Proper installation methods for synthetic stucco on buildings
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Discussion of the inspection, diagnosis, repair, and proper installation of synthetic stucco EIFS systems.
EIFS is an abbreviation for "Exterior Insulation and Finish Systems" or "barrier", a synthetic stucco material which
is usually applied over a system of solid foam insulation board and synthetic fabrics to form a stucco building exterior
surface.
There have been substantial building failures and costly damage at many EIFS
covered buildings, primarily because the EIFS-covered building exterior may leak into the building walls but the foam insulation
used beneath this stucco method may not allow moisture to escape from building cavities.
In a nutshell, leaks into the structure of an EIFS-covered building can cause major mold, rot, and structural damage because water leaks into the structure from
installation defects (very common), holes, or damaged siding.
EIFS synthetic stucco product manufacturers provide detailed installation guides that should be meticulously followed by builders. EIFS manufacturers state that if their materials are installed according to
their specifications there will not be problems with this synthetic stucco method.
But we have rarely found a residential building at which the demanding and
detailed product specifications have been followed during installation, and in our OPINION, the specifications may be just too demanding for many residential EIFS installers.
EIFS siding material has been the subject of failures and litigation.
The photographs above are of an EIFS building exterior showing the attractive EIFS finish in the left photo and
a typical wall leak at an improperly installed window sill in the right-hand photo. Further invasive inspection found rot and damage
in building walls at multiple locations where penetrations or absent flashing or caulking had led to leaks.
Our photo (left) shows an inspection point on a recently-constructed EIFS sided building. While the wall looked great from outside, inside the building. this wall cavity was wet and moldy. We were surprised to find wind-blown leaks just under the eaves of the soffit overhangs where the manufacturer-recommended backer rod and sealant had been omitted..
At another EIFS building we investigated and one which was in litigation, the EIFS installation contractor defended a defective EIFS
installation (no caulking, no sealants, no flashing) by arguing that the prime contractor was responsible for those details and that his
contract excluded those details.
He was "just
hired to apply the stucco system". In view of the fact that "application" of the particular manufacturer's stucco system called for
numerous sealing details, not one of which was followed, this was a ridiculous argument. Damages were substantial.
EIFS, Synthetic Stucco, Dryvit, Sto wall type system failure investigations, EIFS leaks, building rot from siding leaks,
EIFS defects-caused mold damage, EIFS siding inspection and repair methods are discussed at the links to articles, attorneys, associations, and product manufacturers
listed at this website.
When originally imported from Europe to the United
States in the 1970s, most exterior insulation and finish systems
(EIFS) were “barrier” type systems. They were designed
to create a waterproof exterior skin consisting of a
thin layer of acrylic polymer-based synthetic stucco directly
applied to foam insulation.
The expanded polystyrene
(EPS) foam was glued to the building’s sheathing.
A layer of fiberglass cloth embedded in the synthetic
stucco provided reinforcement, and a thin acrylic finish
coat added color and texture.
With the EPS glued directly to the sheathing, there
was no place for building paper or conventional flashings
at penetrations. Openings, joints, and penetrations relied
on caulks and sealants for waterproofing. With no backup
waterproofing or drainage layer, there was little margin for
error.
While these systems performed adequately in Europe
for nearly 25 years, the United States version had thinner
base coats and lower polymer content, creating a weaker
skin. Also, workmanship in the United States was often inferior
due to lack of applicator training and quality-control
programs.
When water leaked into these systems through
failed caulk joints, cracks in the stucco skin, or through
the window frames themselves, it wet the foam insulation,
sheathing, and sometimes the structural framework.
The water running down the building interior wall (photo above left) was traced to omission of the manufacturer-specified sealant methods at the top of the building exterior wall. Wind-blown rain entered the wall top just below the soffit overhang, wet the wall interior cavity, and finally appeared on the foundation walls below.
At our photo guide to some common leak points found on EIFS clad buildings SIDING EIFS WALL LEAK POINTS, one of our our EIFS leak point photographs shows a leaky window detail at an EIFS-clad building in New York.
This
installation error in turn led to more sealant failures and cracking of the surface
and additional leakage. The EPS foam acted like a
sponge, trapping water against the building, and the nonporous
polymer coatings retarded drying. In many cases
the leakage and resulting decay was extensive, resulting in
widespread property damage and litigation.
To continue reading about how EIFS wall system manufacturers addressed these concerns, see STUCCO EIFS DRAINAGE SYSTEMS.
If you are an EIFS manufacturer, installer, or EIFS inspector, contact us at LINK EXCHANGE to add listings - there is no fee.
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Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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Class Action Settlement for Senergy and Thoro brands of EIFS was completed the Superior Court of the State of North Carolina, Hanover County
"Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
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