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
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
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
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
and was initially used to
retrofit
Retrofitting is the addition of new technology or features to older systems. Retrofits can happen for a number of reasons, for example with big capital expenditures like naval vessels, military equipment or manufacturing plants, businesses or go ...
masonry
Masonry is the craft of building a structure with brick, stone, or similar material, including mortar plastering which are often laid in, bound, and pasted together by mortar (masonry), mortar. The term ''masonry'' can also refer to the buildin ...
walls.
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.
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
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
and the "
Leaky homes" issue in
New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
that emerged separately in the 1980s and 1990s.
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. 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
An inspection is, most generally, an organized examination or formal evaluation exercise. In engineering activities inspection involves the measurements, tests, and gauges applied to certain characteristics in regard to an object or activity. ...
.
Though there are some cases where insurance companies may not offer coverage for EIFS, several companies do. EIFS systems installed at lower building levels are subject to
vandalism
Vandalism is the action involving deliberate destruction of or damage to public or private property.
The term includes property damage, such as graffiti and defacement directed towards any property without permission of the owner. The t ...
, 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
Durability is the ability of a physical product to remain functional, without requiring excessive maintenance or repair, when faced with the challenges of normal operation over its design lifetime. There are several measures of durability in us ...
of the EIFS system.
EIFS is now used all over North America, and in other areas around the world, especially in Europe and the
Pacific Rim
The Pacific Rim comprises the lands around the rim of the Pacific Ocean. The '' Pacific Basin'' includes the Pacific Rim and the islands in the Pacific Ocean. The Pacific Rim roughly overlaps with the geological Pacific Ring of Fire.
List ...
. The use of EIFS over
stud
Stud may refer to:
Animals
* Stud (animal), an animal retained for breeding
** Stud farm, a property where livestock are bred
Arts and entertainment
* Stud (band), a British progressive rock group
* The Stud (bar), a gay bar in San Francisco
* ...
-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.
Terminology
In the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
, the
International Building Code
The International Code Council (ICC), also known as the Code Council, is an American nonprofit standards organization sponsored by the building trades, which was founded in 1994 through the merger of three regional model code organizations in th ...
and
ASTM International
ASTM International, formerly known as American Society for Testing and Materials, is a standards organization that develops and publishes voluntary consensus technical international standards for a wide range of materials, products, systems and s ...
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.
The predominant method of EIFS applied today is ''EIFS with Drainage'', which provides a way for moisture accumulated in the wall cavity to evacuate.
EIFS is not
stucco
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 ...
despite often called "synthetic stucco". Traditional stucco is a 20 -40 mm 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.
The technical definition of an EIFS does not include wall framing, sheathing,
flashings,
caulking
Caulk (also known as caulking and calking) is a material used to seal joints or seams against leakage in various structures and piping.
The oldest form of caulk consisted of fibrous materials driven into the wedge-shaped seams between board ...
, water barriers, windows, doors, and other wall components. However, some
architect
An architect is a person who plans, designs, and oversees the construction of buildings. To practice architecture means to provide services in connection with the design of buildings and the space within the site surrounding the buildings that h ...
s have begun specifying flashings,
sealant
Sealant is a substance used to block the passage of fluids through openings in materials, a type of Seal (mechanical), mechanical seal. In building construction ''sealant'' is sometimes synonymous with ''caulk'' (especially if acrylic latex or ...
s, 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" 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.
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.
Some types of EIFS have passed some fire tests that range from resistance to ignitability, that include: ASTM E 119, NFPA 268, NFPA 285. 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.
Composition & types of EIFS

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 base coat which can receive additional layers of mesh for stronger impact resistance. Other types of insulation board can include
polyisocyanurate
Polyisocyanurate (), also referred to as PIR, polyol, or ISO, is a thermoset plastic typically produced as a foam and used as rigid thermal insulation. The starting materials are similar to those used in polyurethane (PUR) except that the proport ...
.
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
Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a ...
(EPS) which is secured with an adhesive or mechanically to the substrate.
*
Glass-fiber reinforcing mesh embedded in the base coat
* 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.
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
Oriented strand board (OSB) is a type of engineered wood, formed by adding adhesives and then compressing layers of wood strands (flakes) in specific orientations. It was invented by Armin Elmendorf in California in 1963. OSB may have a rough and ...
(OSB) or
plywood
Plywood is a composite material manufactured from thin layers, or "plies", of wood veneer that have been stacked and glued together. It is an engineered wood from the family of manufactured boards, which include plywood, medium-density fibreboa ...
). 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
Tyvek () is a brand of synthetic flashspun high-density polyethylene fibers. The name ''Tyvek'' is a registered trademark of the American multinational chemical company DuPont, which discovered and commercialized Tyvek in the late 1950s and e ...
or
felt paper
Bituminous waterproofing systems are designed to protect residential and commercial buildings. Bitumen (asphalt or coal-tar pitch) is a material made up of organic liquids that are highly sticky, viscous, and waterproof. Systems incorporating bit ...
. 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
Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are ...
. 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.
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
A journeyman is a worker, skilled in a given building trade or craft, who has successfully completed an official apprenticeship qualification. Journeymen are considered competent and authorized to work in that field as a fully qualified employee ...
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
Fault tolerance is the ability of a system to maintain proper operation despite failures or faults in one or more of its components. This capability is essential for high-availability, mission-critical, or even life-critical systems.
Fault to ...
).
Marketing of EIFS & the EIFS industry
EIFS account for about 10% of the US commercial wall cladding market. 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.
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.
References
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Building materials
Building insulation materials
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