A Joist Plate System is a sister interlocking system, using joist plate component and top shim components. This allows easy installation of concrete pavers, natural gauged stone, and other architectural slabs over wood joists. This system easily adapts to new and old decks, virtually ending the drudgery of maintaining a wood slat deck.
4x6's should be used in new construction, or sistering 2x4's with 2x4's should provide a working under-layment. If deck is suspended, engineering may be required to support the weight. Consult a specialist regarding load and structural requirements.