Page 237 - Construction Waterproofing Handbook

4.12 CHAPTER FOUR
Synthetic stucco took a bad rap years ago from many pubic building departments and
contractors for what were supposedly numerous material and system failures. The real
cause of the failures was confirmation of the 90%/1% and 99% principles—improperly
executed terminations and transitioning (the 10% of the building envelope) were the cause
of the failures of these systems rather than the 1% chance that it was actually the water-
proofing material or envelope component itself.
EIFSs had been used very successfully in commercial construction, where professional
contractors and subcontractors would adhere to the termination and transitioning details
provided by the manufacturer. Unfortunately, the industry introduced these systems to the
residential market and did not realize that homebuilders and their subcontractors were
uninterested in something called termination and transition detailing, instead concentrat-
ing on only how fast the systems could be installed by inexperienced personnel. It was not
long before these sophisticated systems began to show leakage problems. As already doc-
umented, though, it was the improper attention to termination and transitioning details that
allowed the leakage and resulting damage to substrates and interior areas and the rise to
mold formation.
Manufacturers responded by requiring their installers to be trained in their system
application and provided details for transitioning the system into other envelope compo-
nents such as windows and doors that could be installed by their installers rather than rely-
ing on the contractor to coordinate such details with subcontractors. The manufactures also
provided better detailing for expansion joints to minimize the cracking that occurred in the
systems usually as a result of poor workmanship by untrained personnel.
Today, synthetic stucco systems make excellent building envelope finishes, and when
they are installed by trained and certified subcontractors, they provide excellent protection
against the elements, including water infiltration. Synthetic stucco is found more often
today on custom-designed homes rather than on tract-built subdivisions, the latter still pre-
ferring to use systems that are cheaper and that eliminate the need for any demanding
attention to transitioning and termination detailing. Architects who design custom homes
recognize the ability of synthetic stucco to create excellent finishes that can be manipu-
lated to produce numerous design features and aesthetic results while still providing their
customers with a well-functioning envelope.

Terminations and transitions
The importance of proper installation of transitioning and termination detailing in above-
grade construction, including residential and multifamily structures, cannot be overstated.
Water infiltration above grade in residential construction adheres strictly to the 99%/1%
and 99% principles, as discussed previously. Fortunately, for most situations, low-rise con-
struction does not encounter the weathering cycles that high-rise and large commercial
projects expect under extreme whether conditions such as hurricanes.
Local building codes also fail at providing the tools necessary to protect against the
90%/1% principle but rather emphasize the minimal requirements of individual compo-
nents and completely neglect the important transition requirement used with these code-
required components. Thus, while a window may have to withstand water infiltration
equal to 100-mph wind-driven rain, the sealant, or caulk, that is used to install the win-
dow into the envelope has to meet no requirements at all. Thus most codes are in effect