C503.3.1 Roof replacement. Roof replacements shall comply with Section C402.1.3, C402.1.4, C402.1.5 or C407 where the existing roof assembly is part of the building thermal envelope and contains insulation entirely above the roof deck.
Code Interpretation:
Existing buildings requirements are sprinkled throughout the I-Codes; for roofing replacements it is necessary to look at the IBC (International Building Code), the IEBC (International Existing Building Code), and the IECC (International Energy Conservation Code). The IBC addresses weather protection, fire resistance, and structural performance requirements, while the IEBC includes provisions for retrofit upgrades under certain conditions.