Extensible attic staircase hinged ceiling panel - has heat insulating layer between flat outside load bearing layers

摘要

The staircase, as fitted in the top storey of a house below the floor of the attic or roof space, is exensibly and retractably attached to a stairs panel with one side hinged to a frame built into the ceiling. The panel (11) is made up from two flat external load bearing layers (16) and an internal heat-insulating layer (17). The former may be chipboard panels, and the latter made of hard polyurethane foam with heat conductivity of 0.030 kcal/mh deg.C. The outside layers are pref. 10 mm thick. and the inside one 30 mm. Heat loss through the ceiling hatch is reduced.