(under subclass 2.11) Structure wherein the building structure or component comprises a member, often sheetlike in nature, which is shaped by the fluid it encloses and which, in turn, serves to shape or support one or more elements of a building that are being formed from material initially lacking a shape-retaining property, but which material subsequently undergoes a change of state and becomes relatively rigid.
(1) Note. Upon the change of state of the material, the member often becomes superfluous, and, in some instances, is removed.
