Penetrates deep and hardens decaying wood to give a solid base for wood filling. Suitable for interior and exterior use. This no-fuss wet rot wood hardener from Ronseal gives interior and exterior wood a new lease of life. Harden wet wood and stop nasty rot from spreading, whether it's your garden furniture or a water-damaged window frame. The fluid seeps deep into the wood and sets rock hard, reinforcing decaying parts and providing a solid base for filling. The hardener dries quickly with a clear finish. The lid doubles as a container, so everything you need is included. A little goes a long way, and one tin should see you through plenty of jobs around the house. High performance wet rot wood hardener, hardens decaying wood for a solid base when wood filling, penetrates deep, interior and exterior use, only one coat required, quick drying - dries in 2 hours, sets rock hard with a clear finish, 500ml.