Product Decision: Building Science

The Principles of Building Science

Practicing building science, also known as a “systems approach,” means accounting for the ways all building components interact, including the foundation, walls, roofs, doors, windows, insulation and mechanical systems. Doing so is critical to optimise building performance and prevent building failures. Last but not least the building occupants must be educated to behave properly to limit energy losses; the most optimised building with the best insulation will be useless if the occupants do not respect the environment. The principles of building science include:

  • Creating a continuous air barrier combined with proper mechanical ventilation
  • Providing thermal resistance and limiting heat bridges
  • Managing moisture
  • Improving indoor air quality
  • Using appropriate heating systems

Icynene spray foam insulation addresses all of these principles to help building and design professionals practice building science techniques with ease. The benefits are verified through extensive research and testing performed on all Icynene products worldwide.

How Icynene Spray Foam Insulation Plays a Vital Role

Building scientists are now stressing the importance of air barriers like Icynene spray foam insulation in building design and construction. This is partly because many buildings constructed in the past had no air barriers and experienced major failures in terms of moisture damage and mould caused by condensation, which stemmed from air leakage.

In addition, research shows that without an air barrier, insulation cannot deliver optimal energy efficiency or comfort. This is why blower door tests are commonly required to measure air tightness in new or renovated buildings.

Limits of U Value

U value measures insulation’s ability to limit conductive heat flow (heat that is transferred through it). But the primary method of heat transfer is not conductive heat flow — it’s air leakage, which can account for up to 40% of a building’s energy loss.

In addition, U value only does so much to prevent even conductive heat flow. Beyond a certain point, improving insulation U value makes very little difference, if any. Above a certain thickness of insulation material the heat flow reduction due to conduction reaches a plateau. In fact, the cost of improving U value alone can actually far outweigh the energy savings that result, meaning it will take much longer to break even.

Therefore, the best way to increase efficiency is not merely to improve U value, but rather to combine U value with an air barrier. Icynene spray foam insulation provides both in a single step.


Spray Foam Insulation and the need of vapour barriers

Approximately 99% of the water vapour that travels through a building envelope enters through air leakage. Icynene spray foam insulation controls air leakage so effectively that a separate vapour retarder is often not necessary. We have conducted extensive WUFI modelling research and our approved contractors can determine whether or not a vapour barrier is required. We do not generally recommend the use of a vapour barrier since our foam is open cell, it lets humidity out. Exceptions include places with high interior relative humidity, such as swimming pools and poorly ventilated areas. When a separate vapour retarder is needed, it should be applied to the warm side of the wall.



Learn about the important contributions of Icynene products to sustainability.