The goal of tapered roof insulation systems is to reduce or eliminate the amount of ponding/standing water on the finished membrane when the roof deck does not provide adequate slope. Draining the water in a timely and efficient manner minimizes the adverse effects that ponding/standing water can have on completed roof membranes. A properly designed tapered roof insulation system, not only provides the positive drainage needed but also helps extend the life of the roof membrane, and provides thermal value as well thus reducing the heating and cooling expenses of the building owner.