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Owatrol H4 Wood

From £29.04

Waterproof Wood Sealer

Owatrol H4 Wood has been developed to protect and waterproof your exterior timber surfaces as it ages and becomes a natural grey colour without causing damage to the timber.


  • Water repellent – Protects surface against water ingress, mould, pollution, dirt etc
  • Hydrophobic – Repels water.
  • Hybrid system – Silicone Free.
  • Highly compatible – Can be overcoated with any finish (contact us) – Use as an additive (10%) in waterbased finishes to enhance their water repellent characteristics.
  • Non Film-forming – Allows wood to grey naturally while maintaining its internal structure.
  • Ideal for maintaining and protecting wood that has already greyed naturally.
  • Protects against everyday environmental attack – Prevents damage from weathering and UV rays.
  • Allows the transporting of timber in difficult conditions (containers, film wrapped pallets etc).
  • Does not change the colour. Appearance remains unchanged.
  • Easy maintenance – No pressure washing required.

Where to use

  • Exterior only.
  • Horizontal and vertical surfaces.
  • Softwood – Untreated and pressure treated.
  • Hardwoods – Exotic and broadleaved.

Surface Preparation

General Directions

  • Surfaces must be clean, dry and free of dirt, grease, grime, mildew and previous coatings.
  • Treat mildew with a 50/50 bleach/water solution. Scrub solution on to surface and allow to stand for 10 – 15 minutes; rinse thoroughly.
  • After cleaning and/or stripping, allow wood to dry 2-3 good drying days or until it has reached a moisture content of 18% or less before applying finish.
  • H4 Wood can only be applied to bare wood surfaces or weathered surfaces previously finished with H4 Wood .
  • H4 Wood may also be applied to surfaces previously finished with Owatrol penetrating products Textrol, Aquadecks etc without the need for stripping. Contact us for additional information and advice before proceeding. All other finishes MUST be completely and thoroughly removed.
  • If necessary sand surface after cleaning and/or stripping (80 grit paper).

New wood

  • Test wood for absorbency by sprinkling water on the surface. If water is absorbed quickly, the grain is sufficiently “open” and the surface is ready for finishing, proceed to Application. If water is not absorbed then proceed as follows:
  • Treat wood with Aquanett or dilute Prepdeck, neutralise with Net-trol, alternatively mechanically or manually abrade surface with 80 grit paper.
  • Clean and dust off to remove all loose wood particles.

Untreated weathered woods

1 – To keep grey look of the wood clean with N4.
2 – To restore colour of wood clean with undiluted Net-Trol to remove all loose wood fibres, dirt and other surface contamination.

Previously treated surfaces (oiled, paint, stain, varnish etc)

  • All previous finishes must be completely and thoroughly removed.
  • Oils and sealers: Strip with Aquanett or Prepdeck, neutralise with Net-Trol.
  • Solvent (oil or alkyd based finishes): Strip with Dilunett, neutralise with Net-Trol.
  • Acrylic finishes (Water-based): Strip with Prepdeck, neutralise with Net-Trol.

Other finishes i.e. 2 pack epoxies, urethanes etc

  • Strip with DSP 800, neutralise surface with a suitable solvent – Acetone, White Spirits, Methylated Spirits etc

Note: Hardwoods inc’ exotic hardwoods and woods rich in tannins i.e. Cedar, Douglas Fir, Teak, Ipe, Iroko etc may darken with Aquanett, Prepdeck and Dilunett, neutralising with Net-Trol immediately after rinsing will lighten and restore the woods colour. Oak and Chestnut please contact us for additional information and advice.


Coverage: 3 – 6 m² per litre
Application tools:  Brush, Roller, Spray 
Application temperature: Between 10°C and 30°C.
Drying: 1 hour
Clean-up: Soap and water.