EIFS

EIFS

GWINNETT PROPERTY INSPECTIONS

EIFS - Exterior Insulation and Finishing Systems

Because EIFS (Exterior Insulated Finish Systems) rely on a perfect seal at the exterior surfaces, they are susceptible to entrapment of moisture inside the system. Water can enter the system where seams and seals fail, where moisture migrates from inside the building and where punched openings (windows, doors, etc.) are present. Because of the low vapor permeability of the finish, water trapped behind the EIFS cannot dry out quickly toward the outside of the wall (see figure 1). Depending on the rest of the wall system design and installation, there may also be limited drying potential to the inside. Limited drying potential in combination with high leakage potential can lead to moisture buildup inside the wall, and eventually to mold growth and structural decay.

What Is EIFS (Exterior Insulated Finish Systems)?

While giving the appearance of stucco, EIFS is actually a multi-layered wall system that consists of the following components:

	Insulation Board - Made of polystyrene (or similar material), which is secured to the exterior wall surface.
	Base Coat - Applied on top of the insulation and reinforced with fiber mesh.
	Finish Coat - Applied on top of the base coat giving a durable, crack-resistant finish.

The first half of the acronym, "Exterior Insulation" is derived from the fact that the first component installed is a foam insulation board. The foam board is mechanically and/or adhesively attached to the exterior sheathing of the home. In this respect the foam board serves as an exterior insulating layer. Over this foam board is applied a synthetic base-coat material in which is embedded a fiberglass reinforcing mesh. This is typically referred to as the "base-coat". On top of the base coat is applied one or more "finish coats". This is the exterior layer that gives the product its stucco-like appearance. Hence the second part of the acronym "Finish Systems".

EFIS provides many advantages that other exterior finishes and sidings do not. Chief among these are superior energy efficiency and great design flexibility. As a matter of fact, studies have shown that EIFS can reduce the air infiltration in a wall by as much as 55%, when compared to standard brick or wood construction. One should bear in mind that an EIFS system is a non-structural component of the wall. In other words, it is not designed to be weight bearing.

Most early EIFS employed a face seal approach to rainwater management, and was thus very susceptible to failure. Because of these early problems, most EIFS now incorporates some sort of a drainage plane to allow for moisture drainage. Newer installations incorporating this design could be considered concealed barrier systems. However, due to the nature of the product and the realities of the construction process, even newer drainage EIFS systems can experience problems:

	“Short-cuts” are often taken in the application of EIFS systems, causing the primary face seal moisture barrier to fail and leak (lack of proper caulking, flashing, etc.).
	The integrity of the second line of defense is highly dependent on correct detailing by the designer and proper installation by the builder and his subcontractors. Very often, flashings, housewrap, windows, doors, etc., are improperly installed.
	EIFS does not breathe and will not allow trapped moisture to evaporate easily, which can cause great damage over time.

The Causes Of Most EIFS Problems

Since EIFS clearly provides many advantages, what's the big deal? The basic problem begins with the erroneous belief that homes can be made to be “water proof”. The simple truth is, they cannot. For example, even when applied by professional caulking applicators, All caulk joints will eventually fail. . . .even those caulk joints made under laboratory conditions. No residential windows are fully waterproof. . . .they are designed and manufactured to a water-resistant standard. Some water will always find a way in. When it can't get out, you have a problem.

A. Why Can EIFS Be A Problem?

Homes clad with EIFS (Exterior Insulation and Finish Systems) a.k.a. synthetic stucco have a very strong tendency to retain moisture between the sheathing of the home and the finish system. The design of EIFS, unlike other systems (brick, stone, siding, etc.), does not allow the moisture to drain out. The problem is water intrusion and entrapment in the wall cavities. The moisture can sit in contact with the sheathing for a prolonged period and rotting may result. Damage can be serious.

While a brick or stone wall will contain an internal drainage plane behind it and weep holes along the bottom edge to allow for water drainage, moisture intruding into the EIFS wall cavities is more damaging because it cannot readily escape back out through the waterproof EIFS exterior as quickly as it can through brick veneer, stone, or cement stucco, leaving the internal sheathing and wood framing vulnerable to rot and decay.

Successful installation of EIFS depends upon keeping water out of the wall cavities. Consequently, in an effort to keep the water out, an industry-wide installation standard was developed that details installation procedures to be followed. In conjunction with this, the EIFS manufacturers then trained and certified applicators to install their products and supplied them with materials which met specification standards.

But, here is where the system begins to break down, because unfortunately, the manufacturers failed to take into account the realities of residential construction:

	Barrier type systems rarely work. The EIFS external barrier system depends upon a perfect external water barrier to keep water out of wall cavities. Since the outer shell is the only barrier against water intrusion, it must form a “perfect” barrier at “all times.” When there are so many entry points for water intrusion in the exterior shell of a house, this is an unrealistic expectation.
	Lack of inspection and enforcement of standards. Most manufacturers, unrealistically expected that the building industry on its own (including public inspection departments), would maintain industry standards & specifications, provide oversight, and provide inspection of the EIF system as it was installed. Everyone thought that someone else was minding the store, consequently, the vast majority of EIFS applications nation-wide, have never been inspected. Compounding this problem is the fact that the EIFS manufacturers have failed to insist upon the very standards they helped originate, be met by the applicators they supply materials to.
	Evolution of application guidelines. Another consideration is that guidelines for EIFS installation have been evolving over the years. An example of this is below grade termination of the EIFS. While not allowed by building code, early on, it was allowed by some manufacturers specifications. However, due to problems with this type of application nation-wide, in 1996 Dryvit Corp (one of the largest EIFS manufacturers), changed all of its specifications to require an 8 inch separation be left between the EIFS and soil (termite problems in the South & carpenter ants in the North, moisture wicking up into the EIFS, frost damage, inability of the EIFS to drain water away if it is buried, etc.). Unfortunately, this type of new information has been slow to “trickle down” through the information chain (from the manufacturer è distributor è applicator). Some distributors even claim their insulation-board doesn’t wick water, and consequently can be placed below grade (experience shows that it does, however).
	Leaks and damage are hidden from view. There are few, if any, external visual clues to an early leakage problem. As a matter of fact, it can take years for an intermittent leak to evidence itself as damaged sheathing, window leaks, rotted framing, mold growth, etc. Many insurance companies, builders, and applicators may not take a leakage problem seriously, until they can actually see the damage. The reason for this “mind-set” is understandable, because no one wants to be responsible to pay for repairs that may be unnecessary. Unfortunately, by waiting until a problem is noticeable as visible damage, the word repair can become the word replace. What was once a relatively inexpensive repair has become a very expensive replacement.