Sandwich panel developed and marketed in mid-20th Century by Wunderlich Ltd as Insulabestos, an inner core of insulating material surfaced with a Durabestos AC sheet on both faces.

The insulating material has not been identified but may be Masonite mixed with other materials. Wunderlich advertising only details the core as insulating fibre.

Marketed for ceilings, walls, doors and partitions in dwellings, shops, factories and offices as a sound retardant.

Other sandwich panel systems with AC sheeting were used in modular (kit) homes in late 1970s-early 1980s, incorporating a core of polystyrene. These panels may have been independently used in other structures.

See Modular homes.