In areas where there has been a history of ice forming along the eaves causing a backup of water, an ice barrier that consists of at least two layers of underlayment cemented together or of a self-adhering polymer modified bitumen sheet shall be used in lieu of normal underlayment and extend from the lowest edges of the roof surfaces to the point at least 24 inches inside the exterior wall line of the building.
This code implies that ice and water shield—eaves flashing—is required for installation on all heated, steep-slope structures (exception is unheated structures) in colder climates. The eaves flashing shall be installed from the end of the deck to a minimum of 24 inches up the slope.
Eaves flashing is required to prevent ice formation at the eaves and gutter to back up beneath the roof covering.
All of the steep-slope material manufacturers provide eaves flashings with their systems. Application shall be in compliance with the manufacturers requirements. Attachment methods shall be in compliance with local codes.