A subfloor component includes an insulating foam panel having first and second opposing faces and a plurality of intersecting grooves to define, in cross-section, a plurality of pedestals having walls that extend into the panel from the first face toward the second face. The subfloor component also includes a moisture-resistant film attached to the first face of the panel and that conforms to the pedestals, and a hardboard layer on the second face of the panel. A method of manufacturing subfloor components is also disclosed.