Rheem RS47-21BP Use & Care Manual page 13

Conventional Roof Modifications
Truss Frame Modifications
Determine the correct truss frame modification using the figures shown below.
2" x 4" Top Chord 2" x 6" Top Chord
21"
24"
25"
28"
28"
30"
NOTICE: For truss spans >36", use double 2" x 6" kicker.
¹
Pitch of 3:12 or less
Allowable Spans for Trusses
24" O.C. Kickers
32"
X
36"
X
38"
X
42"
X
36"
X
38"
X
²
Pitch of 4:12 to 6:12
Bottom Chord
2"x4" or 2"x6"
2"x4" or 2"x6"
2"x4" or 2"x6"
2"x4" or 2"x6"
2"x4" or 2"x6"
2"x4" or 2"x6"
³
Pitch of 7:12 or greater
Pitch Roof Material
3:12¹ Tile
3:12¹ Shake
4:12² Tile
4:12² Shake
7:12³ Tile
7:12³ Shake
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