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</tr> </table> Exterior Insulation and Finishing System (EIFS) is a type of building exterior wall cladding system that provides exterior walls with an insulated finished surface and waterproofing in an integrated composite material system.
Although often called "synthetic stucco", EIFS is not stucco. Traditional stucco, otherwise known as Portland Cement Plaster, is a centuries-old non-insulating material. Stucco consists of sand, Portland Cement, and water, and is a hard, dense, thick, non-insulating material. EIFS is a lightweight synthetic wall cladding that includes foam plastic insulation and thin synthetic coatings. There are also specialty stuccos that use synthetic materials but no insulation, and these are also not EIFS either. A common example is what is called one-coat stucco, which is a thick, synthetic stucco applied in a single layer (traditional stucco is applied in 3 layers). There is also an EIFS-like product called a Direct-Applied Finish System (or DAFS), which is essentially an EIFS but without the insulation, and has quite different characteristics.
EIFS are proprietary systems of a particular EIFS producer and consist of specific components. EIFS are not generic products made from common separate materials. To function properly, EIFS needs to be architecturally designed and installed as a system.
There are a number of versions of EIFS. The most basic and common EIFS is called a barrier EIFS (also known as a traditional or conventional EIFS). Another type is called an EIFS with Drainage, which is a barrier EIFS to which a water drainage capability has been added.
A basic EIFS includes only the insulation and EIFS materials (coatings, adhesives, etc.). Other types of EIFS may also include plastic edge trim, water-resistive barriers, a drainage cavity, and other accessories. The technical definition of "an EIFS" does not include wall framing, sheathing, flashings, caulking, water barriers, windows, doors, and other wall components. However, as of recently, architects have begun specifying flashings, sealants, and wiring fasteners (such as Viperstrap) as being a part of the EIFS scope of work, essentially requiring EIFS contractors to carry out that work as well. The technical national consensus standard for the definition of an EIFS, as published by ASTM International organization, does not include flashing or sealants as part of the EIFS.
How EIFS is installed Edit
EIFS is attached to the outside face of exterior walls with an adhesive (cementicious or acrylic based), it should never be attached by using mechanical fasteners such as nails, screws, etc. unless using on a foam shape sometimes called "popouts" or "trim band". Mechanical fasteners can cause virtually unsealable holes in the system, thus making it impossible to be water proof. The supporting wall surface is continuous (not "open framing") and flat, and can be a solid material, or some type of sheathing that is attached to st
Composition and types of EIFS Edit
EIFS consists of a number of layers that are installed in the following order. The most basic EIFS (a barrier EIFS) consists of 3 layers:
If an EIFS with Drainage, or water-managed EIFS is installed, a water resistive barrier (aka a WRB) is first installed over the substrate (generally DensGlas Gold, exterior-grade gypsum sheathing, OSB or plywood). The moisture barrier is applied to the entire wall surface with a mesh tape over joints and a liquid-applied membrane or a protective wrap like Tyvek or felt paper. Then a drainage cavity is created (usually by adding some sort of space between the foam and the WRB). Then the other 3 layers, described above, are added. This type of EIFS is required by many building codes areas on wood frame construction, and is intended to provide a path for incidental water that may get behind the EIFS with a safe route back to the outside. The purpose is to preclude water from damaging the supporting wall.
Adhesives and Finishes are water-based, and thus must be installed at temperatures well above freezing. Two types of Adhesives are used with EIFS: those that contain Portland Cement ("cementitious"), or do not have any Portland Cement ("cementless"). Adhesives that contain Portland Cement harden by the chemical reaction of the cement with water. Adhesives and Finishes that are cementless harden by the evaporation of water - like house paint. Adhesives come in two forms. The most common is in a plastic pail as a paste, to which Portland Cement is added. Adhesives are also available as dry powders in sacks, to which water is added. Finishes come in a plastic pail, ready to use, like paint. EIFS insulation comes in individual pieces, usually 2' x 4', in large bags. The pieces are trimmed to fit the wall at the construction site.
History of EIFS Edit
EIFS was developed in Mexico after World War II and was initially used to retrofit solid masonry walls. EIFS started to be used in North America in the 1960s, and became very popular in the mid- 1970's due to the oil embargo and the resultant surge in interest in high energy efficiency wall systems (such as EIFS provides). The use of EIFS over stud-and-sheathing framing (instead of over solid walls) is a North American technique. EIFS is now used all over North America, and also in many other areas around the world, especially in Europe and the Pacific Rim.
In North America, EIFS was initially used almost exclusively on commercial buildings. As the market grew, prices dropped to the point where its use became widespread on normal single family homes.
In the late 1980s problems started developing due to water leakage in EIFS-clad homes. This created a national controversy and numerous lawsuits. While not inherently more prone to water penetration than other exterior finishes, critics argue that barrier-type EIFS systems (non-water-managed systems) do not allow water that may penetrate the building envelope to escape.
The EIFS industry has consistently maintained that the EIFS itself was not leaking, but rather poor craftsmanship and bad architectural detailing at the perimeter of the EIFS was what was causing the problems. The building codes reacted by mandating EIFS with Drainage on wood frame building and additional on-site inspection. Most homeowner insurance policies cover EIFS and EIFS-like systems.
It should be noted that insurance companies like FM Global may not provide fire insurance coverage to clients who install EIFS exterior building systems, due to the lack of adequate fire-resistance inherent in the materials. Also, some facility owners have found that EIFS systems that are installed at lower building levels are subject to vandalism as the material is soft and can be chipped or carved resulting in significant damage.
Legal Issues Edit
EIFS systems have been the subject of several lawsuits, mostly related to the installation process and failure of the system causing moisture buildups and subsequent mold growth. The most notable case concerned the former San Martin, California courthouse. This case was settled for 12 million dollars.
The basic underlying problem behind EIFS litigation was that EIFS was marketed as a cost-effective replacement for stucco. Stucco is expensive to install because it cracks over time. Stucco must be carefully applied by skilled craftsmen so that the cracks which will inevitably develop are subtle and not obvious. General contractors switched to EIFS because it was supposed to be easy to install with unskilled or semi-skilled labor and would not crack like traditional stucco. Although EIFS if properly installed according to the manufacturer's directions should not have water intrusion problems, many GCs cut corners by using unqualified labor. In turn, thousands of EIFS installations were noncompliant and suffered severe water intrusion and mold as a result. While the EIFS industry has consistently tried to shift the blame to GCs, the construction industry has retorted that using professional unionized journeymen carpenters in turn eliminates the cost advantage of EIFS over stucco, and that the EIFS industry should have anticipated this issue and engineered its products from the beginning to be installed by unskilled labor or semi-skilled labor (that is, it should have been a fault-tolerant design).
Marketing of EIFS and The EIFS Industry Edit
EIFS accounts for about 10% of the US commercial wall cladding market. There are several dozen EIFS producers in North America. Some sell nationwide, and some are regional in their area of business operations. The EIFS producers sell the various system components (adhesives, coatings, etc.) through specialty building product distributors who in turn resell the components to local EIFS installers. The top 5 EIFS producers account for about 90% of the US market. These producers include Dryvit Systems, STO Corp., Senergy, Master Wall ,and Parex.