B deck, also called wide rib deck, is a 1.5″ deep metal roof deck with wide top flutes and ribs at 6″ on center. It is the most widely used roof deck in North America because it spans typical joist spacings efficiently and gives good support for rigid insulation. A composite version is also used for floors.

N deck is a 3″ deep roof deck with narrow ribs, typically at 8″ on center. Its extra depth gives it much higher stiffness than B deck, so it can span farther between joists or beams. It is a good choice for long-span roofs where wider joist spacing reduces the total number of joists and speeds up erection.

Roof deck is non-composite: it carries loads on its own and supports insulation and roofing. Composite floor deck has embossments that bond with the concrete, so once the slab cures the deck acts as its reinforcement and the deck and concrete work together as one structural element.

Both receive concrete, but form deck only acts as a permanent form: the slab needs its own reinforcement, such as welded wire mesh or rebar. Composite deck bonds with the concrete and provides the slab's positive reinforcement, which allows longer spans and thinner slabs.

Roof and composite deck are most commonly supplied in 22, 20, 18 and 16 gauge, where a lower number means thicker steel. The right gauge depends on the span between supports, the design loads and the diaphragm requirements set by the project engineer. Send us your drawings and we will confirm the gauge and profile.