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High Performance Wet Rot Wood Hardener

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Stop wet rot spreading and make your wood hard again so it can be easily repaired. Suitable for doors, windows and frames. Can be used inside or outside.

  • Don’t replace rotten wood, repair it
  • Dries in two hours
  • Sets rock hard
  • Soaks in deep and strengthens rotten wood
  • Provides a strong base to begin filling cracks and holes
  • Sinks into rotten wood and repairs
  • Dry in 2 hours
  • Sets rock hard

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Use for the following wood types
  • Interior wood
    Interior wood
  • Exterior wood
    Exterior wood

1 colour available including:


How do I use it?

Number of coats

One coat


Brush on

Where to use it?

Any rotten interior or exterior wood

How to strengthen wet rot wood

Before you start

Wear protective gloves to avoid getting hardener on your skin. Open your doors and windows for added ventilation.

  1. Remove loose or crumbling wood and make sure the area is dry.
  2. For the best repairs, drill small holes into the wood so hardener can get in deeper.


  1. Give the tin a thorough shake.
  2. Pour some of the hardener out into the plastic lid.
  3. Apply it with a paint brush. Make sure you get enough on so that it completely soaks into the rotten wood.
  4. Leave it to dry for two hours.
  5. Scrub with a wire brush to get rid of any excess hardener.


Once you’ve used the hardener, you can focus on repairing the wood and filling any holes or cracks with Ronseal wood filler.


Clean your tools with white spirit.

Technical specification

Usage Any rotten interior or exterior wood
Dry time Two hours
Number of coats One
Colours Clear
Finish Clear
Durability Soaks deep into rotten wood to strengthen it
Application Brush
Size 250ml, 500ml
VOC Very high

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High Performance Wet Rot Wood Hardener
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