What Is EIFS?

Exterior Insulation and Finish Systems (EIFS) are multi-layered exterior wall systems that are used on both commercial buildings and homes. They provide superior energy efficiency and offer much greater design flexibility than other cladding products.

Developed in Europe in the 1950s, EIFS were introduced in the U.S. almost 30 years ago. They were first used on commercial buildings, and later, on homes. Today, EIFS account for nearly 30% of the U.S. commercial exterior wall market. EIFS typically consist of the following components:

Resource:

-© 2002 EIFS Industry
Members Association
1-800-294-3462

Evaluating EIFS

In many cases, we are asked to evaluate EIFS on buildings by the potential buyer of the property. This situation creates some unique problems which must be addressed by the consultant. In most cases, the owner of the building does not want or allow any type of destructive testing of the building they own. The consulting company must try to assess the building using non-destructive methods. This can be done using electronic moisture detection equipment such as a Tramex "Wet Wall". This alone will not provide the level of security you are probably seeking.

Closer Look Inspections utilizes Infrared Thermography to assess the Exterior Insulation Finish System for suspect areas of moisture damage and/or penetration. This is the most cost effective and accurate method of spotting potential problems using non-destructive methods. If anomalies are spotted during our scan of the exterior building envelope, we try to verify the high moisture content using the Tramex "Wet Wall" meter. If this meter also indicates a problem exists, it would be wise to insist that more invasive assessments be performed. This will include using electronic moisture meters (e.g. Delmhorst) that have long pins for penetrating the insulation to the exterior wood sheathing to determine moisture levels behind the EIFS. If the pin meter indicates excessive moisture exists art the sheathing level a decision will have to be made on how to proceed. This is when the experience of your consultant will be important.

First, it is important that the consulting company you hire has not only an understanding of EIFS. The firm should have a professional level understanding of building science including evaluating pressures across the building envelope, evaluating indoor air quality concerns, thermography, blower door testing and other areas which may be required to make a thorough assessment of what conditions must be addressed to remediate the problems. It is at the stage of the assessment that an improper diagnosis may create new problems or worsen existing problems. This is where many inspectors do not understand building science and/or EIFS. A properly installed EIFS application may still be playing a role in moisture issues in the building. This is due to a lack of drainage when water vapor enters the interstitial wall cavity. If the building has EIFS on the exterior and a semi-vapor impermeable or impermeable (e.g. vinyl wallpaper) wall finish at the interior problems can occur within the interstitial wall space when moist indoor air meets dew point temperature s inside the interstitial wall space.

Second, whenever there are water problems involving cellulose based building materials coupled with no drainage from the wall cavity, fungal amplification is a likely prospect. This should be evaluated by a consulting firm understands the entire science of the building including psychrometric analysis, building pressures, HVAC system operation and balancing and indoor air quality. Closer Look Inspections associates include state licensed HVAC mechanics, certified balancing professionals, thermographers, code certified inspectors and engineers. A thorough evaluation will assure that all areas of the building are assessed so that band-aid type repairs do not come back to haunt you later.

Most wood-framed residential homes require a secondary weather barrier to be placed over the sheathing before the exterior cladding is installed. This barrier protects the home from incidental water intrusion and allows moisture to exit the home by traveling on top of the barrier, keeping the sheathing and structural members relatively dry. Eliminating a barrier and rendering a substrate unprotected invites trouble, no matter what type of exterior cladding is used.

Due to the design of the EIFS, a majority of EIFS clad homes do not have a secondary weather barrier placed over the exterior sheathing. A large number of EIFS applications use an adhesive to fasten the two-foot by four-foot insulation boards to the sheathing. If an adhesive is used to hold the insulation boards to the sheathing, then a secondary weather barrier cannot be used. Any water that infiltrates the system will become trapped between the EIFS and the sheathing.

Newer drainage EIFS has addressed this problem by adding a drainage plane behind the EPS to allow any moisture to drain before causing damage. The lack of this drainage plane in the majority of older EIFS installations can be problematic if the installers did not pay attention to details (e.g. window flashing, roof/wall flashing, deck flashing, etc.). This can also pose a problem from the interior based on vapor diffusion entering the wall cavity from the interior. Depending on the interior finishes, vapor pressures, pressures across the building envelope and other factors, moisture can become trapped in the interstitial wall space with no way out. This greatly increases the humidity levels within the interstitial space which can lead to conditions favorable to microbial amplification and may begin to damage structural components.

It is estimated that 95 percent of homes clad with EIFS in the United States are barrier-type. Most barrier EIFS projects are adhesively applied because it is less time consuming to install. Adhesively applied EIFS prohibits a vapor barrier from being installed. It also prevents many self-flashing windows from being installed properly since the sill flashing must be cut off to accommodate the adhesively attached foam board.

Drainage EIFS

EIFS Segment (from Dryvit Site)

EIFS Photo Gallery

EIFS installations are especially vulnerable around doors and windows	Infrared Thermography used to evaluate EIFS installation	Thermography made spotting this suspect leakage area easier to locate	All joints, control joints and areas where disimilar materials abutt should be carefully evaluated
This home had many vulnerable areas	Areas around window were found to be leaking. This also poses mold and other indoor air quality concerns	Termination above basement windows	Taking an air sample from wall cavity using WallChek system.
Roof/Wall termination at penthouse on commercial EIFS project	Typical EIFS leakage area at bottom corner of window discovered using infrared technology	Improper deck termination at EIFS wall.	Moisture meters used to measure moisture content of EIFS, concrete, wood, roof membranes, etc.

Resources: