This home doesn't actually have a deck above, the railing was to match the railing on an existing flat roof on the other side of the house. When we do flat roofs with a terrace/deck above we typically use one of 2 products: Wausau tile pavers http://www.wausautile.com/paving/architecturalPavers.cfm installed on a pedestal system, this allows the surface water to filter through and drain as it normally would. The structure below will need to be sized to handle the additional weight of the paver material as they are concrete.

thanks so much!! You said one of two products...are they both Wausau tile paver products?