Toupret wood hardener is a colourless, moisture cured liquid, used following the removal of rotten and decaying interior or exterior timber due to dampness. Wood hardener is a thin liquid which penetrates residual wood fibers in soft and previously decaying timber, binding and strengthening them together. It cures and hardens within 24 hours, providing a sound, hard consolidated surface which is ready for filling. Formulated using a more expensive moisture cured binder - do not apply directly to wet substrates.