What is EIFS?

EIFS stands for Exterior Insulation and Finish Systems. The product is also called synthetic stucco, and refers to a multi-layered exterior finish that's been used in European construction since shortly after World War II, when contractors found it to be a good repair choice for buildings damaged during the war. The majority of repairs to European buildings were to structures constructed of stone, concrete, brick, or other similar, durable materials. Today IFS provides insulation, weatherproofing and a finished surface in a single integrated product. There are various types of EIFS and several ways of installing it, but EIFS is usually applied onto the outside face of exterior building walls, in a series of steps, by professionals.


There are many colors and surface textures available with EIFS. EIFS can also be made into carved or contoured "shapes", which give a wall a decorative effect and "shape".


EIFS in North America
North American builders began using EIFS in the 1980's, first in commercial buildings, then applying it as an exterior finish to residences--mostly wood frame houses--using the same techniques that had been successful in Europe.


There are three layers to EIFS


Inner Layer Foam insulation board that's secured to the exterior wall surface, often with adhesive.


Middle Layer A polymer and cement base coat that's applied to the top of the insulation, then reinforced with glass fiber mesh.


Maintaining EIFS


• Any opening, such as door and window frames and the areas around flashings, must be sealed to prevent water from seeping behind the EIFS.

• Gutters should be kept clean and positioned to drain away from the house.

• Foam should not extend below grade.

• Items that penetrate the stucco must be sealed.


In other words, no moisture should be able to seep behind the EIFS.


Signs of EIFS Problems


• Mold or mildew on the interior or exterior of the home.

• Swollen wood around door and window frames.

• Blistered or peeling paint.

• Cracked EIFS or cracked sealant.


EIFS Today


Newer EIFS systems include a drainage arrangement to help keep moisture from being trapped behind the covering. Ask a trusted home builder for details about contemporary EIFS.  EIFS before 2000 was a barrier system, meaning the EIFS system 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 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) have evaluated the 5 life cycle stages of the environmental impact of EIFS. The test compares EIFS, brick, aluminum, stucco, vinyl, and cedar. Conclusion, EIFS saves money in construction costs, is greener and has energy efficient operation, and is the most environmentally responsible material tested. EIFS is the superior cladding in all phases of building construction. The Next Generation of EIFS has overcome problems of the past through extensive testing.


EIFS must be purchased from an EIFS distributor. The manufacturer or distributor trains applicators and issues certificates stating that the applicator has been properly trained. It is the responsibility of the distributor to ensure that EIFS is sold only to those certified applicators.


Deviations from Industry Standard guidelines during installation, is likely the largest contributor to EIFS cladding problems.  EIFS application requires the strict observance of manufacturer recommended specifications and guidelines, and involves meticulous workmanship and attention to detail. When improperly applied, the EIFS cladding does not perform its intended function and can allow water to infiltrate behind the cladding, where it becomes trapped




The problem we face now is, sometimes an individual contractor may fail to fully follow the manufacturer's installation guidelines.  Often times only a portion of the guidelines are followed, materials from different manufacturers are inter-mixed, etc.  This can allow moisture into the wall system.  Once the moisture is in it can't get out, which can lead to wood rot.  Some of the more common installation “short-cuts” are listed below:


  • Foam insulation placed below grade. Prior to recent building code changes, the foam board insulation used in EIFS was placed on the wall below grade. It was discovered that foam in contact with the ground causes conditions conducive to pest infestations (termites, carpenter ants, etc.). With EIFS-clad homes, the visible evidence of infestation is blocked from view by the exterior siding. In fact, the exterior siding typically looks pristine and shows no signs of any problems. Behind the EIFS cladding, pests can live in a protected environment and then establish themselves inside the home. 
  • Another problem with placing the foam below grade is the ability of water vapor to migrate upwards through the foam. When the temperature rises at the transition from masonry to wood, the water vapor condenses and causes water to settle on the sill plates and exterior band joist. If this water does not evaporate quickly, wood rot can set in and decay the structural members of the home.
  • Improperly flashed & caulked windows.  Window leaks account for the majority of water damage in EIFS houses. The EIFS itself isn't usually leaking; instead, water is entering between the window and the EIFS, or the window itself is leaking water. The solution requires a window flashing that works, as well as a correctly detailed joint between the window and the EIFS wall. Wherever a window, a door, or an electrical or plumbing fixture interrupts the EIFS surface, a proper joint must be constructed, that integrates a reliable flashing into the secondary weather barrier.
  • A very important component that is often missing in window detailing is the backer rod.  The backer rod serves two functions: First, it prevents the caulk bead from adhering to the back of the joint, allowing the caulk to flex in response to thermal expansion and contraction and other building movements. If the backer rod is omitted, the caulk will adhere to the back of the joint as well as the sides, limiting its ability to stretch and guaranteeing premature failure. Second, it controls the thickness of the finished application of caulk, which should ideally be about half as thick as it is wide. More often than not, though, the caulk and backer rod are never applied at all. It is important to keep in mind that no residential windows are waterproof, they are designed and manufactured to a water-resistant standard. The very best windows allow some water into the wall cavity through their own joints, and “construction grade” windows may leak a great deal. The quality of windows installed with the EIFS is directly related to the amount of water that will infiltrate. For example, wood windows perform poorly, while welded seam vinyl windows perform substantially better than other window types. EIFS homes cannot be made totally "water proof", and windows will leak. Regardless of how well the backer rod/sealant method seals the joints between window and the edge of the EIFS wall, windows will leak at some point (even those caulk joints made under laboratory conditions by EIFS industry engineers will eventually fail).
  • Flashings missing or improperly installed. are an important element in protecting your house from leakage, and should be utilized to properly direct water away from the structure.  Some of the more common locations where they are required are: deck ledger boards, kick-out flashing at roof / wall intersections, at window and door heads, headers and other horizontal surfaces, etc.  All too often, flashings are not installed, or installed improperly.
  • Roof termination. EIFS should be held off of roof a minimum of two (2) inches and backwrapped.
  • Expansion joints at dissimilar materials. Expansion-joints should be used where EIFS terminates, or meets a dissimilar material. The typical expansion joint is a flexible, watertight joint utilizing, backer rod and sealant. Expansion joints are typically 1/2 inch in width.
  • Backwrapping. Where the foam substrate terminates, it should be backwrapped, in order to provide for proper protection of the foam. Backwrapping also provides for improved attachment of the substrate to the sheathing.
  • Horizontal Surfaces: Trim Bands Quoins. There should be no horizontal (flat) surfaces. All surfaces should slope away from the structure.


An EIFS applicator is responsible for the application process-attaching the foam insulation to the substrate, applying the fiberglass mesh, embedding the fiberglass mesh with base coat and applying a finish coat. EIFS installers have little control over construction details designed to prevent water intrusion into wall cavities from roofs, even including those details which are required by some state building codes and by the specifications of the EIFS manufacturers. Many details outlined by manufacturers require the services of other tradesmen. A typical EIFS applicator does not install backer rods and sealant, but should install the EIFS so that it is possible to install these critical components. The builder is responsible for subcontracting the backer rod and sealant components. Flashing around windows, doors, decks, chimneys and roofs is the responsibility of the builder and his roofer. Unless the builder required the roofing subcontractor to install step flashing and (EIFS required) kickouts, it probably was not done.


The applicator should recognize improper flashing and not continue the application process until the problem is corrected.  Unfortunately, this also slows down the overall building process. . .costing the home builder extra money.  It doesn’t take an applicator long to recognize that an unhappy home builder may NOT call him to bid on the next project.


Lack of Care and Maintenance

The beautiful architectural designs made possible by synthetic stucco systems make these homes very desirable and marketable. It is critical, however, to carefully maintain these systems to prevent water intrusion and deterioration. It is very important that the six following steps be followed to protect your investment.


1.      Annually inspect all sealant around windows, doors, penetrations through the EIFS, EIFS transitions (such as EIFS to brick, EIFS to stone), and stucco terminations (at roof, at grade, at patios or walkways). Arrange for prompt repair of any areas of caulk that is split, cracking, crazing or is losing adhesion. Also, promptly repair any cracks in the EIFS.


2.      Any leaks, cracks, areas of discoloration, mold or mildew should be promptly investigated by a certified EIFS inspector. Repairs should be proper and prompt.


3.      Anytime you make a penetration through the EIFS such as to mount a satellite dish, add shutters, new wiring, cables, plumbing, security systems, etc., the perimeters must be sealed with a quality sealant approved for EIFS.


4.      Modifications, additions or renovations (including roof replacement) to the structure of any kind should be inspected by a qualified EIFS inspector to ensure waterproofing of critical details is properly performed.


5.      Periodic cleaning of the surface is necessary to maintain its appearance and prevent permanent staining. Pressure cleaning equipment must be calibrated to the EIFS manufacturer’s recommended pressure level (low) to prevent damage. Select a firm with experience in cleaning these EIFS systems. There are no products that are totally maintenance free, and EIFS is no different.




Toronto Stucco Contractor - Image 1