How your house is built and its foundation type determine what type of retrofit your house needs. Houses with a raised concrete perimeter foundation that lack sill plate anchors and/or cripple wall bracing may follow existing state building code (CEBC, Appendix Chapter A3) or standard plan sets, which also provide step-by-step directions.  The following types of houses may require an engineer to design a retrofit: Soft-story row houses Houses on hillsides Houses with living space over the garage Post and pier foundation houses