Georgia-Pacific APA Engineered Wood Roofs User Manual
Engineered Wood
C O N S T R U C T I O N G U I D E
Engineered Wood Construction Guide
©2011 APA – THE ENGINEERED WOOD ASSOC IATION • ALL RIGHTS RESERVED. • ANY COPYING, MODIFI CATION, DISTRIBUTION OR OTHER USE OF THIS PUBLICATION OTHER THAN AS EXPRESSLY AUTHORIZED BY APA IS PROHIBITED BY THE U.S. COPYRIGHT LAWS.
Engineered wood products are a good choice for the environment. They are
manufactured for years of trouble-free, dependable use. They help reduce waste
by decreasing disposal costs and product damage. Wood is a renewable resource
that is easily manufactured into a variety of viable products.
A few facts about wood.
■
We’re growing more wood every day. Forests fully cover one-third of the
United States’ and one-half of Canada’s land mass. American landowners
plant more than two billion trees every year. In addition, millions of trees seed
naturally. The forest products industry, which comprises about 15 percent of
forestland ownership, is responsible for 41 percent of replanted forest acreage.
That works out to more than one billion trees a year, or about three million trees planted every
day. This high rate of replanting accounts for the fact that each year, 27 percent more timber is
grown than is harvested. Canada’s replanting record shows a fourfold increase in the number of
trees planted between 1975 and 1990.
■
A 200 4 Consort ium for Research on Renewable Industrial Materia ls
(CORRIM) study gave scientific validation to the strength of wood as a
green building product. In examining building products’ life cycles – from
extraction of the raw material to demolition of the building at the end of its
long lifespan – CORRIM found that wood was better for the environment than steel or concrete
in terms of embodied energy, global warming potential, air emissions, water emissions and solid
waste production. For the complete details of the report, visit www.CORRIM.org.
■
Manufactur ing wood is energ y effic ient.
Wood products made up 47 percent of all
industrial raw materials manufactured in the
United States, yet consumed only 4 percent of the
energy needed to manufacture all industrial raw
materials, according to a 1987 study.
■
Good news for a healthy planet. For every ton of wood grown, a young forest
produces 1.07 tons of oxygen and absorbs 1.47 tons of carbon dioxide.
WOOD
The Natural Choice
Life Cycle Assessment shows wood is the greenest building product.
Percent of Percent of
Material Production Energy Use
Wood 47 4
Steel 23 48
Aluminum 2 8
Wood: It’s the natural choice for the environment, for design and for strong,
lasting construction.
NOT ICE :
The recommendations
in this guide apply only
to products that bear
the APA trademark.
Only products bearing
the APA trademark
are subject to the
Association’s quality
auditing program.
ENGINEERED WOOD CONSTRUCTION GUIDE ■ FORM NO. E30V ■ © 2011 APA – THE ENGINEERED WOOD ASSOCIATION ■ WWW.APAWOOD.ORG
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Engineered Wood Construction Guide
APA engineered wood products are used in a wide range
of construction applications. Time-tested panel products
are used in traditional wood-frame construction and in
combination with other engineered wood products and
systems. For low in-place cost, versatility, and superior
performance, engineered wood systems are simply hard
to beat.
This guide from APA is designed as a reference manual
for both residential and commercial construction. It
contains up-to-date information on APA Performance
Rated panels, glulam, I-joists, structural composite
lumber, specification practices, floor, wall and roof
systems, diaphragms and shear walls, fire-rated systems
and methods of finishing.
If what you want to know about engineered wood
construction systems isn’t fully explained here, chances
are it is in one of our many other publications. Titles cited
throughout this publication can be downloaded or ordered
from the APA website, at www.apawood.org. Or, for
individual assistance with specific application questions or
problems, contact the APA Product Support Help Desk at
(253) 620-7400.
ENGINEERED WOOD CONSTRUCTION GUIDE ■ FORM NO. E30V ■ © 2011 APA – THE ENGINEERED WOOD ASSOCIATION ■ WWW.APAWOOD.ORG
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ROOF CONSTRUCTION
APA Panel Roof Sheathing
The recommendations for roof sheathing in Table 30 apply to APA RATED SHEATHING Exposure 1 or Exterior, APA
STRUCTURAL I R ATED SHEATHING Exposure 1 or Exterior and APA RATED STURD-I-FLOOR Exposure 1 or
Exterior. Uniform load def lection limits are 1/180 of span under live load plus dead load, and 1/240 under live load
TABLE 30
RECOMMENDED UNIFORM ROOF LIVE LOADS FOR APA RATED SHEATHING
WITH STRENGTH AXIS PERPENDICULAR TO SUPPORTS
(b)
Maximum Span (in.) Allowable Live Loads (psf)
Panel Minimum Panel Spacing of Supports Center-to-Center (in.)
Span Performance With Edge Without Edge
Rating Category Support
APA RATED SHEATHING
(a)
(c)
Support 12 16 20 24 32 40 48 60
12/0 3/8 12 12 30
16/0 3/8 16 16 70 30
20/0 3/8 19.2 19.2 120 50 30
24/0 3/8 24 19.2
(e)
190 100 60 30
24/16 7/16 24 24 190 100 65 40
32/16 15/32 32 28 300 165 110 65 30
40/20 19/32 40 32 — 275 195 120 60 30
48/24 23/32 48 36 — — 270 175 95 45 30
60/32
60/48
APA RATED STURD-I-FLOOR
(f)
7/8 60 40 — — — 305 165 100 70 35
(f)
1-1/8 60 48 — — — 305 165 100 70 35
(g)
16 oc 19/32 24 24 185 100 65 40
20 oc 19/32 32 32 270 150 100 60 30
24 oc 23/32 48 36 — 240 160 100 50 30 20
32 oc 7/8 48 40 — — 295 185 100 55 35
48 oc 1-3/32 60 48 — — — 290 160 100 65 40
(a) Includes APA RATED SHEATHING/CEILING DECK.
(b) Applies to APA RATED SHE ATHING and APA RATED STURD-I-
FLOOR panels 24 inches or wider applied over two or more spans.
(c) Tongue-and-groove edges, panel edge clips (one midway*
between each support, except two equally spaced between supports 48 inches on center or greater), lumber blocking, or other.
For low slope roofs, see Table 31.
(d) 10 psf dead load assumed.
(e) 19.2 inches for Performance Categor y 3/8 and 7/16 panels.
24 inches for Performance Category 15/32 and 1/2 panels.
(f) Check with supplier for availability.
(g) Also applies to C-C Plugged grade ply wood.
*No established tolerance.
(a)
AND APA RATED STURD-I-FLOOR
(d)
ENGINEERED WOOD CONSTRUCTION GUIDE ■ FORM NO. E30V ■ © 2011 APA – THE ENGINEERED WOOD ASSOCIATION ■ WWW.APAWOOD.ORG
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Roof Construction
only. Special conditions, such as heavy concentrated loads, may require constructions in
excess of these minimums, or allowable live
loads may have to be decreased for dead loads
greater than 10 psf, such as tile roofs. Panels
are assumed continuous over two or more
spans with the long dimension or strength
axis across supports.
Good performance of built-up, single-ply, or
modified bitumen roofing applied on low slope
roofs requires a stiffer deck than does prepared
roofing applied on pitched roofs. Although
APA Span-Rated panels used as roof sheathing
at maxi mum span are adequate structurally,
an upgraded system is recommended for low
slope roofs. Table 31 provides recommended
maximum spans for low slope roof decks.
Recommended live loads can be determined
TABLE 31
RECOMMENDED MAXIMUM SPANS FOR APA PANEL ROOF
DECKS FOR LOW SLOPE ROOFS
(a)
(Panel strength axis
perpendicular to supports and continuous over two or more spans)
Grade
Minimum Panel
Performance
Category
Minimum
Span
Rating
Maximum
Span
(in.)
Panel Clips
Per Span
(b)
(number)
15/32 32/16 24 1
APA RATED
SHEATHING
19/32 40/20 32 1
23/32 48/24 48 2
7/8 60/32 60 2
APA RATED
STURD-I-FLOOR
(a) Low slope roofs are applicable to built-up, single-ply and modified bitumen roof-
ing systems.
for acceptable deck. Low-slope roofs have a slope that is less than 2/12 (2"/foot).
(b) Edge support may also be provided by tongue-and-groove edges or solid
blocking.
For guaranteed or warranted roofs contact membrane manufacturer
19/32 20 oc 24 1
23/32 24 oc 32 1
7/8 32 oc 48 2
FIGURE 21
APA PANEL ROOF SHEATHING
1/8" spacing is
recommended at all
edge and end joints
unless otherwise
indicated by panel
manufacturer
APA RATED
Panel clip or tongue-and-groove
edges if required
panel
clip
Strength axis
Stagger
end joints
(optional)
SHEATHING
Protect
edges of
Exposure 1
panels against
Asphalt or wood
shingles or shakes.
Follow roofing manufacturer’s
recommendations for roofing felt.
Notes:
1. Cover sheathing as soon as possible with roofing felt for extra
protection against excessive moisture prior to roofing application.
2. For pitched roofs, place screened surface or side with
skid-resistant coating up if OSB panels are used. Keep roof
surface free of dirt, sawdust and debris, and wear skid-resistant
shoes when installing roof sheathing.
3. For buildings with conventionally framed roofs (trusses or rafters),
limit the length of continuous sections of roof area to 80 feet
maximum during construction, to allow for accumulated expansion
in wet weather conditions. Omit roof sheathing panels in each
course of sheathing between sections, and install “fill in” panels later
to complete roof deck installation prior to applying roofing.
exposure to
weather, or use
Exterior panel
starter strip
TABLE 32
RECOMMENDED MINIMUM FASTENING SCHEDULE
FOR APA PANEL ROOF SHEATHING (Increased nail
schedules may be required in high wind zones and
where roof is engineered as a diaphragm.)
(a)(b)
Nailing
Maximum Spacing (in.)
Panel
Performance
Category
3/8 − 1 8d 6 12
1-1/8 8d or 10d 6 12
(a) Use common smooth or deformed shank nails for panels with
Performance Category 1 or smaller. For 1-1/8 Performance
Category panels, use 8d ring- or screw-shank or 10d common
smooth-shank nails.
(b) Other code-approved fasteners may be used.
(c) For stapling asphalt shingles to Performance Category 3/8 and
thicker panels, use staples with a 15/16-inch minimum crown
width and a 1-inch leg length. Space according to shingle manu-
facturer’s recommendations.
(d) See Table 5, page 14, for nail dimensions.
(e) Supported panel joints shall occur approximately along the
centerline of framing with a minimum bearing of 1/2". Fasteners
shall be located 3/8 inch from panel edges.
(f) For spans 48 inches or greater, space nails 6 inches at all
supports.
(c)
Size
(d)
Supported
Panel Edges
(e)
Intermediate
(f)
(f)
Notes: Gluing of roof sheathing to fram ing is not recom mended,
except when recommended by the adhesive manufacturer for roof
sheathing that already has been permanently protected by roofing.
The Span Rating in the trademark applies when the long panel dimension or strength axis is across supports unless the strength axis is otherwise identified.
ENGINEERED WOOD CONSTRUCTION GUIDE ■ FORM NO. E30V ■ © 2011 APA – THE ENGINEERED WOOD ASSOCIATION ■ WWW.APAWOOD.ORG
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