Another potential problem of EIFS
is mold, which can build up in the moisture prone cavity wall. Air
is constantly exchanged between wall cavities and indoor
rooms. Air movement within a home can carry mold into the living
spaces of a dwelling.
Termites can also threaten a
synthetic stucco building. When swarming, termites look for a food
source (any cellulose product) and tend to favor moisture laden areas.
Swarming termites can enter through any crack on any level of a
building, consuming wood products. Termites infested in synthetic stucco
homes do not have to travel to the ground (their natural process) for moisture.
Because synthetic stucco holds moisture,
termite activity is more likely to infect rigid board insulation
covered with synthetic stucco.
What
level of moisture is acceptable within a wall?
When a new home is framed, the lumber
already contains a certain level of moisture (about 19%) to minimize the likelihood of
wood splitting when nailed. Once covered, the studs and
framing usually dry out to a moisture content below 8%. When
testing for moisture content in wall cavities complicated by EIFS,
the following
readings dictate the level of diligence required in remediating the
problem:
- 10-19% - Moisture is mildly evident; repairs usually consist
of coating with an acrylic sealant.
- 20-29%
- Water intrusion is occurring; the source of
penetration should be identified and corrective steps taken.
These include specific repairs in addition to application of
additional sealant.
- 30%+
- The wood is saturated and rapid decay is
eminent; EIFS in these areas should be removed
and the framing inspected closely for deterioration. Damaged areas
should be repaired/replaced.
Normally, both plywood and OSB are water resistant because they do not
delaminate or come apart when wet. However, with prolonged
exposure to moisture, OSB soaks up water like a sponge and both OSB
and plywood are vulnerable to decay under this condition. Gypsum
board is another common sheathing material used in construction.
It is less vulnerable to water damage until the protective paper
coating the gypsum eventually deteriorates from prolonged moisture
exposure. When this occurs, the glue holding the foam board
weakens and eventually fails allowing moisture penetration into the
gypsum. If this occurs, the gypsum can turn to mud in a relatively
short period of time.
Other Synthetic
Stucco Products
There are other synthetic stucco
products on the market today other than conventional EIFS. DEFS or EFS
("Direct-applied Exterior Finish Systems") and
"drainable EIFS." are systems that use cement board panels rather than styrofoam panels.
Drainable EIFS systems have drainage channels
behind the styrofoam panels. These systems are used less frequently than conventional EIFS.
Conclusion Recent data suggests that problems
with synthetic stucco are not isolated to any particular region and
reportings are becoming more frequent. The Real Estate Commission
has
determined that the presence of "exterior insulating and
finishing system" (EIFS) on a
property is a material fact item requiring disclosure to prospective
buyers. If you are uncertain whether stucco siding is EIFS, it
should be inspected by a qualified inspector.
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