Page 437 - 2018_IRC

ROOF-CEILING CONSTRUCTION

R803.2.1.2 Fire-retardant-treated plywood. The R804.1.1 Applicability limits. The provisions of this sec-
allowable unit stresses for fire-retardant-treated ply- tion shall control the construction of cold-formed steel
wood, including fastener values, shall be developed roof framing for buildings not greater than 60 feet (18 288
from an approved method of investigation that consid- mm) perpendicular to the joist, rafter or truss span, not
ers the effects of anticipated temperature and humidity greater than 40 feet (12 192 mm) in width parallel to the
to which the fire-retardant-treated plywood will be sub- joist span or truss, less than or equal to three stories above
jected, the type of treatment and redrying process. The grade plane and with roof slopes not less than 3:12 (25-
fire-retardant-treated plywood shall be graded by an percent slope) or greater than 12:12 (100-percent slope).
approved agency. Cold-formed steel roof framing constructed in accordance
R803.2.2 Allowable spans. The maximum allowable with the provisions of this section shall be limited to sites
spans for wood structural panel roof sheathing shall not where the ultimate design wind speed is less than 140
exceed the values set forth in Table R503.2.1.1(1), or APA miles per hour (63 m/s), Exposure Category B or C, and
E30. the ground snow load is less than or equal to 70 pounds
per square foot (3350 Pa).
R803.2.3 Installation. Wood structural panel used as roof
sheathing shall be installed with joints staggered or not R804.1.2 In-line framing. Cold-formed steel roof fram-
staggered in accordance with Table R602.3(1), APA E30 ing constructed in accordance with Section R804 shall be
for wood roof framing or with Table R804.3 for cold- located in line with load-bearing studs in accordance with
formed steel roof framing. Wood structural panel roof Figure R804.1.2 and the tolerances specified as follows:
sheathing in accordance with Table R503.2.1.1(1) shall not 1. The maximum tolerance shall be / inch (19.1 mm)
3
4
cantilever more than 9 inches (229 mm) beyond the gable between the centerline of the horizontal framing
endwall unless supported by gable overhang framing. member and the centerline of the vertical framing
member.
2. Where the centerline of the horizontal framing
SECTION R804
COLD-FORMED STEEL ROOF FRAMING member and bearing stiffener are located to one side
of the centerline of the vertical framing member, the
R804.1 General. Elements shall be straight and free of any maximum tolerance shall be / inch (3.2 mm)
1
8
defects that would significantly affect their structural perfor- between the web of the horizontal framing member
mance. Cold-formed steel roof framing members shall be in and the edge of the vertical framing member.
accordance with the requirements of this section.

HORIZONTAL
FRAMING HORIZONTAL
MEMBER FRAMING
MEMBER
BEARING STIFFENER
BEARING STIFFENER
TRACK
TRACK
STUD
STUD
C STUD
L
C L BEARING
STIFFENER
HORIZONTAL HORIZONTAL HORIZONTAL
C FRAMING C FRAMING FRAMING
L L C L
MEMBER MEMBER MEMBER
¾″ ¾″ ¾″
MAX. MAX. MAX.

1
8″ / MAX.
FROM WEB OF
HORIZONTAL
FRAMING
MEMBER TO
EDGE OF
VERTICAL
VERTICAL VERTICAL VERTICAL
C L FRAMING C L FRAMING FRAMING C L FRAMING
MEMBER MEMBER MEMBER MEMBER
For SI: 1 inch = 25.4 mm.
FIGURE R804.1.2
IN-LINE FRAMING

412 2018 INTERNATIONAL RESIDENTIAL CODE ®
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