Masonry Design | 49
picked up at any point, it’s a good indication that
the particular area needs to be closely analyzed
for potential air and water leakage.
Water barriers must be continuous and
contractors should evaluate continuity when they
receive the drawing set. Contractors should also
look for compatibility and ensure substrates are
correct. For example, if you’re applying a
barrier to a CMU wall, you want to make sure
there aren’t a lot of mortar fins that could
interfere with the consistent application of the
product. Frequent meetings with team members
and sub-contractors can make sure everyone
understands how important the materials are to
the finished building. Protecting the air barrier
after it is installed is imperative. For example, if
a product is not supposed to be exposed to UV
light over a period of time, installation should
be timed appropriately. Be sure to protect the
product from any freezing, thawing, vehicular or
mechanical damage that could occur, as damage
is a primary reason for contractor callbacks. As a
matter of fact, the ability to repair damage should
also factor into product selection- some
membranes are easier to restore to a continuous
state than others.
MASONRY DESIGN: What are some questions
or considerations to take into account when
selecting an air and water barrier product?
Tiffany Coppock: There are many factors to
consider, but here are some big questions to ask.
First, is it code compliant? Make sure the product
complies with all specifications and codes before
placing the product order. Next, consider the
installation procedures for applying the air and
water barrier to the wall and protecting its
following installation. Also, know the minimum
and maximum temperature for application,
humidity levels, etc. Of course, the cost is always
a factor. Consider not just the cost of the
product but the labor cost associated and how
that cost may vary according to geographic
region. In some regions of the country, one
product may be more expensive to purchase but
deliver a lower overall installation cost based on
labor rates.
It sounds obvious, but be sure the roof is installed
before applying the air and water barrier. I’ve
been in buildings where water was ankle deep
and the air barrier was already applied. These
barriers are not intended for immersion in water.
The walls will only hold water for so long and it’s
important to protect the area from moisture
before and following application.
Consider how the shape of the structure lends
itself to various methods of application. I’ve
worked on a number of sphere shaped buildings
and their unique geometry often makes a fluid
applied membrane the simplest type of barrier to
install.
It should be noted that while these barrier
products are dealing with air and water
movement throughout the enclosure, they must
also comply with NFPA 285 in most commercial
situations. The Owens Corning® Enclosure
Solutions NFPA identifies almost 75 different
products categorized by vapor permeable or
impermeable and application method that comply
with NFPA 285 and provides details for helping
select a product that works with the building
design and wall assembly.
And finally, don’t hesitate to ask for help. The
Owens Corning Building Science Center offers
moisture analysis, NFPA 285 assembly design
resources, and regional guidance through all
phases of design.