TACOMA, Wash., July 18 /PRNewswire/ -- The six-month hurricane season
is well underway and how your home weathers the onslaught will depend in
large measure on how well your building envelope performs. Building
envelopes (walls and roof) that remain intact during high wind events are
less likely to experience catastrophic failure than those with breeched
windows, doors and roof elements. APA - The Engineered Wood Association
offers several recommendations to help builders and homeowners improve
their structure's survival odds.
"The first measure of defense when building in high wind regions is to
fully sheath the home with wood structural panels. Using plywood or
oriented strand board (OSB) walls is the best-known way to strengthen wood
frame buildings," said Bryan Readling, a staff engineer with APA's Field
Services Division. Flying debris is a significant cause of damage with
hurricanes and wood walls are a great defense against airborne projectiles.
As part of several damage assessment teams investigating tornado and
hurricane aftermath, Readling has noted that fully sheathed wood homes
experience far less debris penetration. "In many instances the wood panel
sheathing helped keep the structure intact," said Readling.
The second area of defense concerns the roof. APA recently updated Roof
Sheathing Fastening Schedules for Wind Uplift, which provides recommended
nailing schedules for wood structural panel sheathing -- plywood or
oriented strand board (OSB). Developed through engineering analysis and
full-scale laboratory testing of wet and dry panel specimens, the schedules
give nailing recommendations for 90 mph, 120 mph and 150 mph wind
conditions (3-second gust). The 150 mph schedules are appropriate for most
hurricane oceanline regions in the Atlantic and Gulf Coast regions. Another
important consideration is the wood species of the roof framing members.
According to APA research, more dense species such as Douglas-fir or
southern pine provide greater nail withdrawal resistance and significantly
improve the performance of the sheathing nailing.
During high wind events, a home's garage opening is another vulnerable
spot where breeches may occur. "We noted inadequate lateral capacity in
walls adjacent to the garage opening as another mechanism which triggers
large-scale failure," said Readling. Fully sheathed homes can take
advantage of APA's prescriptive narrow garage wall details that permit
16-inch walls adjacent to the garage opening (International Residential
Code 2006 IRC 602.10.5). APA's Narrow Walls That Work includes details for
building over permanent foundations and raised wood floors. This
site-built, bracing solution may be used in wind zones up to 109 mph.
Keeping the windows intact under a barrage of windborne debris is
imperative to a home's survival. Wood structural panels provide an
effective barrier to both flying debris and the sudden pressure changes
that result from minor breeches in the building envelope. APA provides two
alternatives for builders and homeowners in the 18-page Hurricane Shutter
Designs. The first approach provides code minimum requirements for using
wood structural panels as shutters. The second approach offers five
designs, which provide additional strength and stiffness beyond code
requirements. These designs include several attachment options for use with
masonry block and wood framed structures.
To order publications, (minimum order $4.00) request:
Roof Sheathing Fastening Schedules for Wind Uplift, form # T325, single
copy $.50
Narrow Walls That Work, form #D420, free pdf download only
http://www.apawood.org
Hurricane Shutter Designs, form #T450, free pdf download only
http://www.apawood.org
-- Mail: APA -- The Engineered Wood Association, Publications Department,
7011 S. 19th, Tacoma, Washington, 98466
-- Email: lit.orders@apawood.org
-- Fax: 253-565-7265
-- Web: http://www.apawood.org/publications
APA - The Engineered Wood Association (formerly American Plywood
Association) is a nonprofit trade association whose domestic and
international members produce a variety of engineered wood products. APA's
primary functions are quality inspection and testing, applied research and
product promotion.
SOURCE APA - The Engineered Wood Association
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Related links:
http://www.apawood.org
CONTACT:
Kevin Hayes of APA - The Engineered Wood
Association, +1-253-620-7445, or Kevin.Hayes@apawood.org
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