EIFSFACTS.ORG
The Real Facts About EIFS
- Letter to Macon Lowe -
[Editor's Note: The following letter was written by a Virginia home-owner who has been deeply involved in the EIFS problems for a long time. In fact, her involvement predates my own. She has done more hard-core research into the EIFS problems than any other individual I know of.]
December 20, 1999
Mr. Macon Lowe
President and Chief Executive Officer
Sto Corp.
3800 Camp Creek Parkway
Building 1400, Suite 120
Atlanta, GA 30331
Re: Sto Corp. Web Site
Dear Mr. Lowe,
I am writing to you about two articles posted on your corporation’s web site that I believe are, at the minimum, misleading.
The first is entitled “News Release-EIFS survives water torture. Warnock Hersey Canadian test demonstrates effective water penetration resistance of standard EIFS details.” This “News Release” which has been featured prominently on your company’s web site for some time, states in part:
“What does it take to prove that an EIFS, properly integrated into construction, provides as effective protection from water intrusion as any other cladding system, and from a design standpoint, in many ways superior?
Amid continuing misunderstanding about the ability of EIFS to provide protection from water entry, Sto, the leading international EIFS manufacturer, took on the challenge. The Atlanta-based company commissioned a series of rigorous tests involving, among other things, blasting water against a test wall with a DC-3 airplane engine. The intent of the program was to demonstrate conclusively that EIFS detailing, properly installed would not permit water intrusion into the wall cavity.
The company commissioned the internationally respected testing agency, Intertek (Warnock Hersey), at their Coquitlam test site near Vancouver, British Columbia.
Our instructions to Warnock Hersey were to test as needed for BOCA requirements,” says John Edgar, Sto’s Technical Services Manager. “We also asked them to test with dynamic wind loading, using the DC3 engine, to evaluate the performance of details and the two stage joints, which were of interest to CMHC (Canada Mortgage and Housing Corporation).”
At first glance, results from this testing certainly appear to support the long-held public position of your corporation as well as the EIFS trade association, EIMA, that “effective protection from water intrusion” can be achieved with the use of “standard EIFS details”.
Omitted from this carefully worded document however, is any reference to the fact that the type of joint used in this demonstration, a two-stage joint, is not the type of joint that is used in a “typical” barrier EIFS installation. In fact, all documents that I have been able to obtain, including those published and distributed by Sto have always specified the use of a single-stage (North American) joint with the installation of these systems.
As the number of EIFS-clad structures known to be affected by water intrusion continues to mount in Canada (and the U.S.), it is certainly understandable that a government agency such as CMHC, would be interested in any testing of this product. Curiously missing from this article however was any mention of the research conducted several years ago by a Canadian Government agency at the request of another EIFS manufacturer. Testing for U.S. Gypsum at NRC-IRC proved conclusively that a single-stage joint correctly installed with backer rod and sealant, failed to prevent water intrusion. Unlike other claddings that recognize water intrusion in construction is normal and provide a means for its escape, the installation of a barrier EIFSystem depends entirely on the face-sealed approach, which includes the joint, to stop water intrusion. The expectation that a single-stage joint can be installed and perform “perfectly” over the lifetime of the system, so as to prevent the entry of air/water, is unrealistic. Sealants fail.
Requiring other components of the building envelope (windows and doors), to perform to a “waterproof standard” when installed in an EIFS-clad structure when code requires only a “water resistant standard”, places an unfair burden of liability on the manufacturers of these product.
Advertising by the EIFS industry of these products as “virtually maintenance-free” but placing the blame on homeowners for “adequately failing to maintain” these systems when water intrusion occurs, is downright offensive. Particularly when water intrusion of these systems was known to the industry, including Sto, many years ago.
One of the pioneers in building envelope research, G. “Kirby” Garden, wrote extensively on the subject of water penetration of buildings long before these systems were introduced by Dryvit in 1969 and by the introduction of your company’s product to the U.S. market in 1981 In “Rain Penetration and its Control”, published in 1963, Mr. Garden states:
“The face seal approach attempts to eliminate all the openings in the wall through which water can pass. However, the materials used to seal all these openings are exposed to extremes of weather and to movements of the building. Even if the problems of job site inaccuracies and poor workmanship can be overcome and a perfect seal can be achieved, the in-service weather conditions may eventually cause the deterioration and failure of these seals, creating openings in the wall through which water can pass. Unfortunately, these openings can be extremely tiny and difficult to identify, so that even an extensive maintenance program may not keep the building free of openings.“
It would appear that the significance of these findings was not missed by at least one employee of your company. In an application to the U.S. Patent Office in July 1993 for an invention (pressure equalized rainscreen), the same Mr. Edgar mentioned in the above News Release states, in part:
Background of the Invention:
The present invention relates to a system for insulating and finishing the exterior of a building.
Rain penetration is one of the oldest problems building owners have had to deal with yet it still occurs all too frequently. The penetration of rain not only can damage interior finishes and materials but it can also damage the structure of the walls themselves.
Rain penetration results when a combination exists of water at the surface of the wall, openings through which it can pass, and a force to move the water through these openings. The elimination of any one of these three conditions could prevent the occurrence of rain penetration. While wide roof overhangs may help to shelter the walls of a low-rise building, similar protection is not available to higher buildings. Therefore, one of the remaining two conditions must be eliminated to prevent rain penetration.
The face seal approach attempts to eliminate all the openings in the wall through which water can pass. However, the materials used to seal all these openings are exposed to extremes of weather and to movements of the building. Even if the problems of job site inaccuracies and poor workmanship can be overcome and a perfect seal can be achieved, the in-service weather conditions may eventually cause the deterioration and failure of these seals, creating openings in the wall through which water can pass. Unfortunately, these openings can be extremely tiny and difficult to identify, so that even an extensive maintenance program may not keep the building free of openings
The alternate approach to controlling rain penetration is to eliminate the forces which drive or draw water into the wall. There are typically considered to be four such forces: kinetic energy, capillarity, gravity and wind pressure differences.”
An air pressure difference across the wall of a building is created by stack effect, wind and/or mechanical ventilation. If the pressure on the exterior face of the wall is higher than on the interior of the wall, water can be forced through tiny openings in the wall. Research has shown that the amount of rain moved through the cladding by this mechanism is the most significant. It has previously been recognized that this force can be eliminated or reduced by the use of the pressure-equalized cavity.
The theory of the pressure equalized cladding is that it neutralizes the air pressure difference across the cladding (caused by wind) which causes water penetration. It is impossible to prevent wind from blowing on a building but it is possible to counteract the pressure of the wind so that the pressure difference across the exterior cladding of the wall is close to zero. If the pressure difference across the cladding is zero, one of the main forces of rain penetration is eliminated.
Brief Summary of the Invention:
:It is an object of the present invention to provide an exterior insulation rainscreen structure that obviates or mitigates the above disadvantages.
In stating to the U.S. Federal government that, the “object of the present invention” was to “mitigate the disadvantages” of other EIFSystems, but failing to acknowledge same by removing its own product from the U.S. market, even after the Patent was assigned to Sto, leaves me to ask the following.
If there wasn’t a need to “mitigate the disadvantages” of other systems, why was the new system necessary?
If there weren’t “disadvantages” with the other systems, was Patent, No. 5,410,852 granted in May 1995 and assigned to Sto Aktiengesellschaft, obtained by fraudulent means?
Also, while mention is made in Sto literature that EIFS should be applied to vertical or sloped surfaces to facilitate run-off, I have not been able to locate, any warning to consumers that prolonged accumulation of snow (or water) beside the system, may result in emulsification of the finish coat and possible water entry. On the contrary, your company’s web site states, “Sto Finish Systems are designed for buildings of all construction types, in all climates”. Although no longer permitted (by specification/local building codes), certainly this is a potential problem where EIFS has already been installed to grade in areas of the country experiencing long, snowy winters. Homeowners have the right to know, Sto has the duty to inform them.
The photographs shown below were copied from your website recently.
A casual observer looking at these photographs may well assume from the photograph on the left, that if sealant is not visible around the window, it is due to an error in installation on the part of the applicator or builder. There is no acknowledgment that at one time, a different form of sealant material was permitted. This product, “Sto Seal,” when carefully applied following the directions published and distributed by Sto, results in the same/similar appearance as an installation without a backer rod or sealant as the expansion tape was covered with finish coat
The items referred to above are an example, I believe, of what appears to be a deliberate, on-going attempt by Sto Corp., EIMA and various other EIFS-industry entities to prevent the public from learning of the inherent flaw in a barrier EIFSystem.
Whatever the reasons are for these omissions from your website, one thing remains very clear. Intrusion of rainwater behind the barrier EIFSystem is reasonably foreseeable and must be managed in some way.
Defense of a defective product is unacceptable at any time but when it is from a corporation whose motto is “Building with Conscience” it is simply unforgivable as well.
Helen M. Parker-Smith
Oakton, VA
