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 What should I use to clean up? How should I prepare the surface before applying Waterproof Sealant? Can I build my final membrane all at once? Does the product have a detrimental impact to fish or aquatic plants? What if I see blisters? Comments 0 comments Please sign in to leave a comment.