6″ Box Rib
6″ Rib is currently the most popular and widely used panel for decking. Type 6″ Rib is frequently used for several applications such as flooring, siding, and roofing.

Notes
- An asterisk (*) indicates allowable stress has been reached.
- A strikethrough (
100) indicates less than 10 small PSF ASCE minimum. - For structural roofing & siding made of formed metal sheets, a total load deflection shall not exceed L/60.
- Refer to Table 1604.3 limits and footnotes of the International Building Code (IBC) for additional guidance.
- Allowable spans and loads DO include self-weight of panel.
- All values are for one foot of panel width unless noted otherwise.
- Yield stress = Fy = 33,000 psi.
- Loads and spans for carbon steel are based on AISI Standard for Design of Cold-Formed Steel Structure Members (2007 Edition).
- Yield stress = Fcy = 13,000 PSI.
- Loads and spans for aluminum are based on Aluminum Design Manual (January 2005).
PRODUCT CHARACTERISTICS
Load Table
Section | Weight | Total Cross-Sectional Area A (in2) |
Allowable Stress Fa (psi) |
Top Flat in Compression | Bottom Flat in Compression | |||||
---|---|---|---|---|---|---|---|---|---|---|
Sheet lb/ft |
Area lb/sf |
Moment of Inertia I (in4/ft) |
Section Modulus S (in3/ft) |
Allowable Momen Ma (lb-ft/ft) |
Moment of Inertia I (in4/ft) |
Section Modulus S (in3/ft) |
Allowable Moment Ma (lb-ft/ft) |
|||
18 Ga | 8.24 | 2.70 | 2.42 | 19760 | 0.291 | 0.322 | 530 | 0.261 | 0.395 | 650 |
20 Ga | 6.60 | 2.16 | 1.94 | 19760 | 0.233 | 0.258 | 425 | 0.196 | 0.285 | 469 |
22 Ga | 5.12 | 1.68 | 1.50 | 19760 | 0.180 | 0.200 | 330 | 0.141 | 0.196 | 322 |
24 Ga | 4.46 | 1.46 | 1.31 | 19760 | 0.153 | 0.169 | 278 | 0.119 | 0.160 | 264 |
0.05 Alum | 2.87 | 0.94 | 2.42 | 5304 | 0.291 | 0.322 | 230 | 0.291 | 0.489 | 231 |
0.04 Alum | 2.29 | 0.75 | 1.94 | 4434 | 0.233 | 0.258 | 168 | 0.233 | 0.394 | 153 |
0.032 Alum | 1.84 | 0.60 | 1.55 | 3821 | 0.186 | 0.208 | 125 | 0.186 | 0.319 | 107 |
Table 1: Applied Load (PSF)
An asterisk (*) indicates allowable stress has been reached.
Table 1 | Applied Load (PSF) | |||||||
---|---|---|---|---|---|---|---|---|
Allowable Spans | 10 | 20 | 30 | 40 | 50 | 60 | ||
Section | Span Limit | Span Type | Allowable Spans (ft) | |||||
18 Ga | L/60 | 1 Span | 17′-5″ | 13′-8″ * | 11′-5″ * | 10′-0″ * | 9-0″ * | 8′-3″ * |
2 Span | 20′-3″ * | 15′-2″ * | 12′-7″ * | 11′-0″ * | 9′-11″ * | 9′-1″ * | ||
3 Span | 19′-10″ | 15′-2″ * | 12′-8″ * | 11′-1″ * | 10′-0″ * | 9′-2″ * | ||
L/240 | 1 Span | 11′-0″ | 9′-1″ | 8′-0″ | 7′-4″ | 6′-10″ | 6′-5″ | |
2 Span | 12′-9″ | 10′-6″ | 9′-4″ | 8′-6″ | 7′-11″ | 7′-6″ | ||
3 Span | 12′-6″ | 10′-3″ | 9′-1″ | 8′-4″ | 7′-9″ | 7′-4″ | ||
20 Ga | L/60 | 1 Span | 16′-1″ | 12′-5″ * | 10′-3″ * | 9′-0″ * | 8′-1″ * | 7′-5″ * |
2 Span | 17′-7″ * | 13′-0″ * | 10′-10″ * | 9′-5″ * | 8′-6″ * | 7′-9″ * | ||
3 Span | 18′-2″ * | 13′-5″ * | 11′-2″ * | 9′-9″ * | 8′-9″ * | 8′-0″ * | ||
L/240 | 1 Span | 10′-2″ | 8′-4″ | 7′-4″ | 6′-8″ | 6′-3″ | 5′-11″ | |
2 Span | 12′-0″ | 9′-10″ | 8′-8″ | 7′-11″ | 7′-5″ | 7′-0″ | ||
3 Span | 11′-9″ | 9′-7″ | 8′-6″ | 7′-9″ | 7′-3″ | 6′-10″ | ||
22 Ga | L/60 | 1 Span | 14′-7″ | 10′-11″ * | 9′-0″ * | 7′-10″ * | 7′-1″ * | 6′-6″ * |
2 Span | 14′-10″ * | 10′-11″ * | 9′-0″ * | 7′-10″ * | 7′-1″ * | 6′-6″ * | ||
3 Span | 15′-4″ * | 11′-3″ * | 9′-4″ * | 8′-2″ * | 7′-4″ * | 6′-8″ * | ||
L/240 | 1 Span | 9′-2″ | 7′-6″ | 6′-7″ | 6′-0″ | 5′-7″ | 5′-3″ | |
2 Span | 11′-2″ | 9′-1″ | 8′-0″ | 7′-4″ | 6′-10″ | 6′-5″ | ||
3 Span | 10′-11″ | 8′-11″ | 7′-10″ | 7′-2″ | 6′-8″ | 6′-3″ | ||
24 Ga | L/60 | 1 Span | 13′-7″ * | 9-11″ * | 8′-2″ * | 7′-2″ * | 6′-5″ * | 5′-10″ * |
2 Span | 13′-7″ * | 9-11″ * | 8′-2″ * | 7′-2″ * | 6′-5″ * | 5′-10″ * | ||
3 Span | 14′-0″ * | 10′-5″ * | 8′-6″ * | 7′-4″ * | 6′-7″ * | 6′-1″ * | ||
L/240 | 1 Span | 8′-9″ | 7′-1″ | 6′-3″ | 5′-8″ | 5′-4″ | 5′-0″ | |
2 Span | 10′-8″ | 8′-8″ | 7′-8″ | 6′-11″ | 6′-5″ * | 5′-10″ * | ||
3 Span | 10′-5″ | 8′-5″ | 7′-5″ | 6′-9″ | 6′-4″ | 5′-11″ | ||
0.32 Alum | L/60 | 1 Span | 8′-9″ * | 6′-3″ * | 5′-2″ * | 4′-6″ * | 4′-0″ * | 3′-8″ * |
2 Span | 8′-9″ * | 6′-3″ * | 5′-2″ * | 4′-6″ * | 4′-0″ * | 3′-8″ * | ||
3 Span | 9′-1″ * | 6′-6″ * | 5′-4″ * | 4′-7″ * | 4′-2″ * | 3′-9″ * | ||
L/240 | 1 Span | 7′-4″ | 5′-11″ | 5′-2″ | 4′-6″ * | 4′-0″ * | 3′-8″ * | |
2 Span | 8′-3″ | 6′-3″ * | 5′-2″ * | 4′-6″ * | 4′-0″ * | 3′-8″ * | ||
3 Span | 8′-0″ | 6′-5″ | 5′-4″ * | 4′-7″ * | 4′-2″ * | 3′-9″ * | ||
0.04 Alum | L/60 | 1 Span | 10′-5″ * | 7′-6″ * | 6′-2″ * | 5′-4″ * | 4′-9″ * | 4′-5″ * |
2 Span | 10′-5″ * | 7′-6″ * | 6′-2″ * | 5′-4″ * | 4′-9″ * | 4′-5″ * | ||
3 Span | 10′-9″ * | 7′-9″ * | 6′-4″ * | 5′-6″ * | 4′-11″ * | 4′-6″ * | ||
L/240 | 1 Span | 7′-10″ | 6′-4″ | 5′-6″ | 5′-0″ | 4′-8″ | 4′-5″ * | |
2 Span | 8′-10″ | 7′-1″ | 6′-2″ * | 5′-4″ * | 4′-9″ * | 4′-5″ * | ||
3 Span | 8′-7″ | 6′-11″ | 6′-1″ | 5′-6″ | 4′-11″ * | 4′-6″ * | ||
0.05 Alum | L/60 | 1 Span | 12′-7″ * | 9′-1″ * | 7′-6″ * | 6′-6″ * | 5′-10″ * | 5′-4″ * |
2 Span | 12′-7″ * | 9′-1″ * | 7′-6″ * | 6′-6″ * | 5′-10″ * | 5′-4″ * | ||
3 Span | 13′-0″ * | 9′-5″ * | 7′-9″ * | 6′-9″ * | 6′-0″ * | 5′-6″ * | ||
L/240 | 1 Span | 8′-5″ | 6′-9″ | 5′-11″ | 5′-5″ | 5′-1″ | 4′-9″ | |
2 Span | 9′-5″ | 7′-7″ | 6′-8″ | 6′-1″ | 5′-8″ | 5′-4″ * | ||
3 Span | 9′-3″ | 7′-5″ | 6′-6″ | 5′-11″ | 5′-6″ | 5′-2″ |
TABLE 2: TRIAL SPAN (FT)
An asterisk (*) indicates allowable stress has been reached. A strikethrough (100) indicates less than 10 small PSF ASCE minimum.
Table 2 | Trial Span (ft) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Allowable Loads | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | ||
Section | Span Limit | Span Type | Allowable Loads (PSF) | |||||||||
18 Ga | L/60 | 1 Span | 368 * | 262 * | 166 * | 115 * | 83 * | 63 * | 49 * | 39 * | 32 * | 26 * |
2 Span | 575 * | 322 * | 205 * | 141 * | 103 * | 78 * | 61 * | 49 * | 40 * | 33 * | ||
3 Span | 579 * | 325 * | 207 * | 142 * | 104 * | 79 * | 62 * | 49 * | 40 * | 33 * | ||
L/240 | 1 Span | 468 * | 260 | 131 | 75 | 46 | 30 | 20 | 14 | |||
2 Span | 575 * | 322 * | 205 * | 120 | 74 | 49 | 33 | 23 | 17 | 12 | ||
3 Span | 579 * | 325 * | 194 | 111 | 69 | 45 | 31 | 21 | 15 | 11 | ||
20 Ga | L/60 | 1 Span | 375 * | 210 * | 133 * | 92 * | 67 * | 51 * | 39 * | 31 * | 25 * | 21 * |
2 Span | 415 * | 232 * | 148 * | 102 * | 74 * | 56 * | 44 * | 35 * | 28 * | 23 * | ||
3 Span | 443 * | 248 * | 158 * | 109 * | 79 * | 60 * | 47 * | 37 * | 30 * | 25 * | ||
L/240 | 1 Span | 375 * | 195 | 99 | 56 | 34 | 22 | 15 | 10 | |||
2 Span | 415 * | 232 * | 148 * | 96 | 59 | 39 | 26 | 19 | 13 | 10 | ||
3 Span | 443 * | 248 * | 155 | 89 | 55 | 36 | 24 | 17 | 12 | |||
22 Ga | L/60 | 1 Span | 284 * | 159 * | 101 * | 69 * | 50 * | 38 * | 30 * | 24 * | 19 * | 16 * |
2 Span | 284 * | 159 * | 101 * | 69 * | 50 * | 38 * | 30 * | 24 * | 19 * | 16 * | ||
3 Span | 304 * | 170 * | 108 * | 74 * | 54 * | 41 * | 32 * | 25 * | 21 * | 17 * | ||
L/240 | 1 Span | 284 * | 140 | 71 | 40 | 24 | 16 | 10 | ||||
2 Span | 284 * | 159 * | 101 * | 69 * | 46 | 30 | 20 | 14 | 10 | |||
3 Span | 304 * | 170 * | 108 * | 68 | 42 | 28 | 19 | 13 | ||||
24 Ga | L/60 | 1 Span | 232 * | 130 * | 82 * | 57 * | 41 * | 31 * | 24 * | 19 * | 15 * | 13 * |
2 Span | 232 * | 130 * | 82 * | 57 * | 41 * | 31 * | 24 * | 19 * | 15 * | 13 * | ||
3 Span | 248 * | 139 * | 88 * | 61 * | 44 * | 33 * | 26 * | 21 * | 17 * | 14 * | ||
L/240 | 1 Span | 232 * | 117 | 59 | 33 | 20 | 13 | |||||
2 Span | 232 * | 130 * | 82 * | 57 * | 39 | 25 | 17 | 12 | ||||
3 Span | 248 * | 139 * | 88 * | 58 | 36 | 23 | 16 | 11 | ||||
0.32 Alum | L/60 | 1 Span | 89 * | 50 * | 31 * | 21 * | 15 * | 12 * | ||||
2 Span | 89 * | 50 * | 31 * | 21 * | 15 * | 12 * | ||||||
3 Span | 95 * | 53 * | 34 * | 23 * | 17 * | 12 * | 10 * | |||||
L/240 | 1 Span | 89 * | 50 * | 31 * | 18 | 11 | ||||||
2 Span | 89 * | 50 * | 31 * | 21 * | 15 * | 10 | ||||||
3 Span | 95 * | 53 * | 34 * | 23 * | 15 | 10 | ||||||
0.04 Alum | L/60 | 1 Span | 128 * | 72 * | 45 * | 31 * | 23 * | 17 * | 13 * | 10 * | ||
2 Span | 128 * | 72 * | 45 * | 31 * | 23 * | 17 * | 13 * | 10 * | ||||
3 Span | 137 * | 76 * | 48 * | 33 * | 24 * | 18 * | 14 * | 11 * | ||||
L/240 | 1 Span | 128 * | 72 * | 40 | 23 | 14 | ||||||
2 Span | 128 * | 72 * | 45 * | 31 * | 20 | 13 | ||||||
3 Span | 137 * | 76 * | 48 * | 31 | 19 | 12 | ||||||
0.05 Alum | L/60 | 1 Span | 191 * | 107 * | 68 * | 47 * | 34 * | 26 * | 20 * | 16 * | 13 * | 11 * |
2 Span | 191 * | 107 * | 68 * | 47 * | 34 * | 26 * | 20 * | 16 * | 13 * | 11 * | ||
3 Span | 204 * | 114 * | 72 * | 50 * | 36 * | 27 * | 21 * | 17 * | 14 * | 11 * | ||
L/240 | 1 Span | 191 * | 101 | 51 | 29 | 18 | 11 | |||||
2 Span | 191 * | 107 * | 68 * | 41 | 26 | 17 | 11 | |||||
3 Span | 204 * | 114 * | 67 | 38 | 24 | 15 | 10 |
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