This dataset contains measurement from a hotbox coldbox experiment involving a solid wall wooden beam end connection at KU Leuven. The focus of this study has been on the impact of an air gap between finishing and beam end, involving different internal insulation systems. Further, it includes photo documentation of construction and installation of sensors. Further details to be found in RIBuild deliverable D3.1. Overview of data files to be found in 'RIBuild data WP3_KUL Test stand' as part of this dataset. Further data on hotbox coldbox experiments can be found in the dataset 'RIBuild: Hotbox coldbox experiment with solid wall in combination with wooden beam ends at TU Dresden' (https://zenodo.org/deposit/3904836). Data from measurements on solid wall wooden beam end connections at an outdoor test unit can be found in the dataset 'RIBuild: Outdoor test stand with solid wall in combination with wooden beam ends at DTU' (https://zenodo.org/deposit/3903524).