Through five experiments, a combination of I-joists with different flange sizes and different combustible insulation types (wood fibre, cellulose and phenolic foam) were exposed to the standard fire curve (ISO 834) in a medium-scale furnace. the aim was to better understand the charring mechanisms of the I-joist when protected with a combustible insulation. Thermocouples were embedded into and outside of the flanges and used to determine the charring rate of the I-joist and the recession rate for the insulation. After exposure, the final char depth and the remaining cross-section were measured. Raw data of temperature measurements are provided here. More information is given in the published paper: "Experimental Study of the Charring of I-Joists and Recession of Combustible Insulation in Light Timber Frame Assemblies with Comparison to Eurocode 5"