What temperature can I apply Liquid Rubber Waterproof Sealant? Liquid Rubber Waterproof Sealant should be applied above 5°C (41°F). Avoid hot, direct sunlight applications. Related articles Can I build my final membrane all at once? How should I prepare the surface before applying Waterproof Sealant? What should I use to clean up? How come it feels tacky? Is it cured? How do I cover gaps and cracks? Comments 0 comments Please sign in to leave a comment.