Wash. Rev. Code § 19.27.120
(1) Repairs, alterations, and additions necessary for the preservation, restoration, rehabilitation, strengthening, or continued use of a building or structure may be made without conformance to all of the requirements of the codes adopted under RCW 19.27.031, when authorized by the appropriate building official under the rules adopted under subsection (2) of this section, provided:
(a) The building or structure:
[ 1985 c 360 s 13; 1975-'76 2nd ex.s. c 11 s 1.]