Understanding Exterior Insulation and Finish System (EIFS) and Stucco Repair for Commercial Buildings

Adam Robinson | Nov 04, 2021

Minimizing energy use is a top priority for building owners, maintenance staff, and building occupants. Improper energy use can have many origins, including failure to shut off appliances, running lighting systems during vacancy hours, and excessive use of the heating, ventilation and air conditioning or refrigeration (HVAC/R) systems. Part of this comes down to the quality of the exterior insulation and finish system (EIFS). While building occupants can make meaningful improvements in interior energy use, the biggest drivers of energy use in these buildings come from the HVAC/R systems. This is simply due to the increased energy use needed to keep the interior comfortable and effectively shielded from the heat loss or gain of the outside world. 

In the U.S., the age of the building is directly related to its energy-efficiency needs. According to the U.S. Energy Information Agency’s “2018 Commercial Buildings Energy Consumption Report, more than half of all buildings in the U.S. were built between 1960 and 1999. Among these buildings, the main culprits of energy consumption include space heating (83%) and cooling (78%). More troubling, out of all potential energy efficiency improvements, only LED lighting had increased in use since 2012. While this data is already three-years-old, it’s still the most recent year for which the study was commissioned. As a result, it’s a safe assumption that improving building energy efficiency comes down to recognizing the issues in existing buildings and improving their ability to reduce energy use. That also implies it’s time to rethink the building exterior and how addressing exterior insulation and finish system problems could lessen the total heat gain or loss of these buildings.

For that reason, this guide will explore all aspects of exterior insulation and finish systems, including:

  • Their differences from what most think of in terms of insulation.
  • What exterior insulation really means.
  • The benefits of exterior insulation and finish systems.
  • The top performance considerations when choosing or repairing such systems.

What Is Commercial Building Insulation and What Is an Exterior Insulation and Finish System

Commercial building insulation is all about creating a barrier between the building’s interior and exterior to reduce heat gain or loss. As further explained by the U.S. Department of Energy, “Most common insulation materials work by slowing conductive heat flow and convective heat flow. Radiant barriers and reflective insulation systems work by reducing radiant heat gain. To be effective, the reflective surface must be in contact with an air space.

“Regardless of the mechanism, heat flows from warmer to cooler areas until there is no longer a temperature difference. In your home, this means that in winter, heat flows directly from all heated living spaces to adjacent unheated attics, garages, basements, and especially to the outdoors. Heat flow can also move indirectly through interior ceilings, walls, and floors—wherever there is a difference in temperature. During the cooling season, heat flows from the outdoors to the interior.”

Still, the exterior itself becomes part of the insulating materials. This is where the questions of what is exterior insulation and finish system and how is it different get confusing. The exterior insulation and finish system refers to a class of non-load bearing materials that adhere to the exterior of the building, provide insulation and keep moisture out of the building. Unlike standard commercial insulation, it’s a more modern approach to leveraging lighter materials that maximize resistance to the elements. Yet, the goal of any type of insulation remains the same—improve occupant comfort, maintain integrity of building materials, and avoid water infiltration. 

Now, it’s also important to realize that stucco and exterior insulation and finish system are two different aspects of a modern building exterior. Stucco may possess qualities similar to EIFS panels and materials, but stucco is also subject to spalling, cracking, or other degradation. EIFS may contain both premanufactured panels or be applied in a manner similar to traditional stucco. However, the ingredients going into the applied cementitious mix are slightly different in exterior insulation and finish system. Still, stucco can be part of an effective EIFS. Therefore, knowing the different types of building insulations used and their nuances can make a difference in knowing when to replace or repair such materials and how to maximize the longevity of your building exterior.

The Types of Commercial Building Insulation

The best type of commercial building insulation to use depends on the needs of the building, defined by the engineer responsible for the design and repair of the building. In general, there are a few different types of commercial building insulation to consider, including:

  • Radiant barriers are generally waterproofed to reflect heat by using a shiny surface facing the direction where the heat comes from, such as exterior shiny metal surfaces that reflect the sun’s rays.
  • Batt insulation is among the most common types of heat barriers used in construction in which irregularly shaped materials are pushed into wall spaces to trap air between fibers and prevent heat loss. 
  • Blown-in insulation is a non-water resistant, loose-fill insulation consisting of fiberglass-like material placed within the walls of a building.
  • Spray foam insulation is similar to blown-in insulation, but it’s also an excellent choice for adding insulation to difficult-to-reach places and cracks in existing structures that need repairs.

Regardless of which system is chosen, their biggest function comes down to their use in conjunction with the exterior surface materials that waterproof the structure and add to a wall’s insulating capacity. This is where the true nature of exterior insulation and finish systems becomes most evident. In terms of EIFS, the most types of systems available include:

  • A one-coat system with a metal lath or mesh panel that serves to strengthen and hold the finishing materials while they dry to a firm, solid cladding. This may include a singular lath and a single coat of cementitious materials, such as a one-coat stucco paste, that’s applied to provide a waterproof structure and heat-resistant barrier to the exterior of the building, which is likely to come with more exterior insulation and finish systems problems than a more advanced, polymer-included mix.
  • Polymer-based systems rely on polymers, such as polystyrene or poly, that adheres the substrate, such as stucco, to a fiberglass mesh embedded in the material. The idea is to use the polymer as glue to hold both the interior insulation and exterior insulation together in a way that extends durability without sacrificing the quality of heat resistance afforded by the materials. 
  • Water-managed exterior insulation and finish systems contain a drainage cavity to ensure all moisture exits the wall without causing damage to the structure. This is of particular importance in climates with high annual precipitation rates or those subjected to frequent types of water exposure beyond the rain, such as ocean spray in coastal areas or snow buildup and melting in colder areas.

Benefits of Exterior Insulation and Finish Systems

The benefits of modern exterior insulation and finish systems are world-renowned. According to the EIFS Industry Members Association (EIMA), “chief among these are superior energy efficiency and virtually unlimited design flexibility.” However, that barely scratches the surface of their real value-added benefits including:

  • Reduced air infiltration. Using a modern EIFS can help reduce air infiltration by up to 55%. 
  • Reduced water infiltration. Since a quality EIFS system and repairs leverage waterproof additives and coating to maximize their integrity, they also have an improved water resistance measure. 
  • Improved building energy efficiency. Combining both air and water resistance lends itself to improved energy efficiency through reduced heat gain or loss. Also known as the “R-value” of a building, the right type of EIFS can dramatically improve the value of a building and reduce the total cost of ownership, especially with relation to energy use.
  • Adherence to new building codes. Part of the benefit of using an EIFS to achieve a higher R-value includes increased adherence to applicable building codes specified within the ASHRAE Standard 90.1-2010. This effectively means that these buildings have successfully improved integrity without resulting in a higher cost or risk to building occupants, lessening the total cost of ownership along the way. 
  • Possible reduced capacity needs of heating and air conditioning systems. Improving the energy efficiency of a building through fewer exterior insulation and finish systems problems also possesses a few indirect benefits. Since the building is less likely to experience heat gain or loss, the total heating or cooling capacity of the HVAC system may be lessened. As a result, the cost of purchasing, installing, and maintaining the HVAC systems in use decreases, further adding value to the building. 
  • Increased durability. A quality EIFS is widely flexible across colors and materials, making it an ideal solution for customized building exteriors. Additionally, the added strength and durability of the materials result in fewer aesthetic maintenance needs (in other words, they require less repainting). This occurs as the layers beneath the exposed exterior are the same color as the exterior, resulting in the appearance of the same color even when slight damage occurs. However, this further reinforces the need for expert inspections and guidance in identifying and making repairs too. 
  • Resistance to dirt, mildew, and mold. The materials used in EIFS are also resistant to dirt, mildew, and mold, deriving from their impermeability to the elements. 
  • Impact resistance. The durability of an EIFS comes with another added benefit, impact resistance. Impact resistance may seem trivial, but over time, insects, birds, and regular care, including window washing or exterior activities, may result in multiple impacts that could cause damage. By following the specifications for each EFIS at the time of construction or repair, building owners and managers can rest assured that their exterior will be in top-notch shape for decades to come. 
  • Resistance to cracking and premature damage. As previously noted, traditional stucco exteriors are prone to crack. This can be lessened through routine applications of sealants and using fiberglass-reinforced cementitious materials for the stucco. However, a comprehensive EIFS that leverages polymers possesses added tensile strength that resists cracking and premature damage. This goes back to all the benefits listed above. 
  • Fire resistance. All buildings must pass rigorous fire resistance tests according to building codes, and this is especially true among multistory buildings. Leveraging an EIFS adds another layer of fire resistance that can help to prevent ignition of building materials when subjected to potential risks, such as hot embers coming from nearby wildfires or even the magnifying effect caused by the sun’s reflection off windows. Together, an EIFS creates a more indestructible, fire-resistant structure that can pass all building inspections and add value to the building throughout its usable life.

Considerations in the Performance of Exterior Insulation and Finish Systems

With all the information on the benefits of the right approach to exterior finishing, it sounds like a one-and-done solution. However, there are a few considerations building owners need to take when assessing the need for such systems. These include the following:

  • Thermal performance (heat resistance of the EIFS).
  • Moisture protection ((the ability to prevent water infiltration).
  • Finish durability (how often repairs may be necessary).
  • Expansion joints for EIFS applied over wood structures.
  • Using flashings to divert water away from the EIFS, especially where the roof or decks touch the EIFS. 
  • Type of base coat used in new construction and repairs. 
  • Type of finish coat applied and its required frequency for reapplication.
  • Potential integrity problems arising from damage due to ropes, cables, or other exterior activity, including window washing.

Exterior Insulation Versus Stucco

Understanding the differences between an exterior insulation and finish system and stucco can be confusing. Yes, all stucco is part of an exterior insulation system. However, an EIFS is an acrylic product that is used beneath the stucco to create a moisture barrier and improve the integrity of the building. Meanwhile, traditional stucco siding is a cementitious mix containing Portland cement, sand, limestone and water. Traditional stucco is heavier and requires more care than a modern EIFS that leverages polymers for improved tensile strength and is easier to repair as well. 

Get on the Right Track With Expert Guidance

Choosing the right exterior finish for your building must not be a last-minute process. The right finish can successfully draw in more building tenants and customers. As explained by BUILD magazine, a quality exterior adds a sense of professionalism to your business, improves safety and security, safeguards against complaints, prevents degradation, and lessens your total cost of ownership. With so much at risk in a world marred by liability concerns, building owners and managers need to ensure their exterior is not left to the elements. Instead, they need to work with an expert in building exterior construction, maintenance, and design to ensure the exterior insulation and finish system is of the best quality and adds value to your business.

Valcourt Building Services is the right company for that need. Connect with Valcourt Building Services to schedule an inspection or repair of your EIFS today.

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