Allowable Floor Spans – US

Maximum Allowable Spans

The specific PJI designation needed for your application is easily determined by selecting the span needed and then by choosing the PJI that meets your span, spacing, and uniform loading criteria.

Tables 1 and 1a are for simple or multiple span applications respectively. The use of these tables will provide maximum spans for the indicated spacing and span conditions.

To illustrate the selection of a P3 Joist product, assume a design simple span of 16’‑1”. For architectural reasons limit the joist depth to 11‑7/8” and joist spacing to 19.2” on center. From the 9‑1/2” and 11‑7/8” entries in Table 1, look down the 19.2” o.c. spacing column. For depths of 9‑1/2”, select 9‑1/2” PJI 60, and from the 11‑7/8” depths, notice that any joist designation will work.

The allowable spans in the tables in this user guide indicate the allowable clear span for various joist spacings
under typical residential uniform floor loads (40 psf live load and 10 psf dead load) for glued-nailed systems.

In addition, floor sheathing must be field glued to the P3 Joist flanges using approved construction adhesives in order to achieve the P3 Joist allowable spans.

Use of these span tables is limited to uniform load conditions, and P3 floor Joist spans shall not exceed these allowable spans. P3 Joist can be used for other applications such as roofs and ceilings to support
line loads or concentrated loads, etc., when properly engineered, using the appropriate design properties in Tables19 and 20.

NOTES:

  1. Allowable clear span is applicable to simple-span or multiple-span residential floor construction with a design dead load of 10 psf and a live load of 40 psf. The live load deflection is limited to L/480. (L = span length in inches). Spans are based on duration factor (LDF) of 1.0. 
  2. Spans are based on a composite floor with glue-nailed sheathing meeting the requirements for APA Rated Sheathing STURD-I-FLOOR conforming to PS1 or PS2 with a minimum thickness of 19/32” (40/20 or 20 o.c.) for a joist spacing of 19.2” or less or with a minimum thickness of 23/32” (48/24 or 24 o.c.) for a joist spacing of 24” when floor sheathing is nailed only. Adhesive shall meet APA Specification AFG-01 or ASTM D3498.
    Spans shall be reduced to 12” when floor sheathing is nailed only.
  3. Minimum bearing length shall be 1-3/4” for the end bearings and 3-1/2” for the intermediate bearings. 
  4. Bearing or web stiffeners are required for all PJI Joist in the span tables if over 16” deep.
Allowable Spans for P3 Floor Joists – Simple Span Only – Table 1 – LDF= 1.0

Maximum floor span [ft] – Glued subfloor* – On center joist spacing [in]

Live Load Dead Load Series Depth [in] 12 16 19.2 24
40 10 PJI 40 9 1/2 18′-0″  16′-5″ 15′-6″ 14″-6″
 “  “ 11 7/8 21′-5″  19′-7″ 18′-6″ 16′-8″
 “  “ 14 24′-4″  22′-3″ 20′-6″ 18′-4″
 “  “ 16 26′-11″  24′-3″ 22′-1″ 19′-9″
 40  10 PJI 60 9 1/2 18′-11″  17′-4″ 16′-4″ 15′-3″
 “  “ 11 7/8 22′-7″  20′-8″ 19′-6″ 18′-2″
 “  “ 14 25′-9″  23′-6″ 22′-2″ 20′-8″
 “  “ 16 28′-6″  26′-0″ 24′-7″ 22′-10″
 40  10 PJI 80 11 7/8 24′-11″  22′-8″ 21′-4″ 19′-10″
 “  “ 14 28′-3″  25′-9″ 24′-3″ 22′-7″
 “  “ 16 31′-4″  28′-6″ 26′-10″ 25′-0″
 “  “ 18 34′-2″  31′-1″ 29′-3″ 27′-3″
 “  “ 20 36′-11″  33′-8″ 31′-8″ 29′-6″
 “  “ 22 39′-8″  36′-1″ 34′-0″ 31′-8″
 “  “ 24 42′-4″  28′-6″ 36′-4″ 33′-9″
 40  10 PJI 90 11 7/8 25′-7″  23′-3″ 21′-11″ 20′-5″
 “  “ 14 29′-0″  26′-5″ 24′-11″ 23′-2″
 “  “ 16 32′-1″  29′-3″ 27′-6″ 25′-5″
 “  “ 18 35′-1″  31′-11″ 30′-1″ 27′-11″
 “  “ 20 37′-11″  34′-6″  32′-6″ 30′-3″
 “  “ 22 40′-9″  37′-7″ 34′-11″ 32′-6″
 “  “ 24 43′-5″  39′-6″ 37′-3″ 34′-8″

*For other type floor assemblies, please contact EACOM at www.eacom.ca.
SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 psf = 47.88 Pa

 

Allowable Spans for P3 Floor Joists – Multiple Span Only – Table 1A – LDF= 1.0

Maximum floor span [ft] – Glued subfloor* – On center joist spacing [in]

Live Load Dead Load Series Depth [in] 12 16 19.2 24
40 10 PJI 40 9 1/2 19′-7″ 17′-11″ 16′-4″ 14′-7″
 “  “ 11 7/8 23′-5″ 20′-5″ 18′-7″ 16′-7″
 “  “ 14 25′-11″ 22′-5″ 20′-5″ 18′-3″
 “  “ 16 27′-11″ 24′-2″ 22′-0″ 19′-8″
 40  10 PJI 60 9 1/2 20′-8″ 18′-10″ 17′-9″ 16′-6″
 “  “ 11 7/8 24′-8″ 22′-6″ 21′-2″ 19′-7″
 “  “ 14 28′-0″ 25′-7″ 24′-1″ 19′-9″
 “  “ 16 31′-1″ 28′-4″ 24′-9″ 19′-9″
 40  10 PJI 80 11 7/8 27′-1″ 24′-8″ 23′-3″ 21′-7″
 “  “ 14 30′-10″ 28′-0″ 26′-5″ 23′-11″
 “  “ 16 34′-2″ 31′-1″ 29′-3″ 23′-11″
 “ 18 37′-3″ 33′-10″ 31′-11″ 29′-5″
 “  “ 20 40′-3″ 36′-8″ 24′-6″ 31′-0″
 “  “ 22 43′-3″ 39′-4″ 36′-4″ 31′-5″
 “  “ 24 46′-2″ 41′-6″ 37′-10″ 31′-5″
 40  10 PJI 90 11 7/8 27′-1″ 25′-4″ 23′-10″ 21′-10″
 “  “ 14 31′-8″ 28′-9″ 27′-1″ 23′-11″
 “  “ 16 35′-0″ 31′-10″ 29′-11″ 25′-11″
 “  “ 18 38′-3″ 34′-9″ 32′-9″ 30′-5″
 “  “ 20 41′-5″ 37′-8″ 35′-5″ 31′-5″
 “  “ 22 44′-5″ 40′-5″ 38′-0″ 31′-5″
 “  “ 24 47′-5″ 43′-1″ 39′-9″ 31′-5″

*For other type floor assemblies, please contact EACOM at www.eacom.ca.
SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 psf = 47.88 Pa

 

P3 Floor Joist – PJI 40 – Allowable Uniform Loads [PLF] – Table 2 – LDF= 1.0
9/12″ 11 7/8″ 14″ 16″
Live Load Total Load Live Load Total Load Live Load Total Load Live Load  Total Load
Clear Joist Span [ft] Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240
 6  281  325  325  325
 7  242  280  280  280
 8  212  246  246  246
 9  189  219  219  219
 10  170  197  197  197
 11 153  155  179  179  179
 12 118  133  165  165  165
 13 93  113  151  152  152
 14 75  98  128  131  141  141
 15 61  85  104  114  132  132
 16 51  75  86  100  124  124
 17 42  67  72  89  105  117  117
 18 36  60  61  79  89  104  110
 19 30  53  52  71  76  94  103
 20 26  48  45  64  65  85  89  93
 21  44  39  59  56  77  77  84
 22  39  34  53  49  70  67  77
 23  34  29  49  43  64  58  70
 24  30  26  45  38  59  52  65
 25  27  41  34  54  46  60
 26  38  30  50  41  55
 27  36  27  47  36  51
 28  33  43  33  48
 29  30  40  29  44
 30  27  38  27  42
 31  35  39

 

P3 Floor Joist – PJI 60 – Allowable Uniform Loads [PLF] – Table 3 – LDF= 1.0
9/12″ 11 7/8″ 14″ 16″
Live Load Total Load Live Load Total Load Live Load Total Load Live Load  Total Load
Clear Joist Span [ft] Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240
 6  281 325 325 325
 7 242 280 280 280
 8 212 246 246 246
 9  189 219 219 219
 10  170 197 197 197
 11 155 179 179 179
 12 141 142 165 165 165
 13 112 131 152 152 152
 14 90 122 141 141 141
 15 73 114 125 132 132 132
 16 60 104 103 124 124 124
 17 51 92 86 117 117 117
 18 43 82 73 110 107 110 110
 19 36 73 62 98 92 104 104
 20 31 62 53 89 79 99 99
 21  27 54 46 81 68 95 93 95
 22  47 40 74 59 90 81 90
 23  41 35 67 52 83 71 86
 24 36 31 62 46 76 63 83
 25 32 28 55 41 70 55 80
 26  29  49 36 65 49 76
 27  26 44 32 60 44 71
 28 39 29 56 40 66
 29 35 26 52 36 61
 30 32 47 32 57
 31  29 43 29 54

 

P3 Floor Joist – PJI 80 – Allowable Uniform Loads [PLF] – Table 4 – LDF= 1.0
11 7/8″ 14″ 16″
Live Load Total Load Live Load Total Load Live Load Total Load
Clear Joist Span [ft] Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240
 6  359  393  393
 7  309  338  338
 8  271  297  297
 9  241  264  264
 10  218  238  238
 11  198  217  217
 12  182  199  199
 13  168  184  184
 14  156  171  141
 15  146  160  160
 16  137  150  150
 17  119  129  141  141
 18  101  122  133  133
 19  86  115  125  126  126
 20  74  110  108  120  120
 21  64  104  93  114  114
 22  56  100  81  109  109
 23  49  95  71  104  97  104
 24  43  86  63  100  85  100
 25  38  76  56  96  76  96
 26  34  68  50  92  67  92
 27  30  60  44  85  60  89
 28  27  54  40  79  54  86
 29  49  36  72  49  83
 30  44  32  65  44  80
 31  40  29  59  40  76
 32  36  27  53  36  71
 33  33  49  33  66
 34  30  45  30  61

 

P3 Floor Joist – PJI 80 with Web Stiffeners – Allowable Uniform Loads [PLF] – Table5 – LDF= 1.0
18″ 20″ 22″ 24″
Live Load Total Load Live Load Total Load Live Load Total Load Live Load  Total Load
Clear Joist Span [ft] Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240
 12  263  263  263  263
 13  243  243  243  243
 14  225  225  225  225
 15  210  210  210  210
 16  197  197  197  197
 17  185  185  185  185
 18  175  175  175  175
 19  166  166  166  166
 20  158  158  158  158
 21  150  150  150  150
 22  143  143  143  143
 23  137  137  137  137
 24  121  132  132  132  132
 25  107  126  126  126  126
 26  95  121  120  121  121  121
 27  85  117  108  117  117  117
 28  76  112  96  112  112  112
 29  69  105  87  108  107  108  108
 30  62  98  78  105  97  105  105
 31  56  92  71  101  88  101  101
 32  51  86  65  95  80  98  97  98
 33  47  81 59  89  73  95  88  95
 34  43 76  54  84  67  92  81  92
 35  39  72  49  80  61  87  74  90
 36  36  68  45  75  56  82  68  87
 37  33  64  42  71  52  78  63  85
 38  30  61 39  67  48  74  58  80

 

P3 Floor Joist – PJI 90 – Allowable Uniform Loads [PLF] – Table 6 – LDF= 1.0
11 7/8″ 14″ 16″
Live Load Total Load Live Load Total Load Live Load Total Load
Clear Joist Span [ft] Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240
 12  182  199  213
 13  168  184  197
 14  156  171  183
 15  146  160  171
 16  137  150  160
 17  129  141  151
 18  122  133  142
 19  104  115  126  135
 20  89  110  120  128
 21  77  104  112  114  122
 22  67  100  98  109  116
 23  59  95  85  104  111
 24  52  92  75 100  102  107
 25  46  88  66  96  90  102
 26  41  81  59 92  80  98
 27  36  73  53  89  71  95
 28  33  65  47  86  64  91
 29  29  59  43  83  58  88
30  27  53  38  81  52  85
 31  24  48  35  78  47  83
 32  22  44  32  76  43 80
 33  20  40  29  73 39  78
 34  18  36  26  71  36  71
 35  17 33  24  48  33  65
 36  15  31  22  45  30  60
 37  14 28  21 41  28  55
 38  13  26 19  38  26  51

 

P3 Floor Joist – PJI 90 with Web Stiffeners – Allowable Uniform Loads [PLF] – Table 7 – LDF= 1.0
18″ 20″ 22″ 24″
Live Load Total Load Live Load Total Load Live Load Total Load Live Load  Total Load
Clear Joist Span [ft] Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240 Defl. L/480 Defl. L/240
 12  263  263  263  263
 13  243  243  243  243
 14  226  226  226  226
 15  211  211  211  211
 16  187  198  198  198
 17  186  186  186  186
 18  176  176  176  176
 19  166  166  166  166
 20  158  158  158  158
 21  150  150  150  150
 22  144  144  144  144
 23  137  137  137  137
 24  132  132  132  132  132
 25  117  126  126  126  126
 26  104  122  122  122  122
 27  93  117  117  117  117  117
 28  83  113  105  113  113  113
 29  75  109  94  109  109  109
 30  68  105  85  105  105  105  105
 31  61 102  77  102  95  102  102
 32  56  99  70  99  87  99  99
 33  51  96  64  96 79  96  96  96
 34  46 93  59  93  72  93  88  93
 35  43  85  54  90  66  90  80  90
 36  39  78  49  88  61  88 74  88
 37  36  72  45  85 56  85  68  85
 38  33  66  42  82  52  83  63  83

NOTES FOR TABLES 2,3,4,5,6, and 7:

  1. Live Load column limits deflection to L/480; Total Load column limits deflection to L/240.
  2. Values represent the most restrictive of simple span or multiple span conditions. 
  3. Values are for I-Joists spaced at a maximum of 24” on center
  4. Tables assume a minimum end bearing length of 1‑3/4” and a minimum interior bearing length of 3-1/2”. 
  5. Web stiffeners are not required for the joists in tables 2, 3, and 4. Web stiffeners are required for all joists at each support in Table 5 and Table 7.