We researched several manufacturers and asked them "Is there an expiry date on your insulation?" Their response came to us as no surprise. "What an odd question. Why are you asking me this?" As a matter of fact, there is no expiry date on insulation since it's an inert product. As long as it stays dry, it will last forever. Unfortunately there are some in the roofing industry who claim otherwise and benefit from this misunderstanding. If you won't take our word for it, call up a few insulation manufacturers and ask them yourself. Many clients want the best possible job and request their entire roof be removed. If you're one of these clients, consider this. By upgrading your roof as well as the insulation, it will save you substantial energy costs. If you choose to remove the existing roof, you're consuming energy and money in the process and contributing to environmental damage by sending it to a landfill for no good reason. In some instances, insulation such as Phenolic Foam can produce phosphoric acid when it comes in contact with humidity. This will eat away at the structural elements of the roof deck over time and must be removed. On the average, 5% of roofs utilize this kind of insulation and we encounter at least one or two of them a year. For the other 95%, there's no technical reason to remove insulation from a building.