The black surface turns brown when wet? This is normal on the surface, the waterproofing is not affected. Related articles What if I don't want black as my final color? Is Liquid Rubber Waterproof Sealant safe for drinking water? What if I see blisters? Will sun have an effect on the Liquid Rubber Waterproof Sealant? How should I prepare the surface before applying Waterproof Sealant? Comments 0 comments Please sign in to leave a comment.