The measurement of transport properties of these bricks has been described in detail previously [1]. Vapor diffusivity was measured by means of a cup test according to DIN standard 52-615 [14]. The relative humidity gradient for this test was between 3 % RH and 50 % RH. When the rate of mass increase of the cup containing the sample was linear, the slope was used to determine the material vapor diffusivity. Air permeability was measured on the same samples used in the vapor diffusivity test. The sample was sealed in the testing device and the air flow measured at a series of pressure steps. Knowing the flow rate and the pressure differential across the sample, the air permeability was easily calculated [1].