What Is the Maximum Span for Type B Steel Deck?
Per our catalog, the longest construction span for 1.5" Type B runs from 8'-03" for 22 gauge single span to 23'-08" for 16 gauge on double or triple spans. These are construction-load spans, not design spans. In Florida, the engineer of record sets the design span from the full load and deflection tables for the actual roof and wind loads. We cut to the lengths your layout needs.
Construction span vs design span
Construction spans are based on a 200 lb load on a 1 ft width of deck, per ANSI/SDI RD-2017 and SD-2022. They answer whether the bare deck can be safely walked on and erected. The design span must also carry roof dead load, live load and wind uplift within the allowable loads and deflection limit, and that is usually shorter.
What shortens the span in Florida
- High wind uplift, especially at roof corners and edges.
- Heavy roof equipment or insulating fill.
- Deflection limits for ponding or finishes below.
- Single spans, which have less capacity than continuous spans of the same length.
- The catalog load tables stop at 10'-0"; longer spans need the engineer's own check.
Plan the layout
Run sheets over at least three supports where possible to use the higher multi-span values. Send your framing plan and we will quote sheet lengths that keep spans continuous.
1.5" Type B construction spans (200 lb load on a 1 ft width, ANSI/SDI RD-2017 and SD-2022)
| Gauge | Single span | Double or triple span | Cantilever |
|---|---|---|---|
| 22 | 8'-03" | 10'-02" | 2'-02" |
| 20 | 11'-00" | 13'-07" | 2'-09" |
| 18 | 14'-11" | 18'-05" | 3'-10" |
| 16 | 19'-03" | 23'-08" | 4'-10" |
Related Questions
How far can Type B cantilever?
The catalog cantilever construction spans are 2'-02" for 22 gauge, 2'-09" for 20, 3'-10" for 18 and 4'-10" for 16. They assume a 200 lb load on a 1 ft width plus a 10 psf uniform load. Roof edge cantilevers in Florida also face high uplift, so the engineer checks them for design loads too.
Why is the double span longer than the single span?
A sheet that runs continuously over three or more supports shares bending between spans, so each span carries load more efficiently than a simple span. That is why the catalog lists longer double or triple construction spans for every gauge. Order sheet lengths that keep spans continuous when the framing allows.