To assist with the correct design of buildings, many computational models have been developed to assess the transient heat, air, and moisture (HAM) transfer within building walls. Validation of these computational models is essential to gain confidence in the codes. This paper provides datasets for validating 1-D heat and mass transfer models step by step, gradually increasing the complexity of a multilayer wall with hygroscopic components. The experiments were performed using a double climatic chamber. The climatic conditions on either side of the wall progress from the simplest boundary conditions (isothermal) to more complex ones with oscillations that mimic the mid-season period. To assess the hygrothermal response of the tested walls under such climatic conditions, the conditions of ambient air and the temperature and humidity profiles within the wall thickness are monitored during the test. This paper gives some detailed information on the chamber design, the instrumentation, the materials, and the climatic conditions so that other researchers can use the collected data for validation of their models or to build future test facilities. The results obtained with the test facility highlight the coupling that exists between heat and mass transfers across multilayer walls using hygroscopic components. The heat release by moisture adsorption is observed in the temperatures profiles. During the mid-season period, the results show the differences of the phase shift and the amplitude attenuation of the temperature and the water vapour pressure across the wall thickness.