Hard Coat Stucco Inspections
The History of Synthetic Stucco
Synthetic Stucco, also known as EIFS (Exterior Insulated Finish System), was first
used in Europe after the end of World War II. The product was first installed on commercial buildings in Germany.
Synthetic stucco eventually made its way over to the United States.
As in Europe, the early installations were on commercial properties. In the 1980’s, architects and builders began experimenting
with the idea of using synthetic stucco on residential homes.
What is Synthetic Stucco?
Synthetic stucco installation begins with attaching 2’ X 4’ EPS foam panels to the plywood
sheathing of the structure. A fiberglass mesh is attached to the foam. The stucco, which is an acrylic, rubber based product,
is applied in one or two coats, and the final product is typically 1/16th to 1/8th inch thick. In comparison, hardcoat stucco
installed over wood strips, known as lath, or over metal lath, does not have the foam underlayment, and is usually 3/4"
to 1 inch thick.
Synthetic Stucco Used?
The product was
touted as the "Exterior Cladding of the Future". Benefits included the ease and low cost to install. The EPS foam
installed behind the stucco provided additional insulation benefits. The finish color is consistent throughout the stucco,
making it, in theory, low maintenance. Architects favored the product because you could create interesting design features
and details, adding to the curb appeal of homes with synthetic stucco cladding.
What are the problems with EIFS?
Synthetic stucco was meant to be a barrier system, meaning it was not intended for
water to get behind the stucco. Once water got behind the stucco, the water was trapped, causing wood rot to the wood framing
and sheathing of the home, as well as mold and mildew.
the early 1990’s, problems were discovered on homes with EIFS located in Wilmington, North Carolina. Removal of the
stucco revealed extensive structural damage to the homes as a result of moisture intrusion behind the stucco. Local building
officials called in the builders, architects, and stucco manufacturers to evaluate the problem.
The examination of the home revealed moisture was intruding behind the stucco cladding,
as a result of poor design and installation. Installation defects include failure to install proper window, door, and kick-out
flashings, and leaking windows. In addition to the moisture related problems, it was discovered that the foam behind the stucco,
when installed at or below grade, was conductive to termite and fire ant infestation.
As a result of problems discovered with synthetic stucco clad homes, inspection and testing
protocols were created. The Exterior Design Institute, located in Virginia, was formed to educate and train independent, third
party, EIFS inspectors.
Synthetic Stucco Inspection
intrusion inspection on a home with synthetic stucco is a combination of a visual inspection, and moisture detection using
moisture meters designed specifically for this purpose.
visual inspection accesses the installation of the stucco. The inspector verifies whether flashings are properly installed.
The stucco is checked for any signs of damage, cracking, and delaminating. The inspector will determine if the stucco system
terminates above or below grade. The windows and doors, porches and decks, and utility penetrations are carefully examined.
The home is then scanned for moisture using a non-invasive meter,
typically a Tramex Wet Wall Scanner. This type of meter will scan up to 3 inches behind the stucco for any signs of moisture.
The drawback to this type of meter is that false positives may occur as a result of metal installed behind the stucco, such
as metal studs, electrical wiring, and plumbing piping. Inspection protocols require that specific areas be tested using a
probe meter. With permission from the homeowner, two holes are drilled in each probe location. The probe meter will provide
readings of the actual moisture content of the sheathing behind the stucco. Moisture readings below 14% are considered low,
between 14 and 18% medium, and readings above 18% high. Moisture levels above 25% for an extended period are conducive to
rot to the wood framing and sheathing, as well as mold and mildew.
All readings are recorded, and digital color photos are taken to document the condition of the system, including
components installed correctly and incorrectly. A computer report is compiled from this data.
Why is it important that my stucco inspector not do any repair work?