Waterproofing and Insulation
Waterproofing
and insulation affect a building from the roof down to the foundation. In
between the roof and foundation are walls, windows, doors, and joints.
It’s
especially critical for schools to have high-quality waterproofing and insulation
because they’re designed to perform for a long period of time. In addition,
many schools today also serve as community centers, offering such amenities as
adult education and recreational facilities after school hours, so high use
demands high quality.
Naturally,
keeping a school dry goes hand-in-hand with the facility’s long-term
performance, as most building materials either degrade or don’t perform well
once exposed to water or water vapor. Compounding the situation is that failure
often occurs in areas where it isn’t recognized until it’s well advanced, like
a leak in the roof seeping so deep that a ceiling shows a water stain or even
drips.
“It’s a
constant challenge for architects and engineers to keep buildings waterproof
and insulated,” says Will Kaly, project manager for Dayton, OH-based Lorenz
Williams, Inc.
In the Beginning
The best time
to make sure a school is waterproof and well insulated is during planning for
new construction. “It has to start very early in the process,” insists Kaly,
“all the way out to the analysis of the building location itself.”
Consider the
climate — is it wet or cold? Will it be a long and narrow facility with
southern exposure from the sun? Will it be hit with strong winds from one
direction? “These considerations may not seem very obvious,” Kaly points out,
“but they have a very large impact on the overall building systems.”
Similarly, the
interior has to be considered during planning. “What are the uses of the
interior spaces, and what do you require of them?” asks Kaly. For example, a
natatorium is a different design challenge than a library, yet you want to keep
water out of each.
Finally, give
thought to the systems you’re considering installing relative to the interior
aesthetic, finishes, and budget, as they also lend themselves to one strategy
or another for keeping water out.
Undoubtedly,
it’s more challenging to improve a school’s water seal and insulation once it’s
occupied. “In new construction, you’ve got the ability to install appropriate
systems with little delays and according to use,” Kaly points out. “It’s more
of a challenge when you have maintenance and repairs and you’re trying to keep
the facility operational.”
For example, a
leak can be a real challenge to diagnose because it’s rarely easy to access a
wall cavity or the underside of a roof. Is the water coming from a failed
joint? A flashing detail? Maybe it’s even a broken waterpipe in the plenum
above the ceiling.
Sustainability Is Here to Stay
Ensuring
schools are waterproof and insulated comes with a bonus — contributing to
sustainability. One reason is that they require less repair and maintenance, so
there are less materials going to landfills. Another is that such facilities
use less energy. “Buildings result in 48 percent of greenhouse emissions and
use up to 75 percent of energy generated at power plants,” says Kaly. “They
have a large impact on the environment, so reducing energy consumption is
important.”
The general
public is behind school districts in moving toward sustainability. Anything
administrators can do to improve a facility’s sustainability wins public
support and kudos. “We see the designers, owners, and end users coming to the
table and working collaboratively toward sustainability,” Kaly notes. “That’s a
good thing.”
Weatherizing Your Facilities
When it comes
to providing for your building envelope, attention must be paid to some
specific areas, and high-quality products must be chosen.
Roofing: Roofing insulation
can be either on top of or beneath the roofing membrane. Which is chosen will
depend on what you’re comfortable with, the region in which the facility is
built, and what the contractor is comfortable with.
Insulation is
often installed on top of the popular single-ply membrane-type roofing system.
If a leak occurs in this type system, it’s relatively easy to locate.
Insulation can
also be on the bottom of the inverted roof membrane system. “I feel it’s a
better system,” says Monica Armstrong, project manager for Atlanta-based The
Facility Group. The drawback to this system is that leaks may be more difficult
to find.
One insulation
option is polyisocyanurate, used in both new construction and renovation, and
adaptable with a variety of roof systems. The high-thermal, closed-cell foam
plastic insulation is available in a range of sizes and offers a high thermal
value per inch.
“Because
polyisocyanurate is closed cell, it has attributes that other insulation
materials don’t have,” says Jim Whitton, national sales manager for Portland,
ME-based Hunter Panels, which manufactures polyisocyanurate roof insulation
panels. As a result, the product qualifies for LEED certification credits.
Finally, when
it comes to roofing, it’s critical to prevent ponding water at penetrations
where items are mounted to the roof. An excellent method is to use a curb
that’s at least a foot high and that runs up the side and over the top of the
mounted item.
Windows: Windows are a
penetration in a building’s exterior, so it’s critical to seal the joint
between the window system and wall system. “Don’t depend just on caulking or
sealants to provide that barrier,” says Bob Gunning, AIA, project architect
with The Facility Group. “Use a flashing.”
Skylights: If you’re installing
skylights, do your research to make sure you choose a system that’s tested to
withstand wind pressure and the elements. Seal it with flashing and caulk. And,
because it’s a roof penetration, be sure it has a curb that’s high enough to
keep ponding water from getting into the joint.
Doors: Doors can be protected
from inclement weather with weatherstripping, which doesn’t reduce energy costs
so much as it increases comfort. Fortunately, it’s inexpensive and quick to
install. Gunning advises using a compressible weatherstripping around the door
frame to create a tight seal. Combine this with a sturdy sweep attached to the
bottom of the door itself and/or threshold weatherstripping.
In older
facilities, consider replacing the factory-installed weatherstripping that’s
pressed into channels in wood door frames and slipped into channels on aluminum
door frames.
Also, consider
installing steel doors, which are well known for their ability to keep out poor
weather. In addition, they’re long lasting and recyclable.
Building exteriors: Water
repellents applied to a building’s exterior substrate to create long-lasting
protection from the negative effects of weather are becoming more popular. They
can be applied to either existing or new construction, and they work to reduce
damage caused by rain, frost, and pollutants, thus decreasing maintenance
costs.
Water
repellents can be applied to a variety of surfaces — brick, concrete, natural
stone, sand limestone, split face block, and stucco/plaster.
Below-grade drainage: A sure-fire
way to keep a building waterproof is to keep below-grade water away from the
foundation. A drainage system must be well thought out during new facility
planning. When done correctly, it prevents leaky basements and structural
damage.
“A drainage
product, while not contributing to the creation of a pretty facility,” notes
Jason Covington, general manager of Wylie, TX-based CCW’s Waterproofing
Division, which manufactures a drainage system, “lends itself well to the green
movement in that it increases a building’s lifespan.”
Above-grade waterproofing: Both air and
vapor barriers are above-grade waterproofing products designed for new
construction. When properly designed and installed, they seal a building from
air and moisture.
Specifically,
a vapor barrier prevents moisture from entering the cold portions of a
building’s envelope, thus reducing the potential for condensation, which causes
both mold and building deterioration. An air barrier stops mass airflow into
and out of exterior walls, thus preventing water vapor from entering the
building envelope.
Barriers are
made in a variety of materials and come with a variety of applications. For
example, Some are a spray-on, rubberized asphalt emulsion that creates a
monolithic membrane around a cavity wall’s exterior, providing either a
polyethylene or plastic barrier. When sealing a building with either a vapor or
air barrier, be sure to seal joints between materials, as well as windows,
doors and corners.
Exterior wall systems: There is much
to choose from in today’s exterior wall systems. Manufacturers have developed
systems that offer low maintenance, energy efficiency, and durability. For
example, precast wall systems offer a wide range of cladding materials, such as
EIFS, brick, metal, and granite, and are delivered to the job site for immediate
installation.
Another
example is an insulated concrete form offering energy efficiency and
construction speed. These systems feature concrete that is sandwiched between
EPS foam and usually come in 8-ft.-long
by 18-in.-high sections. When choosing an exterior wall system, compare initial
cost vs. maintenance cost vs. energy savings of several systems to find the
best fit.
Words of Wisdom
Naturally,
choosing the right building products is important to constructing waterproof
and well-insulated schools. But the experts all agree that there’s more to the
equation.
For one thing,
getting involved early in the design process and communicating well during that
process, ensures success. “During design, let’s re-evaluate some of the
products we’re putting in or on our facilities,” says Whitton. “Ask questions,
like why did we pick that tile? Why are we leaving the gym roof exposed?”
Also, be sure
to look at long-term costs as opposed to just construction costs. Covington notes that the
cost of oil is only going to continue to rise, so administrators have to
consider products that reduce a facility’s overall energy consumption now and
in the future.
Whitton
agrees, pointing out that the money spent upfront on a higher R-value is soon
recouped through long-term energy savings.
Finally, the
experts say, once the facility is built, maintain it. “Administrators probably
hear that all the time,” says McGettigan. “And, while most educational
facilities are made of sound building materials like brick, they still require
maintenance.”
Kaly
agrees, adding that one way to accomplish high-quality maintenance is to have a
good understanding of the systems that are being put in place, as well as an
understanding of the level of performance you’re expecting and the requirements
to get that performance. “You can’t put up a school and expect it to be around
for 50 years with no maintenance,” he concludes.