What is Stucco and related issues
With Urea Formaldehyde Foam Insulation, most of
us pronounce it "you-fee" but some insisted on
"u-fee." In Canada "e-fiss" appears to be the
preferred pronunciation for EIFS.
So now we can say it, but what is EIFS and why do
we care? EIFS stands for Exterior Insulating and
Finishing Systems. It is sometimes referred to as
Synthetic Stucco. Its use increased sharply in the
1990s. In North America about 300, 000 homes have an
EIFS exterior.
We care because EIFS has been connected to
concealed rot in wall cavities.
What Is Happening
Rain water appears to be getting into the wall
systems through imperfections in the stucco. These
include joints around windows and doors and
penetrations from railings, wiring, plumbing, vents,
etc. Once water gets behind the system it gets
trapped, leading to mold, mildew and rot of the
sheathing, studs, flooring and other framing
members. EIFS houses often look good until sections
of the wall are removed revealing concealed damage.
The damage can take place within the first few years
of the home's life.
As most of the damage has been found in houses in
coastal areas, some have suggested that condensation
is a problem; however, since the most severe damage
seems to show up around wall penetrations,
condensation does not appear to be the culprit. The
worst damage is often found below and beside
windows.
Conclusions
So far we know that
areas of high rain fall, and particularly areas with
rain accompanied by wind, result in houses with the
most damage. Homes which have no roof overhang or
very small overhang or many penetrations through the
wall systems are also at risk.
Unfortunately, a
visual inspection cannot tell the whole story, and
until invasive testing becomes standardized and
sufficient data becomes available for our area,
concealed damage in synthetic stucco houses will
remain a question mark.
There is no doubt
that south of the border, this has become a major
issue. This, however, does not necessarily translate
into a Canadian issue.
Carson Dunlop
Reports have traditionally described problems but
then provided economical solutions. Unfortunately,
the jury is still out on EIFS homes in Canada.
What Exactly Is It?
There are many different systems offered by
various manufacturers, but in general EIFS wall
systems consist of a wood frame wall covered with a
sheathing such as plywood, or even gypsum board.
Plastic foam insulation boards are glued or fastened
to the sheathing. A 1/16- to 1/4- inch-thick base
coat is troweled on to the insulation. A glass fiber
reinforcing mesh is imbedded in the base coat.
Finally, a finished coat is sprayed, troweled or
rolled on. This finish coat provides the color and
texture.
Many installations have no building paper or
housewrap behind the stucco to act as a backup
material.
Solutions
There is little that can be done on existing
systems short of re-siding or paying fanatical
attention to keeping the water out. Caulking and
flashing maintenance should be a high priority for
people with synthetic stucco houses.
In the very newest installations, contractors are
using building paper or housewrap behind the
insulation to protect the sheathing. In addition,
the newest installations are designed with a
drainage system behind the insulation to allow any
water which does get in, to drain out. This is not
unlike the drainage system found in a brick veneer
home. These improvements
should work but only if they are well constructed.
