Despite the fact that the building code requires the ice and water shield to overlap the drip edge, some drip edge manufacturers recommend installing the drip edge over the ice and water shield. This reversal provides superior protection in the event of an ice dam. It also allows for easier maintenance by exposing only the overlapping section of drip edge. The drip edge should be installed so that it meets the building code requirements. If it does not, your local building authority may require you to replace or modify the drip edge in a way that satisfies their needs. In conclusion, the drip edge should always be installed so that it covers the ice and water shield. This will provide the best protection against potential flooding caused by ice dams and other water intrusion issues.