Insulated shipping container and method of making

A thermally insulating shipping container, comprising:

• an outer container that is a box formed of paper and having a floor and a plurality of sidewalls;
• an inner container that is a box formed of paper and having a floor and a plurality sidewalls, a space interior to the plurality of sidewalls of the inner container defining an inner cavity to hold a product for shipping in the shipping container;
• a recyclable or compostable thermal insulation material formed primarily of plant fiber disposed between the sidewalls of the inner container and the sidewalls of the outer container;
• and
• a barrier formed of paper positioned to cover at least a portion of a top surface of the thermal insulation material between the sidewalls of the inner container and the sidewalls of the outer container, the barrier comprising
• a horizontal collar positioned substantially co-planar with and surrounding an upper rim of the plurality of sidewalls of the inner container and below an upper rim of the plurality of sidewalls of the outer container,
• a first plurality of overhanging sections extending from a rectangular inner edge of the collar, each overhanging section of the first plurality of overhanging sections folded downwardly to extend partially but not entirely along a height of a corresponding sidewall of the inner container, and
• a second plurality of overhanging sections extending from a rectangular outer edge of the collar.