use on dimensionally/non dimensionally stable exterior wood
  • Dries in approximately 12 hours under normal conditions
  • 2.5Ltrs tin covers approximately 45 square meters based on 1 coat


Ensure surfaces to be oiled are clean, dry and free from all surface coatings such as paint or varnish before application. Wood that has been previously oiled should be cleaned and lightly sanded.

New unpreserved or old wood should first be treated with a quality wood preservative such as Barrettine Wood Preservative or Ronseal Total Wood Preservative before applying Osmo UV Protection Oil. Using a wood preserver prior to applying the oil gives additional protection against mould, algae, dry rot, woodworm and other wood boring insects. Allow sufficient time for the preservative to dry, normally 24 to 48 hours, before applying 'Osmo 420 Clear' or 'Osmo 425 Oak'.

As an alternative to spirit based preservatives Osmo WR Base Coat 4005 can be used. This product penetrates deeply into the wood to help repel water and moisture. This helps to reduce the risk of timber swelling and shrinking therefore reducing the chance of the wood cracking, splitting and warping. Note: this product does not contain an active insecticide.


Apply in thin coats with a paint brush or velour roller ensuring that the oil is worked into the grain of the wood as opposed to painted on top of the wood. Always finish your brush or roller strokes by going in the direction of the wood grain. Osmo UV Protection Oil Extra 420 can also be applied over Osmo Natural Oil Woodstain as a top coat for added protection and durability.


Slightly tired looking areas can be easily refreshed by simply cleaning the affected areas and applying a fresh coat of Osmo UV Oil. Even badly scratched areas can be seamlessly repaired with a light sanding and a re-application of the oil.

Equipment Cleaning

Application brushes and other equipment should be cleaned with Osmo Brush Cleaner or White Spirit.


Osmo UV Protection Oil Extra has a shelf life of 5 years or more if kept sealed in the original tin. Store in a dry cool place. If thickened by cool temperatures or frost, the oil will regain its normal consistency within 24 to 36 hours of being returned to normal temperatures.

To preserve any remaining oil once the tin has been opened and used, decant any remaining oil into a smaller tin, jar or container, fill to the rim and seal with an air tight lid.


Osmo recommends that this product is NOT used on horizontal surfaces where water can collect such as floors, decking and wooden steps etc.


Q. We have a garden table which says only use Roble Wax and not Linseed Oil. I have searched for this product and even with the Internet I have not succeeded. The table was from B&Q. Please can you help me?

A. To my knowledge, it's only B&Q that offers the Roble garden furniture in The UK and the product recommended for finishing it is indeed hard to find. We have looked into this thoroughly and can confirm that Osmo's UV Protection Oil is ideal for Roble wood. As Roble is a dense, oily wood it is important to work the oil into the wood well and apply it thinly.

Q. I work for a joinery that makes and fits bespoke hardwood windows, doors and decking. Can Osmo UV Protection Oil be used on dense exotic hardwoods like Teak, Iroko, Ipe, Meranti and Garapa?

A. On the tin it states that Osmo UV Protection Oil Extra is not suitable for use on Iroko, Teak and other exotic hardwood timbers but we have customers that have used Osmo UV Protection Oil with success on these woods.

Lightly sanding with a 120 grit sandpaper helps to open the tighter, less porous grain of exotic hardwoods enabling the oil to penetrate easier. Wiping the timber down with methylated spirit prior to applying Osmo UV Oil can help to remove some of the natural oil from the surface of the wood which helps the Osmo Oil to penetrate. Ensure the oil is at a good room temperature as it thickens when cooler making application more difficult. Apply thinly working the oil into the surface grain of the wood.

Q. Can Osmo UV Protection Oil 420 Clear be used on garden decking?

A. Osmo says that this product isn't suitable for use on horizontal surfaces such as decking. This said however, we have customers that have applied one coat of Osmo Decking Oil then applied 2 very thin coats of Osmo 420 clear on top and have been happy with the results.

Drying Time

Osmo UV Protection wood oil dries in approximately 12 hours in normal climatic conditions of 23℃ / 50% relative humidity. Lower temperatures and higher humidity can increase the drying time.

  • Reviews

Osmo UV Protection Oil Extra reviews - Rating: 4.8 out of 5 stars, based on 212 reviews.

Filter:   All reviews (212)   5 stars (180)   4 stars (29)   3 stars (2)   1 star (1)  

Martin Stoner
 2.5L, Clear - 420 Extra
Excellent Product
Quality product with a quality finish, I used this along with the WR Base Coat on 3 new oak doors. Fantastic protection and finish soaks in well and brings the grain out. Will always use Osmo.
Kath Kibble
 2.5L, Clear - 420 Extra
I used Osmo oil when I first laid my oak floor, its so easy to apply and so natural. It leaves no residue like Varnish and when its time to revive the floor its simple no sanding just clean it and apply. I revive my floor every 2 years, it lifts it and looks amazing. The real beauty of Osmo oil is that you can touch up any areas you have missed when dry it blends in perfectly.
G Biggins
 2.5L, Clear - 420 Extra
Easy to use , on planed wood covers easily, but on sawn wood coverage was a lot less
John Brixton
 2.5L, Clear - 420 Extra
Go's on nice and easy
Best product you can buy for oak
J.B. 007
 2.5L, Clear - 420 Extra
Excellent Performance But Very Expensive!!
I previously used this on an external Oak Door and it gave just the natural wood appearance I was looking for - ie without any staining or darkening effect. Used it this time on some custom made contemporary fencing as a backdrop to a BBQ area and now it looks even more impressive. Easy to apply and gives outstanding protection. The only downsides are the price and the time it takes to apply.
Simon Pitchford
 2.5L, Clear - 420 Extra
Excellent product recommended by the joiner
Dries remarkably quickly leaving an excellent finish
Michael Sims
 2.5L, Clear - 420 Extra
First class product
Easy to apply,after two coats the finish was excellent .
Clare Borrett
 750ml, Clear - 420 Extra
Great product
Good coverage, lovely product, excellent for external use with a clear sheen.
 125ml, Oak - 425 Extra
Easy to use
I bought this to finish some fairly light coloured English oak. I was worried that it might make the wood too dark, but that wasn't the case at all. After one good coat of clear wood preservative I applied two coats of this as recommended, and it looks beautiful! All I will say though, is use it very sparingly. This is something that's designed to soak in, and not form a surface layer. If you do over do it as I did, then any residual oil can easily be removed using some fine wire wool after a few days drying time. This was for an exterior project and only time will tell how well this product works...
Richard Sowerbutts
 2.5L, Clear - 420 Extra
Seems to work on oak but the winter weathering will tell
An oily coating leaving natural wood colour. Still to see how it deals with winter weather; suspect it may need recoating annually.
Peter Dijkhuizen
 125ml, Clear - 420 Extra
OK so far but only on sample piece
Have applied but be aware that it needs to go on very lightly. Time will tell if the windows are protected and look good. I suspect the oak windows will be darker after application but I can accept this if maintenance is a lot less.
David Fowler
 2.5L, Clear - 420 Extra
It seems to work well
Does the job, we re-order all the time
Clyde Chainsaw Carving
 750ml, Clear - 420 Extra
Fast delivery , well packaged and great oil ( osmo uv exterior ) I wouldn't use anything else
Chris Sheahan
 2.5L, Clear - 420 Extra
Good value
Easy to apply. Good finish.
Jill Davidson
 750ml, Clear - 420 Extra
Excellent product
This wood protection is an excellent product which is used widely by tradesmen and easy to use
S Hickmott
 750ml, Clear - 420 Extra
Really good!
This oil is a joy to use, covers easily and protects well, can be a bit thick if the temperature is low, so keep warm just prior to using.
David Pennison
 750ml, Clear - 420 Extra
Easy to use
Easy to apply (applied to exterior oak door) Too early to say yet how good the UV protection is and therefor how long it will last, but it should be easy to re apply in the summer.
Lynda Gill
 750ml, Clear - 420 Extra
Was applied very easily
We like the UV protection, so hopefully our Oak will not turn Silver
Graham Ferris
 2.5L, Clear - 420 Extra
Really surprised how good this product is
One of the best oils for wood I have ever used. easy to apply with brush. Soaks in very quickly with first coat, Slower with 2nd. Looks good so far.
Paul Roditi
 750ml, Clear - 420 Extra
Goes in easily and dries waterproof.
So far I'm happy with thus product; easy to apply and brings out the beauty of the natural wood. It seems to seal the surfaces well, as water beads on it rather than spreading it is a microporous finish though, and only time will tell if it truly protects the woodwork from rain and sun (it has a sun screen in it!)

per litre
12 hours
dry time
  • Protects against greying
  • UV-Protection factor 12
  • Will not peel or flake

Coverage Calculator

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* Coverage can vary depending upon on the type of wood used and the amount of product applied. Litreage amounts shown above are total, not 'per coat' amounts.
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