ASHRAE Journal - September 2014 - 48

COLUMN BUILDING SCIENCES

a Yank. In Canada a cold climate is
everywhere except Vancouver.§ Note
that Boston is in IECC Climate Zone
5, but New York City is not. You can
get away with stuff in NYC that you
cannot in Boston.
So let's say you are in a place that
you should worry about freezethaw? Now what? OK, now we look
at concentration of rainwater. This
takes judgment and experience.
Relax. We can do this. Old architects really got it right. We just need
to remind the youngsters. One of
my favorite all-time buildings is
at my alma mater, the University
of Toronto (Photo 1). Look at all the
drip edges-at roof edges, at window
openings, between floors. Notice
that they are working. How can you
tell? No stains. Look at this building
carefully because it is an example of
"what is good."
You want to see stuff that is not
good? Look at Photo 2. Pretty obvious, eh? How about Photo 3 and
Photo 4? Windows are places where
water is concentrated. Why?
Well, large expanses of glass don't
absorb water. Water runs down
them and ends up at corners that
are typically "inset" with surfaces
that don't slope. It gets worse, the
windows themselves leak and act
as "syringes" for "liquid crack" that
inject poison into the body of an
assembly.# The openings need drip
edges, end dams, back dams and
slopes and kerfs. You want to know
how to do it right? Go to Ireland
and look at real old stuff (Photo 5)
and not-so-old stuff but still old
(Photo 6).
§It is hard to not say something here, but I am trying this self-

restraint thing out to see how it works.
#The self-restraint did not last long. Over the top? Yup, but
trying to relate to the cable audience.
48

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PHOTO 8 (LEFT) All-Time Favorite. An old brick factory converted to seniors housing with "good brick" on the
street side. All the drips, the flashings, the end dams, the back dams, the slopes, the kerfs, the parapet caps
were added as unobtrusively as possible. The street side brick shown here was cleaned. Notice the fabulous
parapet that was added with the drip cap. PHOTO 9 (RIGHT) Back Side Brick. Brick on the back side was stuccoed
with a polymer cement slurry. The thin vapor open hydrophobic cementious layer allows the texture of the brick
joints to show through. It is real important that the vapor transmission of the cementious layer is greater than 10
perms. If not, the coating will bubble and blister and peel. An even more conservative approach is the European
one-just add a direct applied traditional stucco and forgo the historic tax credit.

FIGURE 4 Basement Foundation Retrofit. This works everywhere (see "Small Sacrifices," ASHRAE Journal, July 2007).
This will not work with air permeable insulation that is moisture sensitive. No fiberglass or cellulose below grade in
this type of assembly. You can add fiberglass or cellulose to the interior of the spray foam in this assembly, but not
instead of the spray foam in this assembly. Further note that we are talking the high-density closed cell stuff.

SEPTEM BER 2014

ASHRAE Journal - September 2014

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