can forestall vapor from traveling through the wall
to a temperature where it would condense and
help keep the enclosure dry. An opposite situation
arises in a cool climate where winter air is
humidified and warm interior air escapes through
the walls to the exterior. In that situation, a vapor
barrier installed on the warm inside of the wall
can guard against the formation of condensation
in the wall cavity where spalling and
efflorescence could occur on the brick veneer.
Proper location is paramount as a vapor barrier
positioned in the wrong location can actually
contribute to condensation within the building.
Ultimately, the strategy behind a vapor barrier
is to stop moisture from reaching a spot in the
building where it can condense. Another vapor
management strategy would focus on making
sure the wall is completely vapored permeable
so that condensation vapor travels through the
wall to the exterior where it can evaporate into
the environment and dry quickly before moisture
accumulates.
MASONRY DESIGN: What tools are available
to help designers, specifiers, and contractors
choose the right product?
Tiffany Coppock: The variety of products can be
overwhelming and is one reason Owens Corning
has a building science team devoted to analyzing
moisture throughout the enclosure. Basic
dewpoint analysis allows us to look at how
moisture travels through a wall under given
circumstances including temperature analysis,
relative humidity, and specific wall assembly. This
data can provide designers with direction to guide
the selection of materials and location of the
product within the enclosure in a very quick
analysis. We can also provide advanced WUFI
analysis for mission-critical buildings such as
library archives, laboratories, and healthcare
facility MRI suites where the environment must
be tightly controlled and we cannot afford to have
a performance failure. We combine historical
weather data, material analysis, and anticipated
drying times to lend an even higher degree of
guidance to inform material selection and
placement within the enclosure.
48 | Masonry Design
MASONRY DESIGN: From a contractor’s
perspective, what resources are available to help
inform the selection of the right air, water, and
vapor barrier product?
Tiffany Coppock: The number of choices for
stopping air, water, and vapor has definitely made
the selection process more challenging. Today,
a large number of products on the market seem
to advertise as an air barrier. There’s a running
joke in the community that peanut butter actually
makes a great air barrier (passing ASTM E2357),
albeit bringing pest control issues! But when
making a choice, it’s key to consider which
product is going to deliver longevity and be
compatible with other components in the system.
Familiarity with a product and how it is installed
can also support the choice of barrier product, as
well as access to the type of equipment
necessary to apply the barrier to the substrate.
Contractors shouldn’t hesitate to ask a product’s
manufacturer to come out and provide training on
installation as well as guidelines for various steps
such as fastening patterns and detailing. Another
great resource is the Air Barrier
Association of America (ABAA). ABAA provides
training for various assembly types (peel and
stick, rigid board, etc.) and most recently wall
systems such as the Owens Corning Cavity
Complete® system. Certification includes
classroom instruction, on-site demonstrations,
written exams, and practical exams, along with a
card noting certification. Increasingly, we are
seeing more specifications require installation
by an ABAA certified installer along with ABAA
certified projects. Such certification provides a
third-party audit that speaks to a contractor’s
knowledge and demonstrated proficiency with a
building enclosure product.
MASONRY DESIGN: From an installation
perspective, what are some best practices for
installing air and water barriers?
Tiffany Coppock: The installation practices
actually begin in the design development stage.
It’s a good idea to gather drawing sets, stick a
pen on the air and water vapor and actually trace
all the way around the building. Assuring
continuity is critical AND if the pen has to be