At the reconstruction works on historical buildings, considerable financial means are spent. Therefore, it is desirable to assess the durability of applied materials in the particular conditions of a specific building. This cannot be done effectively without the knowledge of their hygric and thermal properties which can be used as input parameters of computational models. In this paper, hygric and thermal properties of several types of materials which can be used as interior thermal insulation layers in reconstructions of historical buildings on Czech territory, among them calcium silicate, hydrophilic mineral wool, and sheep wool, are investigated. Experimental results show that all analyzed materials can be considered as suitable for interior thermal insulation systems of historical building envelopes, in general. Their hygrothermal performance in specific applications should though be verified using computational simulations, taking into account the complex character of some historical construction systems.