In plant engineering, all products are unique. Nevertheless, it should be possible to find and reuse as many repeat parts as possible. Existing search tools in PDM systems are not suitable for this purpose, since they are too uneconomical in terms of data maintenance in view of the small quantities of plant products, or they are originally designed for retrieving individual parts, but not building structures. This paper proposes the approach of performing repeated searches on the basis of similar building structures and combines concepts of fuzzy searches with the traversal of product structures for this purpose.