Encourages the use and reuse of existing buildings. This code covers repair, alteration, addition and change of occupancy for existing buildings and historic buildings, while achieving appropriate levels of safety without requiring full compliance with the new construction requirements contained in the other I-Codes. Key changes include:

• Section 410 Accessibility has been relocated to a new Section 305. Chapters 4, 5, 6, 13 and 14 have been relocated resulting in a reorganization and new chapter numbering.
• Requirements for live loads from Chapters 4 and 8 have been combined and placed in Chapter 3 to apply for all compliance methods.
• Structural components damaged by snow events must be repaired assuming snow loads for new buildings from the IBC.
• A new exception is added for loading of existing structural elements next to an addition in buildings designed using the IRC.
• When a work area includes more than half the building in an alteration, wall anchors must be installed at the roof line along reinforced concrete and masonry walls.
• Buildings undergoing a change of occupancy shall have live, snow, wind and seismic loads checked. Design loads are based on IBC-level forces.
• When a change of occupancy occurs placing a building in a higher risk category, the seismic loads on the building must be evaluated using IBC-level forces. Access to the building must be maintained when passing through or near other buildings and structures.
• Where storm shelters are required based on IBC and ICC 500 for Group E Occupancies, any addition to such existing occupancies where the occupant load of the addition is 50 or more will trigger the construction of a storm shelter.
• Carbon Monoxide provisions have been added in the Prescriptive Method Additions, Alterations Level 2 Additions, and in Additions for I-1, I-2, I-4 and R Occupancies.
• Emergency Escape and Rescue Opening provisions related to being operational have been added to Prescriptive Compliance Method and Alterations Level 1.
• Single exit buildings and spaces under Alteration Levels 2 and 3 have been modified to be more consistent with the IBC.
• The Alterations Level 2 requirement that water for automatic fire sprinkler system be available at the floor of alteration without the need for a fire pump has been moved to Chapter 9 for Alterations Level 3 and the fire pump criterion was deleted