Abstract: A method for improving water transport and reducing shrinkage stress in membrane humidifying devices, and membrane humidifying devices and systems employing such devices that achieve enhanced and stable humidification performance, are disclosed. The inventive membrane humidifying device is made up of at least one membrane cell and means for introducing water into the cell(s). The membrane cell(s) includes at least one sheet of a hydrophilic membrane and at least one rigid screen, positioned adjacent to at least one membrane sheet. The cell(s) is assembled when the membrane sheet(s) is in a dry, contracted state and the assembled cell(s) is then exposed to an elevated temperature/vacuum treatment. As a result, the surfaces of the membrane sheet(s) permanently conform to the contours of an adjacent rigid screen.