Shelf Life Generally you can store the products 1-2 years unopened in warm place. Related articles What product do you recommend for a 20x20 flat roof ( pitched 4 1/2" over 20' ) which will be planted. AKA green roof? How should I prepare the surface before applying Waterproof Sealant? Can any of your products be used to cover a pond lining? Storing Opened Material Comments 0 comments Please sign in to leave a comment.