Architectural Record 2015-04

158 EFFECTIVE AND AFFORDABLE HOUSE WRAPS EDUCATIONAL-ADVERTISEMENT
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to cooking emit up to 6 gallons of moisture
a week—that water has to go somewhere. If
the house wrap does not breathe properly, the
moisture will escape through the walls, and
enter the wall cavity where it is stopped and
trapped if the house wrap is non-breathable,
the result of course being the potential for
degradation of many commercial insulation
products as well as for rot, mold, and eventually,
structural failure.
Products fabricated in the form of clothlike,
non-woven water-resistant barriers use
a patterned, grooved, dimpled, or otherwise
textured surface to create a breathable barrier
and improve water drainage within the wall.
Rather than lie flat against the siding, the
vertically textured material forms a thin air
space that acts to encourage the channeling of
any liquid that reaches the siding of the home to
quickly drain out to the ground. These textured
house wraps have achieved impressive drainage
rates, with some demonstrating a 98 percent
efficiency in liquid drainage.
As can be seen in the above comparative
illustration in which house wrap is attached to
oriented strand board sheathing on top of 2x
stud framing, textured house wrap is superior
to non-textured in terms of water drainage. The
textured material channels water away from the
wall structures to the ground, while water vapor
condenses on non-textured house wrap and
runs down, pooling on top of the siding or in
Photo courtesy of Kimberly-Clark
Next-generation house wraps resist water and
air intrusion into the structure and allow water
vapor to escape from the wall cavity, leading
to more energy-efficient, sustainable homes.
Images courtesy of Kimberly-Clark
Textured house wrap (figure on left) protects homes by channeling water away from wall
structures and to the ground. On non-textured house wrap (figure on right), water vapor
condenses on house wrap and runs down, pooling on top of the siding or in the folds and
wrinkles of the wrap. This moisture can lead to mold and rot of the wall assembly.
the folds and wrinkles of the wrap. This
trapped moisture can lead to mold and rot
of the wall assembly.
While this level of performance may signal
a product that is prohibitively expensive, that is
not the case. Textured house wrap can be a midprice
product when the manufacturer has a firm
control of costs, particularly when the product is
fabricated in the manufacturer’s own mills—an
arrangement with favorable implications not
only for pricing but for quality control as well.
Foam Sheathing and House Wrap
Foam sheathing is not an air barrier or a
weather barrier. While foam sheathing may be
an adequate, low-cost method for achieving the
R-values required by the 2012 IECC, because
it does not provide an effective water-resistant
barrier, it fails to protect the structure in a
comprehensive manner. Even when properly
installed and taped, foam sheathing lacks the
shingling effect necessary to keep water from
seeping through the edges of the tape and into
wall assemblies. Once those wall assemblies
get wet, the ambient humidity both inside and
outside the structure can make them tough to
get dry, resulting in rot, mold, and eventual
structural failure—all problems that have
resulted in skyrocketing insurance claims that
continue to plague builders. Some consider it
best practice to install an effective WRB that
can provide weatherization and breathability
benefits that help maintain the as-constructed
R-value of the home insulation. The right,
properly installed house wrap can provide a
superior air barrier to foam sheathing by itself,
which can expand and contract in the heat and
cold, causing tape seams to fail, which allows the
air barrier to be broken.
As the building community becomes more
aware of the advantages, the use of house wraps
will increase in the coming years. Driven by
building codes, regulations governing building
envelope systems, and the move to construct
energy-efficient homes and upgrade existing
insulation systems, house wraps in fact are
expected to see a surge in growth globally,
according to consulting firm Frost & Sullivan, in
its recent report entitled “Analysis of the Global
House Wraps Market.” The firm found that the
house wraps market earned revenues of $696.4
million in 2013 and estimates this to reach $1.05
billion in 2018, with user preference for the nonperforated
house wraps projected to increase
during the forecast period. Manufacturers
providing a wide range of products with
optimum price-performance stand to gain as
do those with “efficient after-sales services,
including on-site support, extended warranty
programs, and product workshops will provide
opportunities for market participants to speed
up customer acquisition.” 3 The study goes on
to state that “the energy to manufacture house
wrap for a single house is only 1.2 to 1.8 million
Btu depending on the type of polyolefin used,”
and that “compared to the energy savings
resulting from the application of house wrap,
the average ‘pay back’ period ranges from only
7 to 54 days.”
See endnotes in the online version of this article.
Continues at ce.architecturalrecord.com
Kimberly-Clark Corporation is an indispensable part of life for people in more than 175 countries with its wellknown
brands such as Kleenex, Scott, Huggies, Pull-Ups, Kotex, and Depend. Kimberly-Clark is now drawing on its
expertise in the development and manufacturing of nonwoven, breathable materials to enter the building materials
industry with BLOCK-IT* House Wrap. www.BLOCK-IT.com
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