Samples from medieval wooden doors in Dalarna, Sweden were sent by the County Administrative Board of Dalarna to the Heritage Laboratory at the Swedish National Heritage Board for analysis. The research question was to determine whether the doors are coated with tar or another substance. The analysis report compiles data from the following analytical techniques is included: 1. X-ray fluorescence spectroscopy (XRF); 2. Fourier transform infrared spectroscopy (FTIR); 3. visible and UV light optical microscopy. Project code RAÄ-2025-1685. The final report from the County Administrative Board of Dalarna is also included and compiles information about the original project, written before analysis at the Heritage Laboratory occured. The data for the analysis report and instrument reports containing analysis parameters can be found at: 10.5281/zenodo.18430797.