A reciprocating slat conveyor includes a plurality of laterally and substantially parallel longitudinal trough-like subdecks and a plurality of longitudinal slats adjacent to and parallel to each other. The slats are in a sliding relationship with a pair of adjacent subdecks and cover the longitudinal space between the pair of adjacent subdecks. The subdecks longitudinally support two adjacent slats at or near a slat longitudinal side edge. The subdecks conduct the movement of the slats, preferably without distinct bearing elements therebetween. Some preferred embodiments include raised double-seal system.