Building for Weather: Balancing Cost vs. Risk|
By Reinhard Schneider
No matter what part of the world you live in, weather is an inescapable force.
While modern building techniques have evolved to help protect structures from
weather-related damage, it is impossible to make a building impenetrable and,
quite often, the pursuit of the strongest building may lead to extra initial
costs that may strain the construction budget for some building owners.
In today’s building world, how does one decide what extra precautions to take?
Certainly cold or windy regions where hail may be prevalent or especially rainy
areas such as Seattle require a specialized set of considerations.
A study by the Multi-hazard Mitigation Council
(MMC) for the Federal Emergency
Management Agency (FEMA) found that every $1 spent on loss prevention saves
society (individuals, states and communities) an average of $4 in future reduced
losses (Insurance Institute for Business and Home Safety).
But exactly where do architects and building owners draw the risk management
line when constructing a new building? Smart architects make lasting buildings
by balancing the anticipated needs of the building with budgetary realities and
appropriate product solutions to strive for long-term performance.
Protecting Interiors from Exterior Conditions
Although wind, rainstorms and hail are all different phenomena, each is
capable of causing extreme wind load, excess moisture and impact damage. The
damage these events cause to the interior of buildings is more often caused by
exterior failures that allow the elements to reach inside.
To protect buildings against weather, the best offense is a good defense. Using
a moisture-resistant fiberglass-mat gypsum panel, such as DensGlass® Sheathing
from Georgia-Pacific Gypsum, can help prevent water intrusion. Controlling
moisture entry from the outside can help prevent mold growth inside.
In areas where coastal or rain-driven flooding is a danger, there’s further need
to protect exterior walls against water damage. In August 2008, FEMA released
new guidelines1 indicating that non-paper-faced gypsum is acceptable for use in
Special Flood Hazard Areas (SFHAs). Several non-paper-faced Dens® Brand gypsum
panels from Georgia-Pacific Gypsum may be used under the new FEMA guidelines for
wall and ceiling applications in the thousands of SFHAs in the United States.
These gypsum panels are faced with fiberglass mats and feature
moisture-resistant cores to resist the effects of surface water exposure during
and after the construction cycle, thus providing resistance to subsequent mold
One potential strategy is the use of drainable dryable wall assemblies, which
use durable building materials in a unique wall configuration that allows the
wall to drain and dry out after a flood or similar event. 2 The wall is built so
the chair molding and the base molding can be removed. After removal, the gaps
behind the chair molding and the base molding provide space where the wall can
be sprayed out with a hose and left to dry.
The technique involves moving the wiring above the flood level and spraying a
2-inch-deep layer of closed-cell polyurethane foam between the studs. Leaving
the remaining space empty, the fiberglass mat drywall, which offers better
interior protection from moisture than traditional paper faced drywall, is
applied. This creates small gaps at the top and bottom of the wall that are
covered by crown molding and baseboard. If a flood occurs, the molding can be
pried off and the wall cavity can be flushed out from the top; then the water is
vacuumed up at the bottom, and fans are set to dry the wall quickly.
Averting Roof Remediation
According to the Ohio Insurance Institute, businesses in Ohio reported 3,100
claims totaling $11.1 million after a single windstorm in 20093. Higher
wind-uplift ratings on roofs may qualify for lower insurance premiums and can
help protect buildings from anticipated weather conditions. Choosing a cover
board that can add to the durability of a roofing system leads to a lower total
cost of ownership through easier maintenance and lowered insurance premiums.
For roofing, durability means more than just strength – it also means increased
protection for the people and assets inside buildings, whether it is from wind,
rain, snow or sleet. A suitable cover board, such as DensDeck® Roof Board, can
help control incidental moisture and protect against impact including damage
caused by hail.4 Choosing the right cover board will protect the investment in
your buildings, simply because the roof will be able to perform better and last
Knowledge is power in the pursuit of construction buildings suited to withstand
weather. Along with many other responsibilities, architects must also be up to
date on local weather risks and proper code requirements for building envelopes.
Deciding whether to merely meet or exceed code, however, can be a challenge best
discussed – at length – with the building’s future owner.
Flood Damage-Resistant Materials Requirements, FEMA, 2008
Please consult a qualified remediation contractor prior to use of this
strategy or any other flood remediation strategy to consider potential
contamination from flood waters and other factors. Georgia-Pacific Gypsum
does not provide flood remediation services.
Nationwide Insurance, Preventing Wind Damage
All components used in roofing systems, including DensDeck Roof Boards, may
be damaged from exposure to excess moisture and should be protected from
exposure to moisture before, during and after installation. For additional
information concerning moisture management and DensDeck Roof Boards, consult
the DensDeck technical brochure available at
About Reinhard Schneider
Reinhard Schneider is the Technical & Product Development Manager Commercial
Roofing with Georgia-Pacific Gypsum LLC , a leading manufacturer of gypsum
wallboard products in North America. A graduate of Kent State University's
School of Architecture in Kent, Ohio, he practiced architecture internationally
and in Ohio for 15 years before focusing his efforts on commercial roofing. For
more than 20 years he has been involved in the development, manufacturing,
testing and marketing of commercial roofing systems. He joined the Goodyear/Versico
roofing division in Akron, Ohio as Marketing Manager and had responsibilities
for product development and contractor training. Hundreds of contractors
attended his comprehensive, hands-on training courses each year. Reinhard then
took a position as National Sales and Marketing Manager for Clements National
Corp. / Cadillac Products in Chicago, IL, working with a number of major
membrane manufacturers to design and manufacture modified bitumen and
thermoplastic welding equipment. For the last eleven years Reinhard has been
heading up the Technical Development of DensDeck at the Georgia Pacific Corp. He
has written several articles on roofing technology that have been published in
RCI Interface, Architectural Roofing and Waterproofing and Roofing Contractor
Magazine. He is a member of RCI, AIA, RICOWI and SPRI, where he is currently a
member of the Executive Board. In recent years, he has conducted numerous
symposiums throughout the United States and Canada addressing thousands of
architects, consultants and building officials.