roof deck

Noun

 * 1) The flat layer of construction materials to which the weather impervious layers are attached to a form a roof. It is known as the "roof deck", and they may be either level (for a "flat" rooftop) or sloped.
 * 2) An upper deck of a ship that provides shelter for another deck underneath.
 * 1) An upper deck of a ship that provides shelter for another deck underneath.