This thesis explores the narrow spaces between closely built houses in the over 300-year-old wooden town center of Mariestad, Sweden, and their potential as time capsules and sources of knowledge in cultural-historical building investigations. By interpreting well-preserved carpentry work on a facade in one of these spaces, the study aims to provide an example of how these preserved spaces can serve as a source of knowledge and understanding of craftsmanship and the history of the place. The thesis also addresses the municipality of Mariestad's work with cultural heritage, as well as maps out more of these potentially interesting interstitial spaces. Old Swedish wooden towns possess a high degree of uniqueness both nationally and internationally; nevertheless, they are subjected to relatively significant threats of demolitions and substantial changes, often in the form of many smaller restorations or changes over a long period of time. The focus of the case study is a window from the 16th or 17th century and the facade's old, hand planed wooden cladding.