Osmo WR Base Coat (4001)

  4.7/5.0 (62 reviews)
1 coat = Recommended
Total: enter area

Wood type and application method can vary coverage.

  • New improved formula that replaces the old Osmo WR Base Coat 4005
  • Recommended in conjunction with exterior wood oils
  • Protects against mildew, rot, blue stain and wood boring insects
  • Greatly extends the life of softwoods and pines such as spruce, fir and hemlock
  • Penetrates deeply into the wood to repel water and reduce the risk of swelling and shrinking
  • Prevents swelling and shrinkage of timber
  • Dries to a clear finish
  • A unique combination of oil and water
  • Low odour formula
Brand Osmo
No. of coats 1
Coverage Up to 8 per litre
Drying time 12 hrs
Size 125ml, 750ml, 2.5L
MPN 4001A, 4001C, 4001D
GTIN 4006850103959, 4006850101863, 4006850101870

Osmo WR Base Coat (4001) is an exterior wood preservative that require protection against blue stain (EN 152), wood rot (EN 113) and wood-destroying insects (EN 46). It can be used on most exterior wooden surfaces including windows, frames, roller shutters, doors, pergolas, trellis and garden furniture.

Wood to be protected must be dimensionally sound and stable and not in direct contact with the ground.

  1. Wood surface must be clean, dry and frost-free (moisture content max. 20%) prior to application of Osmo WR Base Coat
  2. Clean old microporous stains thoroughly
  3. Old paints and lacquers must be completely removed to expose clean, bare wood
  4. Degrease bare wooden surfaces with meths if required

Always do a test area before starting any project to check suitability and compatibility. Stir well before use. Osmo WR Base Coat is ready to use and does not require thinning.

  1. Apply WR Base Coat by brushing, dipping or flooding
  2. Only spray apply in an enclosed unit
  3. Coat the clean, dry and frost-free wood generously
  4. Apply to all sides of the timber before fitting if possible

Please Note: This product is not for use on wood which comes into direct contact with food or animal feed. Also not for use in living spaces or habitable rooms. Do not use in immediate proximity of any kind of water.

Osmo WR Base Coat is intended as a protective base coat for exterior oil based products. It is therefore essential that it is over-coated with either an Osmo exterior wood oil or other suitable exterior wood oil.

62 customer reviews
Excellent by David Rollin

I bought this to apply a first 'primer' coat to my new 5 foot Alexander Rose garden bench. I was worried the 125ml tin was too small however it was just enough to coat all parts of the bench. It is a brilliant product.

Reviewed 125ml on: 21/05/17
Excellent coverage and ease of application by Mark Sheridan

Applied to the decking with a paint brush goes on very easy almost like water, covers an awful lot of decking 30square meters in my case

Reviewed 2.5L on: 21/05/17
Good result by Cms

Good coverage and really sinks into the wood.

Reviewed 2.5L on: 20/05/17
Another extraordinary Osmo product Looks a bit odd, works like a dream, I wouldn't think of using anything else by Jonathan Mitchell
Reviewed 2.5L on: 20/05/17
Sticky for a good few hours but waterproof imediately ! by Mr Neil Caunce

Goes on well - dries leaving a wet wood finish was waterproof immediately . Looks really good on larch

Reviewed 750ml on: 28/04/17
Good by David Brighton

great product

Reviewed 125ml on: 22/04/17
Clever stuff, I love Osmo products, almost feels like cheating - easy to use and work very well! by S Shard
Reviewed 750ml on: 20/04/17
Not applied yet as it is not clear that this is the best product for my exterior table to by Mr JATINDER SAHOTA

Not applied yet as it is not clear that this is the best product for my exterior table to

Reviewed 750ml on: 29/03/17
A note from us...

Hello Mr Sahota,

If you need any advice on the product or your project please feel free to give us a call on 0800 7818 123 and one of our friendly advisers will be happy to help.

Kind regards Samantha.

Very successful product Performs exactly to the requirements it is specified to address by Andrew Clark

The product is a very good one which is appropriate for the job of protecting the wood without destroying its natural look. Its performance in UV screening and waterproofing the wood finish is all that was expected of a product of this quality.

Reviewed 750ml on: 17/03/17
Just used so won't know yet if it does what it should It goes on easy, its almost like water, but it means it soaks in deep to protect wood by Ian Robinson
Reviewed 750ml on: 21/02/17
Again easy to apply by Mr Neil Caunce

Again aplied with a foam roller for speed - went in good and deep !

Reviewed 2.5L on: 11/01/17
Primer for Yew table by Andrew Hird

Fine. No problems to apply. Container was covered in German writing. I need a translator to decipher what was said on the tin.

Reviewed 125ml on: 08/12/16
As described by Mr R W Marsden

i found this rather thin,so care should be taken in its application.

Reviewed 750ml on: 04/12/16
Easy to apply! by Stephen Lawley

The Osmo base coat is easy to apply by brush and soaks into the wood for first stage protection. You must put a top coat of an oil based product on top (I used the Osmo UV protection oil on cladding that I want to retain the colour of) but the base coat is the right first stage treatment.

Reviewed 2.5L on: 10/11/16
Easy application, time will tell for success by Robert Ashdown

After spending hours researching which wood preservative to use I decided on Osmo WR4001 with a clear top coat for my log cabin. The product is easy to apply. Only concern is every where on the internet states a single coat but the tin states for best results 2 coats. Purchased from wood finishes direct who offered an excellent service. They were very informative and helpful. I will definitely be using them to purchase my top coat.

Reviewed 2.5L on: 06/11/16
Easy to apply by Phillip.downham@gmail.com

Easy to apply and completely colourless. Too early to say if it provides the protection promised.

Reviewed 750ml on: 23/10/16
Excellent product, really easy to use and is as described by James Donovan
Reviewed 2.5L on: 19/10/16
Have not used it yet; am still rebuilding my decking by John Taylor

Have not used it yet; am still rebuilding my decking. However using it as a base coat on my new decking should make be great for added longevity of the overall structure.

Reviewed 2.5L on: 17/10/16
Easy to apply Soaks in and drys really well by Julian Marshall

It is extremely runny so covering up any surfaces nearby is essential. It drys quickly but it is essential to have cleaned off any ingrained dirt before application as it will not soak through that! I am yet to see what the Osmo top coat looks like but having used Osmo products for several years I am sure it will look great

Reviewed 750ml on: 09/10/16
Good stuff by Tim Goffe

See my more detailed comments for Osmo Country Colour Dove Blue for a garden Playhouse project.

Reviewed 750ml on: 16/09/16