If you are fortunate enough to be involved with an essential building (hospital, police / fire station, communication facility), you have no doubt considered the ramification of the next major storm. That storm could take the form of a hurricane, tornado, hailstorm, wind event or other "Act of God." Assuming that the building will still be standing, will the operational effectiveness of the building be significantly impacted if the roofing system fails to remain watertight? After most significant storms, roofing systems fail because one or both of the following occurs:

The roof is displaced by wind.

Hail or collateral materials damage the roof.

So what can we do to minimize damage and safeguard operations? In three words . . . attachment, redundancy and protection.

First the roof system must be adequately attached so that it is not displaced by winds. This could require attachment in excess of normal building code or insurance standards. Without adequate attachment, roof system durability is inconsequential. This degree of securement may require additional mechanical attachment or the use of specialized adhesives to secure the roof to the building substrate. It is imperative that the roofing system remains attached if any hope for a watertight system is to be realized. Attachment through the use of pavers or ballast may cause more problems than it solves if the pavers or ballast become wind borne projectiles. If pavers or ballast are used they must be strapped together to create a unified front against wind uplift forces.

A sustainable roof system must be redundant. If the worst happens and part of the roof is damaged or becomes displaced, watertight integrity must prevail. We normally consider roofing system redundancy to be 3 or 4 plies of roofing felt in lieu of a single-ply membrane system. In the case of essential buildings, this is not adequate. The 3 or 4 plies of felt are still only one membrane and can be punctured or displaced just about as easily as a single-ply membrane. Redundancy in this case generally refers to a separate membrane installed directly over the roof deck and protected by the primary or top roofing system.

The importance and necessity of protecting the primary or top roofing system depends on the anticipated storm and the possibility of collateral damage. For example, if the building is isolated and the possibility of collateral damage is minimal, a substantial roof membrane may be sufficient protection. However, if the possibility exists that adjacent buildings, trees or even rooftop equipment may become air borne projectiles, then additional membrane protection may be required. Adequate protection may require the use of concrete pavers that are securely strapped together and restrained.

A well designed and installed roofing system emphasizing the principals of attachment, redundancy and protection should provide an essential building with the fortification necessary to survive the next storm and maintain life saving operations.