Osmo WR Base Coat


Osmo WR Base Coat is a clear solvent-borne ready to use wood protection product for the exterior. It contains active ingredients which protect against wood rotting and wood staining fungi as well as against wood destroying insects. Osmo WR Base Coat 4001 penetrates wood easily and thereby gets deep into inner layers. This is ideal for use before applying a top coat for extra protection.

  • Use for additional protection against blue stain, rot and insect attack.
  • Extremely water repellent
  • Reduces wood swelling and shrinkage
  • No future application necessary

See Full instructions below

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SKU: OSMO_WRBASE Categories: , , , ,


Osmo WR Base Coat 4001 is a clear solvent-borne ready to use wood protection product for the exterior. It contains active ingredients which according to latest research protect against wood rotting (EN 113) and wood staining fungi as well as against wood destroying insects (EN 46). Swelling and shrinking is prevented. Osmo WR Base Coat has a faint odour during the application and is odourless after drying. Osmo WR Base Coat 4001 penetrates wood easily and thereby gets deep into inner layers. It is moisture regulating and provides an adhesive surface for subsequent treatment with finishing paints (top coat). It has a faint odour during the application and is odourless after drying.

Osmo WR Base Coat 4001 is a wood preservative for amateur use against wood rotting fungi, wood staining fungi and wood destroying insects on all outside wood which is out of direct ground contact and/or surface water e.g.: facades, windows (inner and outer parts), exterior doors (inner and outer parts), carports, shutters and balcony railings. Not for indoor application.

How to use Osmo WR Base Coat 4001

  1. Wood surface must be clean, dry and frost-free (moisture content max. 20%).
  2. Osmo WR Base Coat is ready to use, please do not thin.
  3. Stir well before use.
  4. Clean old microporous stains thoroughly. Old paints and lacquers must be completely removed. As a general rule, wear a dust mask during sanding works.
  5. Do not apply in damp conditions or if rain is imminent. Processing temperature: 10 – 30°C.
  6. Apply by (brush or roller) spreading out thinly and evenly along wood texture.
  7. 2-3 coats will be required depending on wood species and surface characteristics.
  8. Coat the clean, dry and frost-free wood generously – if possible on all sides.
  9. The product should be applied evenly in order to get best results.

Please note –

Reseal container after use. Do not allow this product to reach aquatic environments, the ground or the sewer system. Protect environment (e.g. soil, plants, aquatic environment) from splashes of Osmo WR Base Coat 4001.

Clean tools with Osmo Brush Cleaner (free of aromatic compounds).

Drying time is approx. 12 hours (normal climatic conditions, 20 °C/ 65 % rel. humidity). Lower temperatures and/or higher air humidity increases the drying time.

Coverage – 1 litre covers approx. 5-6 m² with one coat. Product coverage depends significantly on the character of the wood. All information refers to smooth and planed/cut surfaces. Other surfaces may lead to reduced coverage.

STORAGE – Up to 2 years and more if can is kept dry and closed tightly. If thickened by frost, store 24-36 hours at room temperature before use.

Osmo WR Base Coat is not to be used alone, instead it is a clear impregnation to protect wood against rot, blue stain and insect attack. It is compatible with all common types of glue and putty (except for silicone products). We recommend galvanized, anti-corrosive fasteners. To guarantee full protection (against UV rays) and the long-lasting beauty of wood, a top coat (e.g. with Natural Oil Wood stain or UV Protection Oil) is required after the impregnation has completely dried. If the coloured surface should have an external surface protection (film protection), we recommend for non-biocidal wood finishes (One Coat Only HSPlus and Country Colour) a top coat with UV Protection Oil Extra.* * Do not coat white finished surfaces with UV-Protection-Oil Extra.

The precautions generally recommended for handling wood protection products should be observed, e.g. wearing of protective clothing, safety goggles and protective gloves (e.g. nitrile rubber gloves). When using do not eat, drink or smoke. Handle product and dry freshly treated wood in areas with good ventilation. Keep freshly treated wood roofed or otherwise protected against rain until complete dryness. Do not breathe sanding dust. During application to in situ timbers and whilst surfaces are drying do not contaminate soil and surface waters with product. Keep out of the reach of children.

Questions and Answers

Can you use Osmo WR Base Coat as a finish coat?

WR base coat is as it says on the tin, a ‘base coat’ or ‘undercoat’ for wood and is not suitable for a top coat finish. You must add a top coat of the most suitable Osmo oil for your project within three months of applying the base coat for full protection of your wood. The WR base coat is for protection against wood rotting, wood staining fungi and wood destroying insects on soft woods like Pine. The top coat of Osmo oil will add protection against UV or weathering. 

Do I need to apply WR base coat to all woods before applying Osmo Oils?

No, you do not need to add this to all woods, just the softer wood species like Pine and Spruce. The WR Base-Coat is a clear finish that will penetrate deep into the softwood and this helps prevent swelling and shrinkage of the wood. Its water repellent properties add that extra protection needed on softwood that is prone to damage from the elements. 

Can you Spray WR Base Coat?

It is not recommended to spray this wood oil, as the use of the brush coat will ensure the oil will penetrate the wood correctly. With an Osmo flat brush, apply to all the sides of the wood and then the main body of the wood. You can de-nib any areas to smooth the wood if the grain has slightly raised but ensure you re-treat those areas. Always wipe away any excess oil with a lint free cloth if it has dripped or pooled in any areas.

Safety Data Sheets

Health and Safety

Risk mitigation measures this material and its container must be disposed of in a safe way. Do not contaminate foodstuffs, eating utensils or food contact surfaces. Wash hands and exposed skin before meals and after use. Keep in a safe place. Unprotected persons and animals should be kept away form the treated areas for 48 hours or until surfaces are dry. avoid all contact with plant life. cover all water storage tanks before application. all bats are protected under the wildlife and countryside act 1981: before treating any structure used by bates; consult natural england; scottishnatural heritage or the countryside council for wales. hazardous to bees. do not use on beehives or beekeeping equipment. 3-iodo-2-propynyl-n-butyl carbamate is a carbamate compound which has weak anticholinesterase activity. do not use if under medical advice not to work with anticholinesterase compounds. for outdoor use only.

CONTAINS Hydrocarbons, C10-C13, n-alkanes, isoalkanes, cyclics, May be fatal if swallowed and enters airways. Very toxic to aquatic life with long lasting effects. Contains 3-iodo-2-propynyl butyl carbamate. May produce an allergic reaction. Repeated exposure may cause skin dryness or cracking. Keep out of reach of children. Read label before use. If medical advice is needed, have product container or label at hand. Avoid release to the environment. IF SWALLOWED: Immediately call a POISON CENTER or physician. Do NOT induce vomiting. Store locked up. Dispose of contents and container in accordance with all local, regional, national and international regulations.

DISPOSAL INFORMATION  – Completely empty cans can be recycled as normal. Dispose left over product in the original container in compliance with local regulations. Do not dispose product residues or cleaning wastes into the sewer system (drains), into waterways or into the soil. Do not reuse empty containers. European Waste Code (EWC)-Code 03 02 02: organochlorinated wood preservative. 15 01 10: packaging containing residues of or contaminated by hazardous substances HSE: 10169 EXPIRY DATE: 2 years from production date

Additional information

Weight N/A

750ml, 2.5 Litres


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