4.87 from 1076 reviews

Osmo WR Base Coat (4001)

Additional resistance to water, fungal growth and woodworm, especially for softwoods. Made by Osmo 

  • For exterior use
  • Extremely water repellent
  • Resistant to blue stain, rot and insect attack
  • Reduces wood swelling and shrinkage
  • No future application necessary
  • Interior & Exterior Wood Primer

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Stephen W. ★★★★★ 25/08/2025

"Easy to use."

Info: Osmo WR Base Coat (4001)

Ideal as extra protection for softwood species for the exterior. A clear wood impregnation which serves as a preventive protection against blue stain, rot and insect attack. Penetrates deeply into the wood – prevents swelling and shrinkage and is extremely water repellent with a very low odour during application and is completely odourless when dry.

- Approx. coverage: 5-6m²/L with one coat
- No. of coats: 1
- Application temperature: 5°C
- Drying time: 12hrs.
- Sizes: 0.125L, 0.750L, 2.5L

- WR Base Coat is not a wood finish and is a base coat only.

- A finishing product from the Osmo range is required within three months.

- If possible, although not essential; apply to all sides of the wood to give the strongest protection. Wipe excess from edges with a dry cloth before leaving to dry.

- Some applications may raise the wood's grain, if neccessary de-nib to smoothen the surface.

- Use biocides safely. Always read the label and product information before use.

- Note: 4005 WR Base Coat Aqua was discontinued in 2016 and superseded with an improved oil-based version 4001 WR Base Coat.

Approx. coverage: 5-6m²/L with one coat

No. of coats: 1

ACTIVE INGREDIENTS: 1.2 % Propiconazole (12 g/kg) 0.05 % Permethrin (0.5 g/kg).

Downloads and documents

Technical data, safety data and application guidance for Osmo WR Base Coat (4001). All open in a new tab.

Technical data sheet

Safety data sheet (SDS)