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Load-Span Tables
for PS-1 Plywood
Number Z802K
March 1998
Load-span tables for specific wood
structural panel applications are
included in several APA publications.
Recommended loads for sheathing and
flooring applications in these publications directly reflect minimum performance criteria given in Voluntary
Product Standard PS 1-95, Voluntary
Product Standard PS 2-92 and in
APA PRP-108 Performance Standards
and Policies for Structural-Use Panels.
To qualify for a given Span Rating under
these standards, a panel must meet all
of the criteria for that rating. As a result,
mechanical properties that are characteristic of APA wood structural panels
are actually greater than the minimum
necessary to pass one criterion.
Because it is sometimes necessary to
have engineering design information
for PS-1 plywood for conditions not
specifically covered in the other APA
literature, APA publishes separate
design section properties and working
stresses for the various grades and
thicknesses. These values are listed in
APA’s Plywood Design Specification
(PDS), and are recognized by the
model building codes. The uniform
loads in the following tables were
calculated using these properties and
stresses, or resulting section capacities
for the various Span Ratings. These
loads are recommended when
engineering principles are used for
design. It is important to remember
that structural engineering principles
alone do not necessarily take into
account other factors, such as moisture and thermal conditions, which
may impact design.
The following load-span tables apply to
sanded, touch-sanded, and unsanded
plywood manufactured in accordance
with Voluntary Product Standard
PS 1-95, with face grain parallel to supports, and face grain across supports. For
each combination of span and thickness
(or Span Rating), loads are given for
deflections of L/360, L/240 and L/180,
and maximum loads controlled by bending and shear capacity. Uniform loads for
some applications can be read directly
from the tables. In other cases, the values
given in the tables should be adjusted for
special conditions using the factors listed
in the “Table of Adjustment Factors.”
Table 1 applies to unsanded plywood
and is based on APA RATED SHEATHING (marked PS 1) grade. For touchsanded grades such as C-D Plugged,
C-C Plugged, UNDERLAYMENT and
APA RATED STURD-I-FLOOR (marked
PS 1), see Table 2. Table 3 applies to
sanded grades such as A-D and B-D.
The tables also assume dry conditions,
normal duration of load, and untreated
plywood with interior glue. For other
conditions, the loads should be appropriately adjusted using the factors given. For
instance, roof loads based on bending
and shear stress may be increased 15%
for short duration of snow load. See the
examples for proper application of adjustment factors. Further details on plywood
stresses and adjustments are given in the
PLYWOOD DESIGN SPECIFICATION.
For face grain across supports, and spans
of 32" and less, three spans are assumed,
and two spans for spans greater than 32".
For face grain parallel to supports, tables
are based on three spans for spans of 16"
and less, and two spans for 24". The
tables do not apply directly to plywood
having a single span. For one-span conditions, use the span adjustment factors.
Effects of support width have been
considered when determining the loads
based on shear and deflection. Supports
are assumed to be 2x nominal members
for spans less than 48", and 4x members
for 48" and greater spans. Support-width
factors are those established by APA
Laboratory Report 120.
It is important to note that some plywood
applications are not controlled by uniform loads. Residential floors are a good
example. They are commonly designed
for 40 psf live load. The allowable uniform floor load on plywood applied at
maximum span according to APA recommendations is greatly in excess of the
typical design loads. This excess does not
mean that floor spans for plywood can be
increased, but only that there is considerable reserve strength and stiffness for
uniform loads. Actually, the recommendations for plywood floors are based on
performance under concentrated loads,
how the floor “feels” to passing foot
traffic, and other subjective factors which
relate to public acceptance. Always check
the maximum floor and roof spans for
plywood before making a final plywood
selection for these applications.
A P A
T h e E n g i n e e r e d Wo o d A s s o c i a t i o n
© 1998 APA - The Engineered Wood Association
©1998 APA – THE ENGINEERED WOOD ASSOCIATION • ALL RIGHTS RESERVED. • ANY COPYING, MODIFICATION, DISTRIBUTION OR OTHER USE OF THIS PUBLICATION OTHER THAN AS EXPRESSLY AUTHORIZED BY APA IS PROHIBITED BY THE U.S. COPYRIGHT LAWS.
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TABLE OF ADJUSTMENT FACTORS
Duration of Load (Applies to Bending and Shear Only):
Permanent load (over 10 years)
0.90
2 months, as for snow
1.15
7 days
1.25
Wind or earthquake (check local code)
1.6 or 1.33
Impact
2.00
Basic Stresses for Plywood Grades:
Exposure 1 or exterior glue
STRUCTURAL I
Groups 2 and 3 for sanded or touch sanded
(Tables 2 & 3)
Fire-Retardant Treatments:
Check with company providing the treatment and redrying service for
adjustment recommendations.
Wet or Damp Locations (Moisture Content 16% or more):
Exterior and Exposure 1 (Interior with exterior glue) only
Deflection
0.83
Bending
0.70
Shear
0.83
1.10 (shear)
1.56 (shear)
Span Adjustments:
2-span to 1-span
Deflection
Bending
Shear
3-span to 1-span
Deflection
Bending
Shear
0.73 (bending)
0.67 (deflection)
Group 4 for sanded or touch sanded
(Tables 2 & 3)
0.67 (bending)
0.56 (deflection)
Preservative Treatment:
No adjustment required
0.42
1.00
1.25
0.53
0.80
1.20
TABLE 1
UNIFORM LOADS (PSF) ON UNSANDED (SPAN RATED) PLYWOOD PANELS
MULTI-SPAN, NORMAL DURATION OF LOAD, DRY CONDITIONS
Span
Rating
Load
Governed
By
Face Grain Parallel to Supports
Span, Center-to-Center
of Supports (inches)
Face Grain Across Supports
Span, Center-to-Center of Supports (inches)
12
16
19.2
24
30
32
12/0
L/360
L/240
L/180
Bending
Shear
92
138
184
117
234
37
55
73
66
170
21
31
41
46
139
10
15
20
29
109
16/0
L/360
L/240
L/180
Bending
Shear
110
165
220
126
234
44
66
88
71
170
25
37
49
49
139
12
18
24
31
109
6
8
12
20
86
20/0
L/360
L/240
L/180
Bending
Shear
165
247
329
154
234
66
99
132
87
170
37
55
74
60
139
18
27
36
39
109
9
14
18
25
86
7
11
15
22
81
24/0
L/360
L240
L/180
Bending
Shear
278
417
556
208
284
114
171
227
117
206
64
96
129
81
168
32
48
64
52
132
16
24
32
33
105
13
20
26
29
98
11
17
23
19
83
32/16
L/360
L/240
L/180
Bending
Shear
420
631
841
293
358
181
271
362
165
259
105
157
209
114
212
53
80
106
73
167
27
40
54
47
132
22
33
44
41
123
19
29
39
26
105
14
21
28
21
94
40/20
L/360
L/240
L/180
Bending
Shear
657
985
1313
522
457
298
447
596
293
331
176
265
353
204
271
91
137
183
130
213
47
70
94
83
168
39
58
77
73
157
34
51
68
46
134
25
37
49
38
120
16
25
33
26
104
48/24
L/360
L/240
L/180
Bending
Shear
1073
1609
2145
646
590
511
767
1023
363
428
311
466
622
252
350
165
248
330
161
276
86
129
172
103
218
71
107
142
91
203
62
94
125
57
173
46
69
92
47
155
31
46
61
32
134
1-1/8"
(Groups
1 & 2)
L/360
L/240
L/180
Bending
Shear
1677
2516
3355
1047
911
904
1357
1809
589
659
590
885
1181
409
540
338
506
675
262
425
186
280
373
168
335
156
234
312
147
313
137
206
274
93
266
102
154
205
75
238
70
105
140
52
206
2
36
40
48
60
12
16
24
8
11
15
27
552
3
4
6
15
400
8
12
16
28
499
3
5
6
16
361
10
15
20
31
411
4
6
8
17
298
17
26
35
46
236
7
10
14
26
171
32
48
64
77
225
13
19
26
44
163
5
7
9
15
101
66
98
131
125
284
28
41
55
70
206
10
15
20
25
127
15
23
30
21
105
217
325
434
319
330
95
142
189
180
239
35
52
70
64
148
36
53
71
34
162
1062
1593
2124
768
725
515
773
1031
432
525
206
309
412
154
325
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TABLE 2
UNIFORM LOADS (PSF) ON TOUCH-SANDED (GROUP 1 OR SPAN RATED) PLYWOOD PANELS
MULTI-SPAN, NORMAL DURATION OF LOAD, DRY CONDITIONS
Thickness
Load
(inches)
Governed
or Span
By
Rating
Face Grain Parallel to Supports
Span, Center-to-Center
of Supports (inches)
Face Grain Across Supports
Span, Center-to-Center of Supports (inches)
12
16
19.2
24
30
32
36
40
48
60
12
16
24
40
61
81
84
251
17
25
34
47
182
6
9
12
17
113
1/2
or
16 oc
L/360
L/240
L/180
Bending
Shear
433
650
867
345
389
197
295
393
194
281
116
175
233
135
231
60
91
121
86
181
31
46
62
55
143
25
38
51
49
134
22
34
45
31
114
16
24
33
25
102
11
16
22
17
88
19/32,
5/8 or
20 oc
L/360
L/240
L/180
Bending
Shear
607
911
1214
401
490
275
413
551
225
354
163
245
326
157
290
85
127
169
100
228
43
65
87
64
180
36
54
71
56
169
31
47
63
36
143
23
34
46
29
128
15
23
30
20
111
7
11
15
13
87
109
164
219
186
295
46
69
92
105
214
17
25
33
37
132
23/32,
3/4 or
24 oc
L/360
L/240
L/180
Bending
Shear
915
1373
1831
535
602
436
655
873
301
436
265
398
531
209
357
141
211
282
134
281
73
110
147
86
222
61
91
121
75
207
53
80
107
48
176
39
59
78
39
158
26
39
52
27
136
13
19
26
17
107
197
295
393
287
333
86
129
171
161
241
32
47
63
57
149
1-1/8
2-4-1
(Groups 1,
2 or 3)
or 48 oc
L/360
L/240
L/180
Bending
Shear
1884
2826
3768
1343
1029
1016
1524
2032
755
745
663
995
1326
524
610
379
569
758
336
480
209
314
419
215
379
175
263
351
189
354
154
231
308
119
301
115
172
230
97
269
78
118
157
67
233
40
60
80
43
184
1202
1803
2405
1022
781
583
875
1167
575
566
233
349
466
204
350
3
© 1998 APA - The Engineered Wood Association
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TABLE 3
UNIFORM LOADS (PSF) ON GROUP 1 SANDED PLYWOOD PANELS
MULTI-SPAN, NORMAL DURATION OF LOAD, DRY CONDITIONS
Load
Thickness
Governed
(inches)
By
Face Grain Parallel to Supports
Span, Center-to-Center
of Supports (inches)
Face Grain Across Supports
Span, Center-to-Center of Supports (inches)
12
16
19.2
24
30
32
36
11/32
L/360
L/240
L/180
Bending
Shear
139
209
278
128
253
56
84
112
72
183
32
47
63
50
150
16
24
31
32
118
8
12
16
20
93
6
10
13
18
87
3/8
L/360
L/240
L/180
Bending
Shear
192
288
384
172
282
79
118
157
97
204
44
67
89
67
167
22
33
44
43
132
11
17
22
27
104
15/32
L/360
L/240
L/180
Bending
Shear
428
642
856
294
376
182
273
363
166
272
104
157
209
115
223
53
79
105
74
175
1/2
L/360
L/240
L/180
Bending
Shear
483
724
966
325
408
208
312
415
183
296
120
180
240
127
242
19/32
L/360
L/240
L/180
Bending
Shear
649
973
1297
433
500
290
435
581
244
362
5/8
L/360
L/240
L/180
Bending
Shear
701
1052
1403
466
532
23/32
L/360
L/240
L/180
Bending
Shear
40
48
60
12
16
24
6
8
11
11
74
8
12
16
22
237
3
5
6
12
171
1
2
2
4
106
9
14
18
24
97
8
12
16
15
82
12
18
23
32
321
5
7
9
18
232
2
2
3
6
144
27
40
53
47
139
22
33
43
41
129
19
29
38
26
110
14
21
28
21
98
9
14
18
15
85
45
68
90
92
223
18
27
36
52
161
6
10
13
18
100
61
91
122
81
191
31
46
62
52
150
25
38
50
46
141
22
33
44
29
119
16
24
32
23
107
11
16
21
16
92
63
95
126
120
252
26
38
51
67
182
9
14
18
24
113
171
256
342
169
297
88
132
176
108
233
45
67
90
69
184
37
55
74
61
172
33
49
65
39
146
24
35
47
31
131
16
23
31
22
113
8
12
15
14
89
143
215
286
188
262
60
89
119
106
189
21
32
43
38
117
318
477
636
262
386
188
283
377
182
316
98
147
195
117
248
50
75
100
75
196
41
62
82
66
183
36
54
72
41
156
26
40
53
34
139
17
26
35
23
121
9
13
17
15
95
180
270
360
226
285
76
113
151
127
206
27
41
54
45
128
870
1305
1740
535
602
410
615
819
301
436
247
371
495
209
357
131
196
261
134
281
68
102
136
86
222
56
84
112
75
207
49
74
98
48
176
36
54
72
39
158
24
36
48
27
136
12
18
24
17
107
311
466
621
318
349
134
201
268
179
253
49
74
98
64
156
3/4
L/360
L/240
L/180
Bending
Shear
922
1382
1843
567
618
439
659
879
319
448
267
401
534
221
367
142
213
284
142
289
74
111
148
91
228
61
92
122
80
213
54
81
107
50
181
39
59
79
41
162
26
39
52
28
140
13
20
26
18
110
382
573
764
392
373
166
250
333
220
270
61
92
123
78
167
7/8
L/360
L/240
L/180
Bending
Shear
1116
1675
2233
708
736
557
836
1115
398
533
347
521
695
277
437
189
284
378
177
343
100
151
201
113
271
83
125
167
100
253
73
110
146
63
215
54
81
108
51
193
36
54
72
35
167
18
27
36
23
131
570
855
1139
542
464
258
386
515
305
336
97
146
195
108
208
1
L/360
L/240
L/180
Bending
Shear
1460
2190
2920
913
812
760
1139
1519
514
588
485
727
970
357
482
271
406
541
228
379
147
220
293
146
299
122
183
244
128
280
107
161
215
81
237
80
119
159
66
213
54
81
108
46
184
27
41
54
29
145
912
1368
1824
813
643
427
641
855
457
466
166
249
332
163
288
1-1/8
L/360
L/240
L/180
Bending
Shear
1632
2448
3264
1128
904
880
1320
1760
634
654
574
861
1149
440
536
328
493
657
282
422
181
272
363
180
333
152
228
304
159
311
133
200
267
100
264
100
149
199
81
237
68
102
136
56
205
35
52
69
36
161
1199
1799
2399
1023
771
582
873
1164
575
558
232
349
465
205
345
4
© 1998 APA - The Engineered Wood Association
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Examples Showing Use of Plywood Load-Span Tables
Example 1: Find the allowable uniform floor load for APA RATED SHEATHING 32/16
Exposure 1. Assume 10 psf dead load, and face grain across supports 16" o.c. Unless
stated otherwise, assume floor deflection criteria to be L/360 under live load only and
L/240 under total load.
Load
Adjustment
Governed Load
for
Load
By
(psf) Exposure 1 (psf)
L/360
181
181
L/240
271
271
L/180
362
362
Bending
165
Shear
259
From Table 1, for Unsanded Panels with Face Grain Across Supports:
Allowable total load for floors is the least of loads for L/240, bending and shear.
Allowable total load is 165 psf.
Live load is the lesser of the load for L/360 and total load as determined above, minus
dead load.
165
x
1.10 =
285
L/360 = 181 psf
Total load – dead load = 165 – 10 = 155 psf
Allowable live load is 155 psf.
Note: Do not increase span even though the allowable uniform live load greatly exceeds the 40 psf design live load normally used for floor design. Recommended
maximum span reflects performance under concentrated and impact loads in addition to uniform load.
Example 2: Find allowable snow loads on
APA RATED SHEATHING 48/24 Exposure
1 if face grain is across supports spaced 32"
o.c. In question are several panels in the 1span condition. Deflection criteria are
L/240 under live load only and L/180
under total load. Assuming a 2-month
duration of load for snow, allowable loads
for bending and shear may be increased
15%. Assume 10 psf dead load supported
by the plywood.
Load
Governed
By
Adjustment
for Duration
of Load
Load
(psf)
Adjustment
for
Exposure 1
Adjustment
for Span
Adjusted
Load
(psf)
L/360
71
x
0.53
=
38
L/240
107
x
0.53
=
57
L/180
142
x
0.53
=
75
Bending
91
x
1.15
x
0.80
=
84
Shear
203
x
1.15
x
1.20
=
308
x
1.10
From Table 1, for Unsanded Panels with Face Grain Across Supports:
Allowable total load is the least of loads for L/180, bending and shear. Allowable total load is 75 psf.
Live load is the lesser of total load minus dead load (75 – 10 = 65 psf), and load at L/240 (57 psf).
In this case, live load is controlled by deflection of L/240: Allowable live load = 57 psf, or 55 psf (rounded to nearest 5 psf).
Example 3: Find allowable soil pressure
on 23/32" APA C-C Plugged Group 1
EXT if supports are 16" o.c. Face grain is
across supports. Deflection need not be
considered. Assume soil pressure is
permanent load.
From Table 2, for Group 1 Touch-Sanded
Panels with Face Grain Across Supports:
Load
Governed
By
Load
(psf)
Adjustment
for Duration
of Load
Adjustment
for
Moisture
Adjustment
for
Exterior Glue
Adjusted
Load
(psf)
L/360
436
x
.83
=
362
L/240
655
x
.83
=
544
L/180
873
x
.83
=
725
Bending
301
x
0.90
x
.70
=
190
Shear
436
x
0.90
x
.83
=
358
x
1.10
Allowable load = 190 psf.
5
© 1998 APA - The Engineered Wood Association
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We have field representatives in most
major U.S. cities and in Canada who can
help answer questions involving APA
trademarked products. For additional
assistance in specifying APA engineered
wood products, get in touch with your
nearest APA regional office. Call or write:
WESTERN REGION
7011 So. 19th St. ■ P.O. Box 11700
Tacoma, Washington 98411-0700
(253) 565-6600 ■ Fax: (253) 565-7265
EASTERN REGION
2130 Barrett Park Drive, Suite 102
Kennesaw, Georgia 30144-3681
(770) 427-9371 ■ Fax: (770) 423-1703
U.S. HEADQUARTERS
AND INTERNATIONAL
MARKETING DIVISION
7011 So. 19th St. ■ P.O. Box 11700
Tacoma, Washington 98411-0700
(253) 565-6600 ■ Fax: (253) 565-7265
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www.apawood.org
PRODUCT SUPPORT HELP DESK
(253) 620-7400
E-mail Address: help@apawood.org
(Offices: Antwerp, Belgium; Bournemouth,
United Kingdom; Hamburg, Germany;
Mexico City, Mexico; Tokyo, Japan.) For
Caribbean/Latin America, contact
headquarters in Tacoma.
The product use recommendations in this
publication are based on APA – The
Engineered Wood Association’s continuing
programs of laboratory testing, product
research, and comprehensive field experience. However, because the Association has
no control over quality of workmanship or
the conditions under which engineered wood
products are used, it cannot accept responsibility for product performance or designs as
actually constructed. Because engineered
wood product performance requirements
vary geographically, consult your local architect, engineer or design professional to
assure compliance with code, construction,
and performance requirements.
Form No. Z802
Revised March 1998/0100
A P A
T h e E n g i n e e r e d Wo o d A s s o c i a t i o n
© 1998 APA - The Engineered Wood Association