I recently went to a talk by Joe Lstiburek of Building Science Corporation
of Massachusetts.  He is an expert in moisture control and is not a fan of
either Tyvek or EIFS in their most commonly applied uses.  His two adages
are simply 1)  "If you can't control rain, nothing else matters."  and 2)
"Drain the rain on the plain"  (or to be verbose:  make sure you have a
continuos vertical to horizontal drainage plain).  His first assumption is:
"All windows leak, all walls leak."
    Interestingly, most of the problems we looked at in his case studies of
EIFS were in buildings less than a year old and in warmer climates.
Typically the problem was caused by two design and construction flaws:  a)
leaky or incorrectly spec'd cooling duct work caused cooling of walls where
it was not intended and b) (following manufacturer's recommendations)
fiberglass insulation was installed with its facing to the inside of the
structure, additionally vynil wall paper was installed over interior sheet
rock:  thus creating a vapor barrier on both sides of the wall, hence an
assembly which can neither dry to the inside or outside.
    His best remedies for buildings is to create predictable and
controllable pressure systems in the structure so that a building either
"sucks" or "blows": northerners "suck" and dry to the outside and
southerners "blow" dry to the inside.  Being a Canadian he did allow that in
Washington D.C. buildings can "suck" and "blow".  This explains the
geographic choice for our capital.
Best,
Leland

-----Original Message-----
From: Ken Follett <[log in to unmask]>
To: [log in to unmask]
<[log in to unmask]>
Date: Thursday, May 27, 1999 1:24 PM
Subject: EIFS Appraisal


>EIFS Appraisal
>
>"Using EIFS siding assumes that moisture will not penetrate to the
substrate.
>In practice, however, water does penetrate, principally at the edges of
wall
>openings (e.g., doors, windows, decks, roof intersections), through jambs
and
>sills of window frames, and through cracks or chips in the siding itself.
It
>appears that even high-quality window frames allow moisture to penetrate
the
>siding, which is then contained between the surface of the EIFS system and
>the underlying wood, gypsum, or OSB intermediate sheathing and the stud
wall.
>Even a small crack in the EIFS surface, resulting from hail damage or
>wind-blown debris, provides a moisture entry pathway, and there is
>unfortunately no consensus test method in the United States for EIFS impact
>resistance. The EIFS industry itself admits that if "the likelihood of
impact
>damage is very high, it is probably a good idea not to use EIFS at these
>locations.""
>
>_The Performance of Exterior Insulation Finish Systems and Property Value_,
>John A. Kilpatrick, Douglas C. Brown, MAI, and Ronald C. Rogers, PhD; The
>Appraisal Journal, January 1999.
>
>The article, written for property appraisers, states that owners of EIFS
clad
>buildings face significant potential value losses due to 1) present value
of
>future repair work, 2) present value of future increased maintenance cost
and
>3) stigma. The stigma factor is difficult to quantify and has to do with
the
>perceived value of the properties.
>
>Distribution of use and EIFS stigma differs geographically. Ratio of
>distribution varies geographically between residential and commercial
>structures. Use of EIFS in America and Europe is significantly different.
In
>America application is mainly to stud walls whereas European application of
>EIFS is mainly over solid masonry. It is difficult to make objective
>comparisons between EIFS use, durability or perception in the two markets.
>
>In Florida an estimated 25% of 100,000 homes built annually  are built with
>EIFS. Significant information considering if the industry lacks data on
>impact resistance.
>
>Is EIFS really a better a better alternative than the aluminum trailer park
>in the flood plain? I'll regress to the three little pigs and build with
>brick and stone.
>
>][<en Follett
>