A method of manufacturing a non-disassembling partition assembly comprises providing a partition matrix made up of intersecting first and second slotted partitions. The partitions may be made by folding over a partition blank and securing a foam portion of the folded partition blank to itself. The foam may be heated before being cooled under pressure to secure opposed plies of the partition together. The partition assembly is held together by a floor parent welded to the intersecting partitions. The floor has a lower outer skin and a foam layer to which the partitions are parent welded.