Steel Roof Deck & Floor Deck

Steel roof deck and floor deck span joists and beams to carry the roof or the concrete slab. Roof deck and acoustic roof deck sit under membrane roofs, while composite floor deck and form deck take the pour on floors.

Steel Roof Deck

Galvanized steel deck that spans between open-web joists, purlins or beams and carries the insulation, membrane, snow and wind of a flat or low-slope roof. Fastened down and lapped sheet to sheet, it also ties the roof into one stiff diaphragm.

Acoustic Roof Deck

Roof deck with perforated webs and a glass-fibre acoustic batt in every rib. Sound from the room passes through the perforations into the batts and is absorbed, so an exposed deck ceiling reaches a noise reduction coefficient of about 0.70, while the roof above is built exactly as on a plain deck.

Composite Floor Deck

Galvanneal steel deck with embossed webs. During the pour it is the form, carrying the wet concrete and the crew with little or no shoring; once the concrete cures, the embossments lock the slab to the steel and the deck becomes the bottom reinforcement of a composite slab.

Form Deck

Shallow corrugated galvanized sheet that stays in place as a permanent form under a concrete slab or topping. It carries the wet concrete and the crew across short spans between joists or beams, so there is no formwork to build and strip. The deck is a form, not reinforcement.

More Products

Four decks, four jobs

All four are ribbed or corrugated steel sheet. What sits on top of them, and what the deck has to do once it is there, decides which one you need.

Deck	Carries	Profiles	Gauge
Steel roof deck	Insulation and membrane roof	1-1/2" × 6"; 3" × 6", 8", 12"	22 to 16
Acoustic roof deck	Roof, and absorbs room sound	Same as roof deck, perforated webs	22 to 16
Composite floor deck	Concrete slab, as reinforcement	1-1/2" and 3", normal or inverted	22 to 16
Form deck	Concrete slab, as a form only	9/16" × 3", 36" or 30" cover	26 to 22

Roof deck: 1-1/2" or 3"

The 1-1/2" deck with ribs at 6" and a 36" cover is the everyday profile under a membrane roof. The 3" deep-rib deck, on 6", 8" or 12" ribs, spans further and carries heavier roofs. Fastened and lapped sheet to sheet, either one ties the roof into a diaphragm.

Composite or form deck under concrete

Both hold the wet concrete during the pour. The difference is what happens after it cures:

Composite floor deck: embossed webs lock the slab to the steel, and the deck becomes the slab's bottom reinforcement.
Form deck: stays in place as a permanent form only; the reinforced slab carries the load on its own.

Accessories ordered with the deck

Each deck ships with the closures and plates that finish it: pour stop at slab edges, cover plates, ridge and valley plates, flute closures, cant strips and sump pans. Profile, gauge, span and fastening are set by the designer from the load tables for the product on the order.

Common questions

The deck questions we hear most.

What is B deck?

The common 1-1/2" deep roof deck with 6" rib spacing and a 36" cover, the usual choice under a membrane roof on open-web joists.

Composite deck or form deck?

Composite deck bonds to the concrete and works with the slab. Form deck only holds the wet concrete, and the slab is designed on its own.

What gauge is roof deck?

Commonly 22, 20, 18 or 16 gauge. The structural drawings set the gauge from the span and the load.