2012 International Residential Code
R703.8 Flashing
Approved corrosion-resistant flashing shall be applied shingle-fashion in a manner to prevent entry of water into wall cavity or penetration of water into the building structural framing components.... more

2012 IRC, Roof Assemblies
R903.2 Flashing. Flashing shall be installed in a manner that prevents moisture entering the wall and roof through joints in copings, through moisture permeable materials, and at intersections with parapet walls and other penetrations through the roof plane.
R903.2.1 Locations....more