Interior Detail as an Artefact, Reflecting Cultural Value and Architectural Style

The purpose of this study is to examine the importance of architectural details and artefacts as cultural markers within the interior spaces of adaptively reused heritage buildings in Sofia’s historic urban centre. A comparative study was performed on three significant early twentieth-century residential buildings: the house linked to the former ‘Excelsior’/‘Asen Zlatarov’ cinema complex at Blvd ‘Christo Botev’ N85, the former residence at Blvd ‘Christo Botev’ N75, and the building at Blvd ‘Stamboliyski’ N36—the latter two have both been transformed into hotels. The research employs an interdisciplinary methodology combining archival research, field surveys, photographic documentation, 3D laser scanning, and comparative stylistic analysis. The study’s principal contribution is the development of a transferable analytical framework for classifying interior details by function (constructive or decorative), location (enclosing surfaces, fixed furnishings, vertical circulation), and material—a framework not previously applied to this building stock in the Bulgarian context. The findings confirm that authentic interior details—including stair railings, flooring patterns, gypsum cornices, ornamental plasterwork, heating appliances, and joinery—function as reliable cultural artefacts and markers of historical period and stylistic identity. These details serve as evidence for dating, authenticating, and analysing the evolution of architectural style elements. Preserving and integrating these elements into adapted interiors strengthens architectural identity and supports the sustainable reuse of cultural heritage for contemporary purposes.