(1) A city or county planning under RCW 36.70A.040 must allow for the following:
(a) For retrofits of existing buildings to be used for residential housing:
(i) The portion of exterior wall assemblies that includes insulation must be allowed to project up to an additional eight inches into the setbacks on all sides;
(ii) The building must be allowed to exceed the maximum allowable roof height by eight inches to accommodate additional insulation; and
(iii) Gross floor area must be measured from the interior face of the exterior walls, which includes drywall, as typically depicted on the architectural floor plans.
(b) For existing nonconforming buildings already projecting into setbacks, the portion of exterior wall assemblies that include insulation must be allowed to project up to an additional eight inches into the setbacks on all sides if the building is to be used for residential housing.
(2) Nothing in this section prohibits a city or county from applying the requirements of the state building code or requires a city or county to allow a setback of less than 36 inches between residential dwelling units.
[ 2025 c 139 s 1.]