A historic brick building in Germany covered with EIFS on the right side.
Exterior insulation and finish system (EIFS) is a general class of non-load bearing building cladding systems that provides exterior walls with an insulated, water-resistant, finished surface in an integrated composite material system.
EIFS has been in use since the 1960s in North America and was first used on masonry buildings. Since the 1990s, the majority of wood-framed buildings have used EIFS.
History of EIFS
EIFS was developed in Europe after World War II and was initially used to retrofitmasonry walls.[1] EIFS started to be used in North America in the 1960s, at first on commercial masonry buildings. EIFS became popular in the mid-1970s due to the oil embargo and the resultant surge in interest in insulating wall systems that conserve energy used for heating and cooling.[1]
In the late 1980s problems started developing due to water leakage in EIFS-clad buildings. This led to international controversy and lawsuits. EIFS installation was found to be a contributing factor in the multibillion-dollar problem known as the "Leaky condo crisis" in southwestern British Columbia and the "Leaky homes" issue in New Zealand that emerged separately in the 1980s and 1990s.[2][3][4]
Critics argue that, while not inherently more prone to water penetration than other exterior finishes, barrier-type EIFS systems (non-water-managed systems) do not allow water that does penetrate the building to escape.[5] The EIFS industry has consistently maintained that poor craftsmanship and bad architectural detailing at the perimeter of the EIFS was the problem. As a result, building codes began mandating a drainage system for EIFS systems on wood-frame buildings and additional on-site inspection.
Though there are some cases where insurance companies may not offer coverage for EIFS, several companies do.[6] EIFS systems installed at lower building levels are subject to vandalism, as the material is soft and can be chipped or carved resulting in significant damage. In these cases, heavier ounce reinforcing mesh can drastically increase the durability of the EIFS system.[7]
EIFS is now used all over North America, and in other areas around the world, especially in Europe and the Pacific Rim.[8] The use of EIFS over stud-and-sheathing framing instead of over solid walls is a technique used primarily in North America. As of 1997 EIFS accounted for about 4% of the residential siding market and 12% of the commercial siding market.[1]
Terminology
In the United States, the International Building Code and ASTM International define Exterior Insulation and Finish System (EIFS) as a non-load-bearing exterior wall cladding system that consists of an insulation board attached either adhesively, mechanically, or both, to the substrate; an integrally reinforced base coat; and a textured protective finish coat.[9]
The predominant method of EIFS applied today is EIFS with Drainage, which provides a way for moisture accumulated in the wall cavity to evacuate.[9]
EIFS is not stucco despite often called "synthetic stucco". Traditional stucco is a centuries-old, hard, dense, thick, non-insulating material which consists of aggregate, a binder, and water. 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. A common example is one-coat stucco, which is a thick, synthetic stucco applied in a single layer (traditional stucco is applied in 3 layers).
EIFS are proprietary systems of a particular EIFS manufacturer and consist of specific components. EIFS are not generic products made from common separate materials. The materials and installation methods specified by different EIFS manufacturers are not all compatible and should not be used interchangeably in new construction or repair work.[10]
The technical definition of an EIFS does not include wall framing, sheathing, flashings, caulking, water barriers, windows, doors, and other wall components. However, some architects have begun specifying flashings, sealants, and wiring fasteners as being a part of the EIFS scope of work. Many of the EIFS manufacturers have their own standard details showing typical building conditions for window and door flashings, control joints, inside/outside corners, penetrations, and joints at dissimilar materials which should be followed for that manufacturer's warranty.
EIFS installation
EIFS are typically attached to the outside face of exterior walls with an adhesive (cementitious or acrylic based) or mechanical fasteners. Adhesives are commonly used to attach EIFS to gypsum board, cement board, or concrete substrates. EIFS are attached with mechanical fasteners (specially designed for this application) when installed over house wraps (sheet-good weather barriers) such as are commonly used over wood sheathings.
EIFS since year 2000
Research, conducted by the Oak Ridge National Laboratory and supported by the Department of Energy, has affirmed that EIFS are the "best performing cladding"[11] in relation to thermal and moisture control when compared to brick, stucco, and cementitious fiberboard siding. EIFS are in compliance with modern building codes that emphasize energy conservation through the use of CI (continuous insulation) and a continuous air barrier.[12]
EIFS before 2000 were barrier systems, meaning that the EIFS itself was the weather barrier. After 2000, the EIFS industry introduced the air/moisture barrier that resides behind the foam. In a study done by the Department Of Energy's Office of Science - Oak Ridge National Laboratory, it was found that the best air/moisture barrier was a fluid barrier. The Oak Ridge National Laboratory, ATLANTA, Oct. 28, 2006 — EIFS "outperformed all other walls in terms of moisture while maintaining superior thermal performance." The National Institute of Standards and Technology (NIST) has evaluated the five life cycle stages of the environmental impact of EIFS alongside brick, aluminum, stucco, vinyl, and cedar. Depending on a variety of site and project specific conditions, EIFS have the potential to save money in construction costs and contribute toward energy efficient operations and environmental responsibility when correctly designed and executed.[13]
Some types of EIFS have passed some fire tests that range from resistance to ignitability, that include: ASTM E 119, NFPA 268, NFPA 285.[14] However, some types and thicknesses of EIFS have been involved in large uncontrolled exterior building fires, such as the 2008 Monte Carlo Hotel Casino fire.[15]
Composition & types of EIFS
Types of External Wall Insulation Systems (EWIS)
Types of EIFS are defined by their materials and the existence/absence of a drainage plane. The EIFS Industry Members Association (EIMA) defines two classes of EIFS: Class PB (polymer based) identified as PB EIFS, and Class PM (polymer modified) identified as PM EIFS.
PB EIFS is the most common type in North America. It uses expanded polystyrene (EPS) insulation adhered to the substrate with fiberglass mesh embedded in a nominal 1⁄16 inch (1.6mm) base coat which can receive additional layers of mesh for stronger impact resistance. Other types of insulation board can include polyisocyanurate.
PM EIFS use extruded polystyrene insulation (XEPS) and a thick, cementitious base coat applied over mechanically attached glass fiber reinforcing mesh. The system has joints similar to traditional stucco. PM EIFS have evolved to include different insulation materials and base coats.
The most common type of EIFS used today is the system that includes a drainage cavity, which allows any and all moisture to exit the wall. EIFS with drainage typically consists of the following components:
An optional water-resistive barrier (WRB) that covers the substrate.
A drainage plane between the WRB and the insulation board that is most commonly achieved with vertical ribbons of adhesive applied over the WRB.
Insulation board typically made of expanded polystyrene (EPS) which is secured with an adhesive or mechanically to the substrate.
A water-resistant base coat that is applied on top of the insulation to serve as a weather barrier.
A finish coat that typically uses colorfast and crack-resistant acrylic co-polymer technology.[12]
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 glass faced exterior-grade gypsum sheathing, oriented strand board (OSB) or plywood).[16] 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 and 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 used 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. Adhesives come in two forms: The most common is in a plastic pail as a paste, to which Portland cement is added and 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.
Legal issues
EIFS systems have been the subject of several lawsuits in the United States, 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.[17]
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 must be carefully applied by skilled craftsmen. General contractors switched to EIFS because they were 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 installers cut corners by using insufficiently trained labor and also failed to supervise their work adequately. 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 installing contractors, the construction industry has retorted that using 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 & the EIFS industry
EIFS account for about 10% of the US commercial wall cladding market.[18] There are several dozen EIFS manufacturers in North America. Some sell nationwide, and some are regional in their area of business operations. The top five EIFS producers account for about 90% of the US market. These producers include Dryvit Systems, STO Corp., BASF Wall Systems, Master Wall, and Parex.[19][20]
EIFS architectural details
EIFS offer the option of adding architectural details that are composed of the same materials. These mouldings come in a variety of shapes and sizes. They are widely used on residential and commercial projects in North America and are gaining popularity worldwide.
Related Research Articles
A wall is a structure and a surface that defines an area; carries a load; provides security, shelter, or soundproofing; or, is decorative. There are many kinds of walls, including:
An earth shelter, also called an earth house, earth-bermed house, earth-sheltered house, earth-covered house, or underground house, is a structure with earth (soil) against the walls and/or on the roof, or that is entirely buried underground.
Plaster is a building material used for the protective or decorative coating of walls and ceilings and for moulding and casting decorative elements. In English, "plaster" usually means a material used for the interiors of buildings, while "render" commonly refers to external applications. The term stucco refers to plasterwork that is worked in some way to produce relief decoration, rather than flat surfaces.
Stucco or render is a construction material made of aggregates, a binder, and water. Stucco is applied wet and hardens to a very dense solid. It is used as a decorative coating for walls and ceilings, exterior walls, and as a sculptural and artistic material in architecture. Stucco can be applied on construction materials such as metal, expanded metal lath, concrete, cinder block, or clay brick and adobe for decorative and structural purposes.
Siding or wall cladding is the protective material attached to the exterior side of a wall of a house or other building. Along with the roof, it forms the first line of defense against the elements, most importantly sun, rain/snow, heat and cold, thus creating a stable, more comfortable environment on the interior side. The siding material and style also can enhance or detract from the building's beauty. There is a wide and expanding variety of materials to side with, both natural and artificial, each with its own benefits and drawbacks. Masonry walls as such do not require siding, but any wall can be sided. Walls that are internally framed, whether with wood, or steel I-beams, however, must always be sided.
This page is a list of construction topics.
A vapor barrier is any material used for damp proofing, typically a plastic or foil sheet, that resists diffusion of moisture through the wall, floor, ceiling, or roof assemblies of buildings and of packaging to prevent interstitial condensation. Technically, many of these materials are only vapor retarders as they have varying degrees of permeability.
A building envelope or building enclosure is the physical separator between the conditioned and unconditioned environment of a building, including the resistance to air, water, heat, light, and noise transfer.
Housewrap, also known by the genericized trademark homewrap, generally denotes a modern synthetic material used to protect buildings. Housewrap functions as a weather-resistant barrier, preventing rain or other forms of moisture from getting into the wall assembly while allowing water vapor to pass to the exterior. If moisture from either direction is allowed to build up within stud or cavity walls, mold and rot can set in and fiberglass or cellulose insulation will lose its R-value because of the heat-conducting moisture. House wrap may also serve as an air barrier if it is sealed carefully at seams.
A cavity wall is a type of wall that has an airspace between the outer face and the inner, usually structural, construction. The skins typically are masonry, such as brick or cinder block. Masonry is an absorbent material that can retain rainwater or condensation. One function of the cavity is to drain water through weep holes at the base of the wall system or above windows. The weep holes provide a drainage path through the cavity that allows accumulated water an outlet to the exterior of the structure. Usually, weep holes are created by leaving out mortar at the vertical joints between bricks at regular intervals, by the insertion of tubes, or by inserting an absorbent wicking material into the joint. Weep holes are placed wherever a cavity is interrupted by a horizontal element, such as door or window lintels, masonry bearing angles, or slabs. A cavity wall with masonry as both inner and outer vertical elements is more commonly referred to as a double wythe masonry wall.
Stone veneer is a thin layer of any stone used as decorative facing material that is not meant to be load bearing. Stone cladding is a stone veneer, or simulated stone, applied to a building or other structure made of a material other than stone. Stone cladding is sometimes applied to concrete and steel buildings as part of their original architectural design.
Screed has three meanings in building construction:
A flat board or a purpose-made aluminium tool used to smooth and to "true" materials like concrete, stucco and plaster after they have been placed on a surface or to assist in flattening;
A strip of plaster or wood applied to a surface to act as a guide for a screed tool ;
The material itself which has been flattened with a screed. In the UK, screed has also come to describe a thin, top layer of material, poured in place on top of the structural concrete or insulation, on top of which other finishing materials can be applied, or the structural material can be left bare to achieve a raw effect.
Building insulation materials are the building materials that form the thermal envelope of a building or otherwise reduce heat transfer.
Cellulose insulation is plant fiber used in wall and roof cavities to insulate, draught proof and reduce noise. Building insulation in general is low-thermal-conductivity material used to reduce building heat loss and gain and reduce noise transmission.
Rigid panel insulation, also referred to as continuous insulation, can be made from foam plastics such as polyurethane (PUR), polyisocyanurate (PIR), and polystyrene, or from fibrous materials such as fiberglass, rock and slag wool. Rigid panel continuous insulation is often used to provide a thermal break in the building envelope, thus reducing thermal bridging.
An external wall insulation system is a thermally insulated, protective, and decorative exterior cladding procedure involving the use of expanded polystyrene, mineral wool, polyurethane foam or phenolic foam, topped off with a reinforced cement based, mineral or synthetic finish and plaster.
Cement render or cement plaster is the application of a mortar mix of sand and cement, and water to brick, concrete, stone, or mud brick. It is often textured, colored, or painted after application. It is generally used on exterior walls but can be used to feature an interior wall. Depending on the 'look' required, rendering can be fine or coarse, textured or smooth, natural or colored, pigmented or painted.
Magnesium oxide, more commonly called magnesia, is a mineral that when used as part of a cement mixture and cast into thin cement panels under proper curing procedures and practices can be used in residential and commercial building construction. Some versions are suitable for general building uses and for applications that require fire resistance, mold and mildew control, as well as sound-control applications. Magnesia board has strength and resistance due to very strong bonds between magnesium and oxygen atoms that form magnesium oxide crystals.
A rainscreen is an exterior wall detail where the siding stands off from the moisture-resistant surface of an air/water barrier applied to the sheathing to create a capillary break and to allow drainage and evaporation. The rainscreen is the cladding or siding itself but the term rainscreen implies a system of building. Ideally the rainscreen prevents the wall air/water barrier from getting wet but because of cladding attachments and penetrations water is likely to reach this point, and hence materials are selected to be moisture tolerant and integrated with flashing. In some cases a rainscreen wall is called a pressure-equalized rainscreen wall where the ventilation openings are large enough for the air pressure to nearly equalize on both sides of the rain screen, but this name has been criticized as being redundant and is only useful to scientists and engineers.
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