•Radiocarbon dating of two consecutive settlements, Chalcolithic, present-day Bulgaria.•Short-lived remains / grains versus timber; radiocarbon data limits and correlations.•Generating of sub-sample populations; their role in assessing absolute chronology. The main aim of the recent research of the Prehistoric Tell at the village of Ivanovo, Shumen District is to clarify the complex stratigraphy and cultural history of the site, one of the 83 Prehistoric settlements unearthed in this region of present-day Bulgaria. To solve the particular situation of two horizons, we used conventional research, such as observations on the stratigraphy and the main characteristics of the pottery, and radiocarbon dating method. The paper focuses on radiocarbon dating of two consecutively existing superimposed buildings – Building 1 from horizon VIII (1/VIII) and Building 2 from horizon VII (2/VII). Even if all samples were initially characterized by the nature of archaeological material and by their calibrated ages, the laboratory strategy finally chose only a few data for refining relative chronology and gain a better understanding of the stratigraphy. The use of the OxCal program functions allowed the selection and combination of reliable radiocarbon data and the establishment of an objective criteria demonstrating the chronological succession of the two constructions and why they cannot be considered contemporary.