Nothing in the Building Construction Act shall be construed to authorize any state agency or political subdivision to regulate the construction of farm buildings or other buildings or structures when such regulation is otherwise prohibited by law. Nothing in the act shall be construed to authorize any state agency or political subdivision to have any authority either to establish or to continue in effect, with respect to any manufactured home built pursuant to the National Manufactured Housing Construction and Safety Standards Act, 42 U.S.C. § 5401 to 5426, any standard regarding construction or safety which is not identical to standards promulgated by the National Manufactured Housing Construction and Safety Standards Act, 42 U.S.C. § 5401 to 5426, and the regulations promulgated by the United States Department of Housing and Urban Development under the federal law when there is in effect a standard of the National Manufactured Housing Construction and Safety Standards Act, 42 U.S.C. § 5401 to 5426, or the regulations applicable to the same aspect of performance of such manufactured home.