A contemporary interpretation of the historic wash house as a place for communication could be an interactive video installation.
The public of Differdange could send digital messages (e.g. via Twitter) that would be processed and them come flowing out of the old wash house in a text stream beamed on the Rue Victor Hugo.
Also voice recordings could be sent to the Waschuber that would then be hearable as a babilonic murmur that comes out of the washhouse and remembers the times when the wash women used to work and chat in the historic halls.
An advantage of the concept is that the historic building itsself will not be physically touched by the installation and that it creates a feeling of water – which is THE central element of a was house – without bringing any moist to the old walls.