Table 33, Table 34 – Georgia-Pacific APA Engineered Wood Construction Guide - Roofs User Manual

Page 7

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ENGINEERED WOOD CONSTRUCTION GUIDE

FORM NO. E30V

© 2011 APA – THE ENGINEERED WOOD ASSOCIATION

WWW.APAWOOD.ORG

64

Roof Construction

TABLE 33

RECOMMENDED ROOF LOADS (PSF) FOR APA RATED SHEATHING WITH
STRENGTH AXIS PARALLEL TO SUPPORTS

(a)(b)

(OSB and 5-ply/5-layer plywood panels unless otherwise noted)

Panel Grade

Panel

Performance

Category

Span Rating

Maximum

Span

(in.)

Load at Maximum Span

Live

Total

APA STRUCTURAL I
RATED SHEATHING

7/16

15/32, 1/2
19/32, 5/8
23/32, 3/4

24/16
32/16
40/20
48/24

24

(c)

24
24
24

15
30

(d)

70

(e)

105

(f)

25
40

(d)

80

(e)

115

(f)

APA RATED
SHEATHING

7/16

15/32, 1/2
19/32, 5/8
23/32, 3/4

24/16
32/16
40/20
48/24

16
24

(c)

24
24

35
15

(g)

40

(h)

70

(e)

45
25

(g)

50

(h)

80

(e)

(a) For guaranteed or warranted roofs, contact membrane

manufacturer for acceptable deck.

(b) Provide edge support.
(c) Solid blocking recommended at panel ends for 24-inch span.
(d) For 4-ply plywood, reduce load by 10 psf.

(e) For 4-ply plywood, reduce load by 30 psf.
(f) For 4-ply plywood, reduce load by 45 psf.
(g) For 4-ply plywood, reduce load by 5 psf.
(h) For 4-ply plywood, reduce load by 15 psf.

TABLE 34

STIFFENER LOAD-SPAN TABLES FOR PREFRAMED APA PANEL ROOF DECKS

Douglas fir-Larch

Allowable Roof Live Load (psf)

(a)

Center-

to-Center

Purlin

Spacing

(b)

(ft)

Stiffener
Size and

Spacing

(in.)

Select Structural

No. 1 & Better

No. 1

No. 2

Defl.

(c)

Strength

(d)

Defl.

(c)

Strength

(d)

Defl.

(c)

Strength

(d)

Defl.

(c)

Strength

(d)

1.15 1.25

1.15

1.25

1.15

1.25

1.15

1.25

8

2 x 4@16

2 x 4@ 24

2 x 6@16

2 x 6@24
2 x 6@32

37
25

144

96
72

67
41

154

99

61

73
46

168
109

68

35
23

136

91

68

51
31

121

78
47

57

34

133

85
52

33
22

129

86
64

41

24
99
63

38

46
27

109

69
42

31
21

121

81

61

36

21

88
56
33

40
23
97

61

37

Southern Pine

Allowable Roof Live Load (psf)

(a)

Center-

to-Center

Purlin

Spacing

(b)

(ft)

Stiffener
Size and

Spacing

(in.)

Select Structural

No. 1 Dense

No. 1

No. 2

Defl.

(c)

Strength

(d)

Defl.

(c)

Strength

(d)

Defl.

(c)

Strength

(d)

Defl.

(c)

Strength

(d)

1.15 1.25

1.15

1.25

1.15

1.25

1.15

1.25

8

2 x 4@16

2 x 4@24

2 x 6@16

2 x6@24
2 x 6@32

35
23

136

91

68

87
55

205

133

83

96
60

223

146

91

35
23

136

91

68

58
35

137

88
54

64
39

150

97
60

33
22

129

86
64

53
32

129

83
50

59
36

141

91

56

31
21

121

81

61

41

24
95
60
36

46
27

104

66
40

(a) Final allowable load is the lesser of the loads as determined by

deflection and stress.

(b) Actual span of stiffeners taken as 3-1/2 inches less than

center-to-center spacing of purlins.

(c) Deflection limitations: Span/240 under live load only; Span/180

under total load, assuming a dead load of 10 psf.

(d) Loads limited by stress are based on two conditions of duration

of load: two months, such as for snow (1.15); and seven days

(1.25); includes effects of 10 psf dead load.

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