Ronseal Wet Rot Wood Hardner - 500ml or 250ml

High Performance Wet Rot Wood Hardener


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

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