A structure insulated for example by expanded polyurethane such as a refrigerator cabinet or freezer cabinet, comprising at least two compartments having inner walls and outer walls separated from each other by an interspace having opposing ends, the insulating material injected into said structure in any known manner surrounding said compartments on all sides except an access side, the interspace having at least one separator member at one of said opposing ends of said interspace there being provided at least one separator member arranged to separate, during its injection into the structure, the insulating material directed around the compartments from that directed into the interspace, wherein said separator member comprises at least two portions, said portion connected together having first and second ends, at at least one of said ends, said portions being able to withdraw from each other following the injection of the insulating material into the interspace.