Impact and/or sound deadening hydronic sub-flooring panel and related system and method

A sub-flooring panel for use with a heating element comprising:

• a first solid base body having a first recessed formation adapted to receive the heating element, the first recessed formation having:
• a bottom portion having a semi-circular cross-section with a first diameter;
• and opposing step formations, each step formation having a rise and a run, the rises of the opposing step formations separated by a second distance greater than the first diameter;
• a cap member having flat side portions, each flat side portion supported on a respective run of the opposing step formations, the cap member configured to cover the heating element, the cap member having a second recessed formation adapted to receive a portion of the heating element;
• and
• at least one thermally-conductive liner configured for contact with both the heating element and the first solid base body, the liner having at least a first portion and a second portion, the first portion positioned between the heating element and the second recessed formation of the cap member, the first portion of the liner generally conforming to the second recessed formation of the cap member, the second portion of the liner positioned between each of the flat side portion and its respective opposite step formation,
• wherein an upper portion of the first recessed formation configured to receive the cap member has a greater width and the cap member has a smaller width configured to provide a lateral space gap.