Georgia-Pacific Engineered Lumber Canada - Manual (Page 12)

12
GeorGia-Pacific Wood Products
JaN 2014
caNadiaN iNstallatioN iNstructioNs
Pa
Ge
roof details
roof installation Guidelines
1. Installation of I-Joists must be as shown in
details 2A- 2L.
2. Except for cutting to length, or for providing
birdsmouth bearings as detailed in detail 2H,
I-Joist top or bottom flanges should NEVER
be cut, drilled or notched.
3. I-Joists are permitted to be birdsmouth cut
at the lower end of the joist only. The
birdsmouth cut must have full bearing and
not overhang the inside face of the plate.
Bearing / web stiffeners are required at the
birdsmouth cut on both sides of the web.
4. When beveled bearing plates are used at I-Joist
supports, I-Joist attachment to the bevel plate
must be designed to transfer lateral thrust.
5. Concentrated loads should only be applied
to the top surface of the top flange. At no
time should concentrated loads be suspended
from the bottom flange, with the exception of
light loads (lighting fixtures, ceiling fans, etc.).
6. I-Joists must be protected from the weather
prior to installation.
7. I-Joists must not be used in places where
they will be permanently exposed to weather
(overhangs are exceptionally vulnerable) or
in areas where they will reach a moisture
content greater than 16%, such as in a
swimming pool or hot-tub enclosure. They
must not be installed where they will be in direct
contact with concrete or masonry.
8.
9. Ends of roof joists must be restrained at the
bearing to prevent rollover. Rim Board or
I-Joist blocking panels are preferred.
Cantilever-end blocking must be placed at
the support adjacent to the cantilever, and
ends of all cantilever extensions must be
laterally braced by a fascia board or other
similar method.
10. Rim Board, I-Joist blocking panels, or other
means of providing lateral support must be
provided at all I-Joist bearing points.
11. Continuous lateral support of the I-Joist's
compression flange is required to prevent
rotation and buckling. In simple span roof
applications, lateral support of the top flange
is normally supplied by the roof sheathing.
Bracing of the I- Joist’s bottom flange is also
required at interior supports of multiple-span
joists and at the end support next to an
overhang. Lateral support of the entire bottom
flange may be required in cases of load reversal
such as those caused by high wind.
12. Nails installed perpendicular to the wide face
of the flange must be spaced in accordance
with the applicable building code
requirements or approved building plans but
should not be closer than 3 inches o.c.
per row using 8d common nails.
13.
14. The top and bottom flanges of the I-Joist
must be kept within½ inch of true alignment.
The use of I-Joist blocking panels or
engineered wood Rim Board greatly
simplifies this requirement.
15. All roof details are valid up to 12:12 slope
unless otherwise noted.
2A
2B 2C
2D
2G
2H 2I 2J 2K
Blocking panels not shown for clarity.
APA Rated OSB sheathing or equal.
Fasten according to
APA recommendations
Temporary
construction
bracing
End-bearing length must be at least 1¾ inches.
For continuous framing and roof framing
with cantilevers, the immediate support
and end bearing adjacent to the cantilever
both must be at least 3½ inches. For multiple-
span joists, intermediate bearing length must
be at least 3½ inches.
If I-Joists are oriented so that the knockouts
provide by the manufacturer are adjacent
to the top flange, they may be removed
to aid ventilation.