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EIFS Frequently Asked Questions (FAQ)

Q: What is EIFS?

A: EIFS is a relatively new product which uses plasticizers to modify traditional cement stucco and make it more flexible. This allows application in a thinner coating which saves time and material. The system also includes an insulation layer that improves system and building performance.  The entire modern EIFS system consists of a moisture barrier (usually), the foam insulation, the plastic-cement basecoat, fiberglass reinforcing mesh, and finishes.  EIFS stands for Exterior Insulated Finish System.

Q: What's the difference between EIFS and Stucco?

Traditional cement stucco is applied in three relatively thick coats, to a total thickness of nearly one inch.  The "stucco" part of the EIFS is generally less than 1/4" in thickness.  But the picture is not nearly as black and white as many people think.  There are "polymer-modified" EIF systems that are often 1/4"-3/8" thick, yet they are still considered EIFS.  Then, there are "One-Coat" stucco products that can be applied in a single coating as think as 3/8", and these are generally considered to be "stucco", and not "EIFS."  Some contractors apply 2 coats of one coat stucco to a total thickness of nearly 3/4".  "Stucco" can be installed over foam insulation, like EIFS.  Much of the new cement stucco being applied still uses foam trim build-out details that look just like EIFS, and most modern cement stucco uses acrylic finishes, just like EIFS.  The truth is that EIFS and stucco constitute a spectrum of similar products with similar installation requirements, performance issues, and failure modes.  In most of the discussion below, you can substitute "stucco" for "EIFS" to understand that the testing of any system is important.

Q: What is the problem with EIFS?

A: Prior to the late 1990's, most residential EIFS did not incorporate a moisture barrier behind the system.  Systems without backup moisture protection are referred to as "barrier EIFS."  In order to protect the building from moisture intrusion, barrier EIFS must be perfectly sealed at the outside surface. Any moisture that penetrates the outer coating can migrate into the walls and cause substantial damage. Unfortunately, nothing is perfect, and the material tends to leak. Sometimes it leaks quite a bit. The weak point of most applications is the penetrations like windows, doors, electric and other utilities, etc. Each of these is a potential leak.  Even though most manufacturers withdrew their barrier EIFS from the residential market in the late 1990's, we still see these systems being installed now.

Q: How do I know if my EIFS is leaking?

A: First, it is important to understand that ALL EIFS is leaking. All cladding systems leak, whether made from EIFS, stucco, wood, vinyl, brick, or something more exotic.  The important question is: How Much? As long as a wall is built to dry faster than any leaks can wet it, there can be few problems. Problems occur when the water comes in faster than it goes out. Materials that stay too wet for too long tend to rot, to grow mold, and eventually to fall apart. Here in NJ, we find that many walls show signs of leakage and elevated moisture, but that the damage caused by these leaks is less severe than in other parts of the country. Still, over 90% of the EIFS houses we have inspected have at least some structural damage caused by water leakage and entrapment within the walls.

Q: So how can I tell if water is building up in my walls?

A: Only with a comprehensive visual and moisture intrusion inspection. There are many different methods and tools that can be used to identify potential trouble spots.   But regardless of how suspect areas are identified, you cannot know exactly how much moisture is trapped without penetrating the cladding and directly measuring the moisture content of the building materials inside. There is just no other way. This has been established by a number of nationally accepted test protocols, including the one we follow. You can see our test protocol by visiting the GAHI website. Their protocol states in part, "The advent of the Tramex Wet Wall Detector has eased the process of inspection. This tester will indicate areas with high or elevated moisture content. This tester will not provide specific moisture content information. An intrusive probe is required for the determination of specific moisture content. "

Some other inspectors are touting their "non-invasive" inspections. Be very careful before deciding on this type of inspection. Almost Home also uses the non-invasive scanner ( A Tramex Wet Wall Detector, or WWD) to identify wet areas within the walls, but only as a part of the complete moisture evaluation service. The manufacturer of the most popular scanner (Tramex) indicates in their user's manual that, "When the WWD has been zeroed correctly on a dry area and set on the correct range for the EIFS thickness, a higher than zero reading normally indicates higher moisture content." Read this statement very carefully.

In order for the meter to behave "normally", the test technician must know the thickness of the EIFS and the moisture content of the wall behind it. There is no way to know these critical pieces of information without penetrating the EIFS for the calibration step. If the meter was accidentally zeroed over a wet area, then the technician would miss ALL other wet areas on the house. In addition, the manufacturer says that higher readings "normally" indicate higher moisture levels. It is common for metal inside the walls to provide a false positive reading, indicating that moisture is present when in fact, there is none. We often encounter high readings with the WWD and find satisfactory moisture levels inside the wall with an invasive probe. The manufacturer also recommends in several places in their user's manual that the WWD results be checked using a penetrating probe.

Q: What about infrared (IR) inspections?

In addition to the WWD, Almost Home uses IR cameras to aid in locating moisture during our inspections.  However, we do not rely solely on the results of the IR inspection to determine whether or not there is moisture trapped in the walls.

Just like with the Tramex WWD, the IR camera can be fooled.  The cameras are very sensitive to weather conditions (the best images can often be taken only for an hour or so after sundown), and to normal wide variations in field conditions.  It is important to understand that IR cameras are sensitive only to changes in surface temperature - they cannot "see" moisture.  Occasionally, moisture inside the wall causes temperature differences on the outside, and the cameras see that temperature difference.  But they are prone to both false positives and false negatives.  They cannot differentiate between moisture stored in the basecoat and finish, moisture stored in the foam, or moisture in the walls behind the EIFS.  Only water in the walls behind the EIFS is likely to damage the house.  IR cameras can be very useful scanning tools, but again, you only know for sure how much water and damage may be behind the system by inserting probes and measuring it.

The bottom line is that the very smart Engineers at Tramex and the IR camera companies have not yet been able to find a way that their equipment can accurately measure the moisture content of the walls independent of invasive probing. What do the other inspectors know that the manufacturer's own Engineers do not? Use of these tools is an important part of a comprehensive moisture intrusion inspection, but it cannot alone give the complete and necessary information you need to properly understand the scope of any moisture problems the house may have. A house is a big investment, and EIFS problems can be expensive to repair. Do yourself a favor and hire someone who performs a complete and proper inspection.

Q: When you talk about "penetrating the EIFS": just how big a hole do you make?

A: The moisture meter uses two narrow probes that require holes the size of an ice pick (about 1/8"). Many people in the industry refer to this as a "snakebite." After testing, the holes are sealed with an appropriate caulk that is compatible with the color of the EIFS. Because of the texture of the material, the patches are generally invisible.

Q: Are there other problems beyond structural decay?

A: Yes. Some molds can cause injury or ill health to people sensitive to them.  There is a surprising amount of air exchange between wall cavities and the indoor rooms in a house. The air currents can carry mold into the living spaces of a house.  There are currently no public health standards concerning unsafe mold levels or unsafe types of mold, but a prudent homeowner will clean up any known mold sites and eliminate the moisture problems that allowed the mold growth. An industrial hygienist familiar with mold exposure and cleanup can provide further information.

Q: If my walls are wet, do I have to remove all of the cladding?

A: Not necessarily. It depends very much on how wet they are, how long they have been wet, and how much area is affected. Corrections can range from simple caulking and sealing, to partial removal and repairs, to complete removal of the system and structural repair to the walls behind. A direct moisture measurement is required to make this decision.

Q: Is there a solution for the leakage problems?

A: Yes. All of the major manufacturers are now selling products that drain. They use different approaches to provide a drainage plane behind the EIFS so that any moisture that leaks through the outer barrier can drain away to the base of the wall and seep to the outside. Traditional cement stucco has always been installed over some type of building paper to help drain this water out of the back of the system.  When properly installed, the backup water resistant barrier dramatically improves the performance over the older barrier EIFS. Of course, they will still be sensitive to proper installation, like any siding system.

Q: If I have drainable EIFS, can I still have a problem?

A: Yes. Now that drainable systems have been on the market for 10 years or so, we have had time to see them in action.  When properly applied, they work well.  Unfortunately, many builders do not follow the manufacturer's instructions, and if the backup water barrier is not done well, these systems exhibit the same failure modes as barrier EIFS.  We generally see less leakage and damage with drainable systems than with barrier systems, but we have now seen dramatic failures with both types.  Again, a comprehensive moisture evaluation is the best way to know how well your system is performing.

Q: Where can I go for more information?

A: You are welcome to contact us directly. We do our best to provide fast and free responses. If you want to hear the party line directly from the manufacturers, go to the EIFS Industry Member's Association, EIMA. If you want a homeowner's perspective, simply do a web search on EIFS - there are many tsites discussing the issues. Please remember to think critically when visiting any website.

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