The provisions of Section C502 of IECC-CE are adopted by reference with the following modifications:
1. Revise Section C502.1 to read:
"Additions to an existing building shall conform to the provisions of this code as those provisions relate to new construction without requiring the unaltered portion of the existing building to comply with this code. Additions shall not create an unsafe or hazardous condition or overload existing building systems. An addition shall be deemed to comply with this code if the addition alone complies, if the existing building and addition comply with this code as a single building or if the building with the addition will use no more energy than the existing building."
2. Revise Section C502.2 by replacing "nonconditioned" with "unconditioned."
3. Revise exception 2 to Section C502.2 to read:
"Where the total building performance option in Section C407 is used to comply with this section, the annual energy cost of the proposed design shall be not greater than 110 percent of the annual energy cost otherwise allowed by Section C407.2."
4. Revise Section C502.3.1 to read:
"Additions shall comply with the following:
1. Where an addition has vertical fenestration that results in a total building vertical fenestration area less than or equal to that allowed by Section C402.4.1, the addition shall comply with Section C402.1.5, C402.4.3 or C407.
2. Where an addition has vertical fenestration that results in a total building vertical fenestration area greater than that allowed by Section C402.4.1, the vertical fenestration shall comply with Section C402.4.1.1 for the addition only.
3. Where an addition has a vertical fenestration area greater than that allowed by Section C402.4.1, the vertical fenestration shall comply with Section C402.4.1.1 for the addition only.
4. Where an addition has vertical fenestration that results in a total building vertical fenestration area exceeding that allowed by Section C402.4.1.1, the addition shall comply with Section C402.1.5 or C407."
5. Revise Section C502.3.2 to read:
"C502.3.2 Skylight area.
Additions shall comply with the following:
1. Where an addition has a skylight fenestration area that results in a total building skylight fenestration area less than or equal to that allowed by Section C402.4.1, the addition shall comply with Section C402.1.5 or C407.
2. Where an addition has a skylight fenestration area that results in a total building skylight fenestration area greater than allowed by Section C402.4.1, the skylights shall comply with Section C402.4.1.2 for the addition only.
3. Where an addition has a skylight fenestration area greater than that allowed by Section C402.4.1, the skylights shall comply with Section C402.4.1.2 for the addition only.
4. Where an addition has a skylight fenestration area that results in a total building skylight fenestration area exceeding that allowed by Section C402.4.1.2, the addition shall comply with Section C402.1.5 or C407."
6. Revise Section C502.3.3 by replacing "building" with "existing building’s."