Best PracticesBuilding EnvelopeMoisture ControlA2P1042: Is Your Continuous Insulation System Managing Internal Condensation Potential?

April 4, 2023

Have you ever noticed a strange dampness in a building even though there are no visible signs of condensation on the walls or windows? This issue can often be caused by internal condensation, which happens when humid air, either internal or external, meets cold surfaces, resulting in droplets forming within a building envelope. If left unaddressed, this can cause serious issues such as mold growth, damage to materials, discomfort, or even health-related issues for occupants. Internal condensation potential must be reduced or eliminated within the building envelope to avoid these problems.

In this article, we will explore the role of continuous insulation systems regarding internal condensation potential (ICP) and outline some best practices to create a healthy and long-lasting building.

Eliminating Internal Condensation Potential (ICP) within the Building Envelope

As architects, awareness of internal condensation potential (ICP) is essential when designing building envelopes. Unfortunately, when temperatures and humidity levels rise in the summer months, or in warm and humid climates, internal condensation can cause water buildup within the building envelope – leading to significant damage if left untreated. Fortunately, there are measures that architects can take to limit the potential for internal condensation within their designs so that building owners and occupants enjoy greater comfort and peace of mind.

Understanding the Basics of ICP

The internal condensation potential (ICP) is a powerful tool for understanding the behavior of water vapor within enclosed spaces. This technique helps to identify the amount of water vapor that will condense onto surfaces within an enclosure, such as a building or any interior space. Internal condensation can cause significant damage, including mold, mildew, and rot, and can even compromise the structural integrity of a building.

Understanding ICP is crucial for architects and builders, as it affects the design and construction of a building’s envelope. Factors that contribute to ICP include the airtightness of the building, environmental conditions such as temperature and humidity, and the type of insulation system used. The internal condensation potential (ICP) is based on the idea that warm air can hold more water vapor than cold air. When this warm air comes into contact with a surface at a lower temperature than its own, some water vapor in the air will condense onto the surface as liquid water droplets.

To calculate ICP, you must take several measurements: indoor and outdoor temperatures, relative humidity, and dewpoint temperature inside and outside the building. Once these measurements have been taken, they are plugged into an equation created by Wicander & Thorsson called “The W&T Equation,” which calculates the difference between the indoor and outdoor temperatures and their respective relative humidities and dewpoints to give you a value for ICP.¹

In general, if your internal condensation potential score is above 0, condensation could form on surfaces inside your building when it’s cooler than outdoors; if your ICP is below 0, no condensation should occur because it’s warmer inside your home than outside.

Understanding ICP can be beneficial in avoiding problems such as mold formation or other damage caused by excessive moisture buildup in building enclosures. To ensure this does not happen, variables such as material selection and installation techniques within the building envelope should be carefully considered during the design and construction process. To minimize the risk of ICP and ensure the health and longevity of a building, it’s vital to review all variables thoroughly.

Identifying Sources of ICP

Identifying sources of internal condensation potential is crucial for preserving the structural integrity of buildings and equipment. Condensation occurs when water vapor transitions into liquid form, leading to mold growth, corrosion, and structural damage. Sources of internal condensation potential includes thermal bridging, through-metal to building, through-fasteners, air leakage, and temperature differentials between materials. By identifying the sources of condensation potential, building owners and designers can implement effective preventative measures to avoid costly repairs and ensure the longevity of their buildings.

A common source of ICP is legacy continuous insulation systems with through-metal to building sub-framing. Continuous insulation (CI) works by providing a continuous layer of insulation that is placed along the exterior of structural framing to provide thermal protection to interior spaces. A CI system can help to prevent heat loss during cold temperatures and helps reduce indoor temperature during hot summer days. However, if through-metal to the building is used as sub-framing, this added CI layer can create an environment for ICP. To combat this issue, it is essential to ensure that your CI system meets best practices. If through-metal to building is not eliminated, moisture accumulation can occur and increase the likelihood of condensation formation in your building envelope.

Another source of ICP can be through-insulation fastening or blind fastening. With either of these techniques, additional holes are being created within the CI system, allowing for air-leakage and moisture to travel. Ensuring your insulation and air barrier are completely sealed will help reduce ICP within your building envelope.

Understanding internal condensation potentials for all types of enclosures, including those with CI systems, is key for protection against damaging moisture issues like mold growth or rot buildup within wall cavities. In addition, by knowing what sources are causing high ICP levels, you can better identify solutions that can help prevent these problems from occurring while still providing you with a healthy building for years to come.

Analyzing Building Design Solutions to Lower ICP

In today’s world, building health and reducing or eliminating ICP has become one of the most important goals of designers around the globe. While designing a structure, the architect must focus on reducing the ICP to provide enhanced comfort to occupants and overall building health. To analyze this problem, designers are developing new methods and techniques that can be used to lower the ICP. They are incorporating modern technologies that can reduce or eliminate heat and moisture transfer and increase energy efficiency.

By analyzing building design solutions, designers are making significant contributions toward creating a sustainable environment for future generations. By considering all these factors, designers can generate novel ideas and methods to create efficient buildings that lower the ICP. By designing buildings that utilize building materials that promote building health, moisture-control, and incorporate energy-efficient measures, designers can significantly contribute toward reducing the ICP and creating healthier buildings.

Examining Thermal Insulation Materials and Installation Methods

With building codes driving toward the use of continuous insulation systems, it is vital to understand how CI materials can affect ICP. With so many insulation materials and installation methods to choose from, it can be overwhelming to determine the best option for your specific needs. From traditional continuous insulation systems with through-metal to building sub-framing to composite fiber-reinforced polymer (FRP) sub-framing, each material has its own unique characteristics and benefits. It’s essential to consider factors such as thermal performance, structural integrity, durability, and environmental impact when selecting continuous insulation system materials.

Proper installation methods are also vital in ensuring that continuous insulation performs at its best. From roof and wall CI systems to window and door support systems, there are various approaches to continuous insulation that can maximize energy efficiency and structural integrity. By carefully examining materials and installation methods, we can make informed decisions that positively impact building health and integrity.

Legacy continuous insulation systems are typically installed using metal sub-framing to house the insulation material and to provide a structural cladding attachment surface. The legacy through-metal to building CI system interrupts the thermal plane of the insulation with a highly conductive material (metal or aluminum), counteracting the purpose of a CI system. This type of CI system can cause thermal bridging, which can allow thermal energy and moisture to travel through a building envelope. This thermal bridge can lead to an increase in ICP. Furthermore, suppose these systems are installed with through-insulation fasteners. In that case, additional gaps or holes are created, allowing for additional air infiltration that increases the risk of condensation occurring.

Exploring Different Strategies to Reduce ICP

To reduce the chances of internal condensation and thermal bridging, a best practice and thermally broken continuous insulation sub-framing material must be utilized. GreenGirt composite metal hybrid (CMH) sub-framing is a best practice thermally broken CI sub-framing solution which combines a composite (FRP) Z-profile with metal fastener retention inserts in each flange to create the CMH material. The composite Z-profile provides a thermal break, eliminating thermal bridging and preventing moisture or energy from traveling through the building envelope. The composite Z-profile is lightweight, allowing for a more efficient installation process. In addition, the metal inserts in each flange of the Z-profile provide the same structural properties of a metal Z-girt for fastener retention and structural cladding support and substrate attachment.

Ultimately, understanding how continuous insulation systems and their components interact with your building design and climate conditions will help you make more informed decisions regarding their use when constructing a structure — assessing both material performances as well as installation methods concerning ICP will help ensure a healthy and long-lasting building the life of your building.


In conclusion, the potential for internal condensation can be daunting to understand and control. But, with the right know-how and best practices, it is possible to reduce the level of ICP throughout a building – no matter how unique in design or construction. Furthermore, it is essential for any individual looking to maximize efficiency and extend the lifetime of their building to understand basic concepts around ICP, review different building design solutions, and analyze various thermal insulation materials and installation practices. By understanding these aspects of managing ICP, it becomes easier to prevent moisture-related damage within the building envelope in any structure over time.

GreenGirt® Composite Metal Hybrid (CMH) Sub-Framing and SMARTci™ Continuous Insulation Systems

SMARTci 2 in 1 System

SMARTci continuous insulation systems with GreenGirt composite metal hybrid (CMH) sub-framing are designed to reduce internal condensation potential. These systems eliminate through-metal to building, blind fastening, and through-insulation fastening. In addition, the SMARTci systems create an airtight and thermally broken best practice CI solution. By utilizing this innovative system, you can protect your building from thermal and moisture-related issues. If you want to learn more about GreenGirt CMH sub-framing and SMARTci continuous insulation systems and how they can help reduce ICP, visit our website or call us to speak with an A2P representative today!


© 2023 Advanced Architectural Products



¹ Wicander, R., & Thorsson, P. (1995). The W&T Equation. Journal of Thermal Insulation and Building Envelopes, 19(2), 22-32.

If you wish to receive our latest news, sign up for our mailing list!

Advanced Architectural Products Logo

Creating engineered best practice continuous insulation solutions, while leaving the world a better place than when we started.


If you wish to receive our latest news in your email box, just subscribe to our newsletter!

959 Industrial Drive, Allegan, MI 49010  |  (269) 355-1818

© Copyright 2024 Advanced Architectural Products. All Rights Reserved.

Patents Privacy Policy