IPC 2013 : E04B 7/24 : the slabs being collapsible, e.g. for transport.

IPC2013 > E > E04 > E04B > E04B 7/00 > E04B 7/24[2] > the slabs being collapsible, e.g. for transport.
Notes[t] E01 - E06: BUILDING
E SECTION E — FIXED CONSTRUCTIONS.
E04 BUILDING.
E04B GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS (border constructions of openings in walls, floors, or ceilings E06B 1/00).
E04B 7/00 Roofs; Roof construction with regard to insulation (structures for roofs as well as for floors E04B 5/00; ceilings E04B 9/00; greenhouses A01G 9/14; large containers having floating covers B65D 88/34; roof trusses, truss-like structures, joists E04C 3/02; roof coverings E04D).
E04B 7/24 · · the slabs being collapsible, e.g. for transport.