Bostik Water Seal is a high-performance waterproofer for trade use, that penetrates deep below the surface to provide a water resistant barrier on porous exterior surfaces. It is suitable for concrete, brick, stone, slate, terracotta, render and timber.

The surface remains permeable to water vapour, allowing it to ‘breathe’, preventing water being trapped. Water Seal is transparent and should not alter the appearance of the treated surface. Some surfaces may darken very slightly, so always carry out a test on a small area before full application. Water Seal also helps to prevent condensation, efflorescence and frost damage.