Is Liquid Rubber Waterproof Sealant environmentally friendly? Yes, it is a water based product containing no solvents or VOC's (volatile organic compounds). Related articles How do I cover gaps and cracks? The black surface turns brown when wet? Is Liquid Rubber Waterproof Sealant safe for drinking water? Can I build my final membrane all at once? Can Waterproof Sealant be put on tarred surfaces? Comments 0 comments Please sign in to leave a comment.