R502.1Revise Subsection R502.1 by replacing the third and fourth sentence as follows:An addition shall be deemed to comply with this code where the addition alone complies, where the existing building and addition comply with this code as a single building, or where the building with the addition achieves a certified HERS rating in accordance with Table R406.5. Additions shall be in accordance with Section R502.1.1, R502.2 or R502.3.
R502.1.1 Add Subsection R502.1.1 as follows:
R502.1.1Large Additions. Additions to a dwelling unit exceeding 1,000 sq. ft. or exceeding 100% of the existing conditioned floor area, shall require the dwelling unit to comply with the maximum HERS ratings for alterations, additions or change of use shown in TABLE R406.5.R502.2Delete the Exceptions in Subsection R502.2.R502.3.1Replace the Exception in Subsection R502.3.1 as follows:Exception: New envelope assemblies in additions of less than 1,000 sq. ft. are exempt from the requirements of Section R402.4.1.2.
R503.1.5 Add new subsection as follows:
R503.1.5Level 3 Alterations or Change of Use. Alterations that meet the IEBC definition for Level 3 Alteration or the IRC definition for Extensive Alteration, exceeding 1,000 sq ft or exceeding 100% of the existing conditioned floor area, shall require the dwelling unit to comply with the maximum HERS ratings for alterations, additions or change of use shown in Table R406.5.R505.1Delete the Exception in Section R505.1.Adopted by Mass Register Issue 1485, eff. 12/23/2022.