## 5 Conclusions  
This paper assesses various internal wall assemblies by comparing their moisture buffer values (MBVs). Because there is no single globally agreed method for determining MBVs, a modified Nordtest protocol was used in this study. This step response method is not representative of real indoor RH variation, but is a simplified way to present the effect of different internal and external layers on the MBV of the wall assembly. From a hygric point of view, all wall assemblies had a moisture-buffering capacity corresponding to the Nordtest'moderate' category.  
From the results, the MBV of Assembly A was slightly higher than that of Assembly B. Assembly A and Assembly B differed only in the type of internal insulation used. Both insulation materials had low and comparable vapour diffusion resistance factors \(\mu\), but the slope of the sorption isotherm was higher for the Pavaflex fibreboards used in Assembly B than for the mineral wool ECOSE used in Assembly A. Thus, the higher the adsorption curve and moisture capacity \(\xi\), the higher the moisture accumulation in the material.  
In turn, the higher MBV of Assembly C than of Assembly D indicates that, in the case of Assembly D, the internal layer of Pavaflex board, despite the higher sorption isotherm, was not fully active in the process of moisture buffering. The additional external layers significantly reduced the MBV capacity of the internal layer and changed the overall performance of the whole wall assembly.  
The comparison of the MBVs between selected materials (wood fibreboard--Pavaflex, Pavaboard and gypsum fibreboard) and the MBVs of the assemblies showed that the MBVs of individual materials are higher. This can partially be attributed to the vapour diffusion resistance factor of the individual materials, which, combined with the effect of thickness, could decrease the moisture-buffering capacity  
Figure 10: The correlations between measured and simulated results: (**a**) Assembly A; (**b**) Assembly B; (**c**) Assembly C; (**d**) Assembly D.  
of the internal layer, especially the flexible wood fibreboard (Pavaflex) in Assembly D. This implies that the internal layers were not fully participating in the moisture buffering of assemblies.  
In addition, the comparison of the moisture penetration depth values for individual layers of the tested assemblies confirmed that wall assemblies made of layers with materials characterized by a lower value of penetration depth reach steady state more slowly. Wall assemblies finished with earthen plaster with straw showed a higher MBV than assemblies covered with gypsum board, despite the higher sorption isotherm of gypsum board compared to clay plaster and the comparable vapour diffusion coefficient of resistance. The thickness of the plaster with straw was smaller than the penetration depth calculated for it. It can therefore be concluded that if the penetration depth value \(\mathrm{d}_{\mathrm{P}}\) of the outer layer is greater than its thickness, vapour penetrates through this layer and reaches into the deeper layer.  
The present research confirmed the results of previous studies that suggested that one layer can have a significant effect on the response of another layer, and therefore the hygric behaviour of whole assemblies cannot be assessed in a simple way.  
Since the hygric performance of multilayer structures with different types of coating and hygroscopic layers is difficult to predict, simulation seems to be a good tool for studying hygothermal behaviour. The WUFI Pro tool, as a widely available and easy-to-use computer tool, was chosen to perform the simulations. Despite the discrepancies between the measured and simulated values, it can be used as a simplified method for helping designers make decisions about which materials to choose to improve the moisture-buffering effect.  
The author would like to thank all other members of the research team for their help in testing the hygrothermal properties of materials.  
The author declares no conflict of interest.