Abstract: A deck unit is disclosed to form a deck system for a roof or floor that is capable of supporting a heavier load and/or spanning greater distances. The deck unit is a profiled, metal unit, that derives its greater load-bearing strength in part from its greater depth but provides flexibility in achieving the greater strength from the way the additional depth is obtained. In particular, a full length channel is attached to a hat-shaped profile. The channel adds strength both by increasing deck unit depth and by avoiding lengthening the webs on the hat-shaped profile. The channel increases design flexibility by allowing the designer to increase the strength of pre-existing decks by the addition of a channel of suitable metal thickness and size. It also provides a channel for conduit, cabling and wiring. The deck unit may be fluted or, by the addition of a liner panel to close the interior of hat-shaped profile, cellular. Sound absorbing materials can be installed in either a fluted or cellular deck unit.