Maximum Load Per Span for Type B Deck: Catalog Values
Florida has no state design manual listing Type B capacities. The Florida Building Code sets the minimum roof live load, and the deck manufacturer's tables give the allowable load per span. In our catalog, 1.5" Type B on double spans ranges from 138 psf at 5'-0" to 34 psf at 10'-0" for 22 gauge, and from 315 to 79 psf for 16 gauge.
Demand versus capacity
The code sets the demand: roof live load, rain load, dead load and wind. The catalog provides capacity: the allowable uniform superimposed load for each gauge, span and span condition. The engineer of record checks the total against the table and the deflection limit, whichever is lower.
Reading the table correctly
- Values are ASD allowable superimposed loads, not live load alone; dead load above the deck uses part of them.
- Spans are center to center of supports; do not use clear span.
- Deflection often controls on longer spans; check the L/240 table.
- Single and triple spans have their own values.
Next step
Send your spans and roof loads and we will quote the lightest gauge that your engineer confirms.
1.5" Type B ASD uniform downward load, double span, psf (catalog)
| Span | 22 ga | 20 ga | 18 ga | 16 ga |
|---|---|---|---|---|
| 5'-0" | 138 | 177 | 249 | 315 |
| 6'-0" | 96 | 123 | 173 | 219 |
| 7'-0" | 70 | 91 | 127 | 161 |
| 8'-0" | 54 | 69 | 97 | 123 |
| 9'-0" | 42 | 55 | 77 | 97 |
| 10'-0" | 34 | 44 | 62 | 79 |
Related Questions
Does the table include concentrated loads like rooftop units?
No. The tables cover uniformly distributed loads only. Rooftop units, hangers and other point loads need their own check, and heavy equipment is usually carried on framing rather than on the deck. The engineer of record designs those supports and any added framing at openings.
Does deflection or strength control Type B on long spans?
On longer single spans, deflection usually controls. At 10'-0" single span, 20 gauge allows 44 psf for strength but only 12 psf at L/240. Double spans are much stiffer, at 30 psf for the same case. Always check both tables before settling on a gauge.