Page 21 - GB Building Science Ebook 2019

WEATHER-BARRIER PANELS
Specially coated panels, some with built-in insulation, have become WATER CONTROL
a popular alternative sheathing system, although conventional OSB
and house wrap still dominate the residential market. These products UMEROUS HURRICANES IN recent years have created
have their advocates. They appeal to builders, because they require more demand for extreme water management systems, as
only a minor learning curve, and accomplish two building processes a second line of defense under siding or shingles. Extreme
at once: sheathing and air sealing, saving labor. N winds can strip vinyl siding from walls, leaving only the
As with all building materials, they have both pros and cons. For weather barrier as a defense against hard-driven rain and moist air.
example, weather plays a factor anytime tape is involved. The tape
must be applied when the panels are dry, and because the panels do
not overlap and shed water naturally, taped seams represent the first
and only line of defense. If they’re not permanently sealed, water
and air could enter gaps over the long life of a building
Also, as became clear at Weatherlogic’s exhibition at Design
Week & Construction in January, when they did not flash the
bottom of their exhibit walls, if the bottoms of the panels are not
wrapped with tape and flashed with great care, and as specified,
damage can occur quite rapidly as water wicks into exposed edges
of the panels.
It should be noted that Huber Engineered Woods (HEW) has filed
a patent infringement lawsuit against LP Building Solutions for their
new Weatherlogic products, asserting that they too closely resemble
HEW’s well-known Zip System.
SELF-ADHESIVE BARRIERS
Exterior products in this category such as Henry’s (formerly
Fortifiber) VP 100 Blueskin address some of the potential weak links
in taped structural weather barriers. Blueskin, for example, allows
for an overlap that serves as a failsafe to direct water away from
panel seams, in the unlikely event of adhesive failure. Warranties
have begun to reflect growing confidence in adhesive systems, as

Blown away. Vinyl siding blasted off of walls has become an
increasingly common sight in the wake of major hurricanes,
prompting many builders to seek a bulk rain barrier. Both Tyvek
and Henry offer products that fit this niche.

reflected in the fact that Henry now offers an outstanding 15-year
warranty. The Fortifiber 1-2-3 Moisture Control System Warranty
covers both materials AND labor in the event of a product failure.
In addition, although they are strictly membranes, not structural
sheathing, self-adhesive sheets offer other labor savings as well. They
don’t have to be nailed or stapled the way some wraps do, and they
can cover numerous small leaks with a single width, (sheets range up
to 100 inches wide).
Like any exterior tape, however, the product should be applied to
a surface that is clean and dry.
SPRAY-ON SEALANTS
Another approach to weather barriers has found its niche especially
Locked Down. Fully adhesive weather barriers such as Blueskin from on commercial projects, where heavy duty water resistance is needed.
Henry Company offer a premium weather barrier with a solid 15-year Things to understand about spray-on sealants: they tend to cost
warranty. about 30 percent more than housewrap and can be applied very

BUILDING SCIENCE SPECIAL REPORT: SIX WAYS CONSTRUCTION IS CHANGING 21