The present invention provides a foldable enclosure intending as a building or portion of a building that may be transported to a desired site in a folded configuration and then expanded into its intended form. A colored dispersion liquid in which a dispersoid is dispersed in a dispersion medium is suitably used as the liquid 42. The constraining layer has a greater stiffness and higher modulus of dynamic shearing elasticity than the viscoelastic damper layer, and is molded from a high density filler and a moldable compound that is immiscible with the viscoelastic damper layer to provide a discrete interface between the constraining layer and the viscoelastic damper layer.