A few good words about EIFS. During the mid-80's I practiced architecture
in France, and EIF--applied to masonry buildings, usually for low-rise
apartment and office buildings--was considered tried-and-true. It works
very well on masonry, usually block, especially with high quality windows.
The dentability depends on the coating thickness and use (or not) of
reinforcement. It works poorly on frame construction because of the
inability of frame construction, especially the gypsum or wood product
sheathing, to accommodate the amounts of water that get in at details,
flashings, windows, etc. In areas with low rainfall, or with the newer
"drainage plane" systems, the water performance moves up to the "not too
bad" range. EIFS got its worst raps in Wilmington NC and Vancouver BC, both
locations needing special care in rainwater discharge. In Vancouver,
balcony projections were the worst site of water entry.

What has always been appealing about EIFS is that it solves the
"condensation" problem, all by itself, if the source of water vapor is
indoors. Try running the numbers in ASHRAE Handbook of Fundamentals. It
solves the problem the same way an insulated low-slope roofing system does
or a SIPS panel, by keeping the outside face of any building cavity
relatively warm in cold weather.  EIFS should probably be installed without
polyethylene in the wall, to help dry out any rainwater that does get in,
but try convincing a building inspector of that.

Application of EIFS to frame construction has taken a long slow learning
curve, very painful for the high-end systems such as Sto and USG and
others. I bet it'll turn out in the end to be a product with decent
moisture performance. I'm reluctant to recommend EIFS for fire reasons. The
recipe for napalm is styrene plus benzene. Architects like EIFS because
it's full-size foamcore. Sure, it's crap. Unused, straight-grained,
first-growth redwood isn't. Which do we pick?

Bill Rose (lurk no longer)


At 02:15 PM 3/24/99 EST, you wrote:
>In a message dated 3/24/99 12:36:43 PM Eastern Standard Time, [log in to unmask]
>writes:
>
><<  my EIFS experience is from investigating a botched job, for
> which we were never able to identify any decent details >>
>
>As far back as I can recall no information regarding vapor transmission from
>interior spaces has been dealt with in EIFS literature. The insulating
barrier
>is not permeable on the exterior, but the stucco materials are. Condensation
>will occur on the back face of the crap and it doesn't matter how well you
>apply sealant to the exterior face of the stuff, moisture is going to enter
>the system. No performance criteria has been developed for interior vapor
>barriers when used with the stuff as far as I know, but I'd love to be proven
>wrong. The ASHRAE handbook makes predictions about how much vapor can be
>anticipated through an installed system, but otherwise provides no
>information. I also just love the idea of applying a material, to the
exterior
>of a building, which can be rendered useless following a collision with a
>tricycle.
>
>Twybil
>
>

---------------
William B. Rose
phone: 217 333 4698,    fax: 217 244 2204
http://www.arch.uiuc.edu/brc/billrose.htm