Between 2021 and 2024, a survey of medieval roof structures in churches within the Diocese of Växjö was conducted. The primary aim of the project was to enhance and deepen the understanding of these medieval roof structures and their history. A secondary aim was to create an inventory of preserved medieval roof structures in the Växjö Diocese. The preserved medieval roof structures of Sweden represent a unique contribution to the European heritage of medieval architecture. These physical artefacts are crucial for understanding the society and culture of that period, given the scarcity of written sources. The survey methodology included archival and literature studies to select the churches for investigation. Field studies involved examining two churches per day, with results continuously documented in a digital database. Simple survey drawings were made when necessary. Existing dendrochronological sampled timbers were reviewed and for certain churches also the samples were reanalysed. In some churches additional sampling for dendroanalysis was taken. During the survey, 89 churches and their roof structures were investigated. In 59 of these, 96 completely or partially preserved medieval roof structures were found. Among these, 35 early medieval roof structures (1100–1350) are well-preserved, and 29 late medieval roof structures (1350–1550) are well-preserved. The findings are documented in a report and a catalogue of the surveyed roof structures. Several of the documented medieval structures were previously unknown. The results provide a foundation for the long-term and sustainable management of this important cultural heritage.