Insulation plays a pivotal role in a building’s energy efficiency and occupant comfort. Particularly in below grade applications, those involving construction elements located below the ground level, the choice of insulation material is crucial. Below grade, insulation is exposed to higher pressures from soil and liquid water while still being required to slow heat transfer from a building to its surroundings.
Polyisocyanurate, commonly known as polyiso, stands out as a preferred material for below grade insulation due to its unique properties and advantages. Below grade insulation applications can be demanding, but polyiso is up to the challenge.
What is Polyiso Insulation?
Polyiso is a type of rigid foam board insulation that is known for its high R-value per inch of thickness. The high R-value per inch reflects polyiso’s impressive ability to slow heat transfer from one environment to another. Polyiso is a product of a continuous lamination process that forms a closed-cell, thermally resistant core, typically sandwiched between two facers. The facers can be of various types, including aluminum and coated glass, which enhance the insulation's performance in different environments. Polyiso is durable, high-performing, and easy to install.
Advantages of Polyiso in Below Grade Applications
1. High Thermal Efficiency
Polyiso insulation boasts a high R-value, which measures the material's ability to resist heat flow. The high R-value per inch means polyiso provides excellent thermal insulation to reduce energy costs and improve overall energy efficiency in buildings. The high R-value per inch property of polyiso also means that less material is required to achieve the same R-value than other materials.
2. Water Resistance
One of the key concerns in below grade applications is moisture control. Polyiso's closed-cell structure inherently resists water absorption, which makes it an ideal choice for damp environments. This feature is further enhanced when polyiso is equipped with water-resistant facers like aluminum foil that provide an additional barrier against moisture penetration.
3. Compressive Strength
The insulation material in below grade applications must withstand soil pressure without significant compression, which could compromise its insulating properties. Polyiso demonstrates high compressive strength that is capable of resisting the lateral pressure exerted by soil, to maintain its shape and effectiveness over time.
4. Environmental Sustainability
The environmental impact of building materials is a significant and growing consideration. Polyiso is noted for having a lower environmental impact compared to other insulation materials with products like RMAX® Below Grade using 90% less GWP blowing agents than comparable next-generation XPS products.
Polyiso features a high R-value which allows for thinner applications and fewer truckloads to the job site for reduced material usage and transportation-related costs. Moreover, polyiso often includes eco-friendly facers that increase building performance and minimize impact to the environment.
5. Versatility and Ease of Installation
Polyiso insulation is versatile and can be used in various parts of a building’s envelope, including roofs, walls, and foundations. Its lightweight nature and ease of cutting to size make it a user-friendly option for contractors. This versatility extends to its compatibility with different building designs and requirements.
6. Cost-Effectiveness
Despite its superior properties, polyiso remains a cost-effective solution for below grade insulation. Its durability and long service life mean reduced maintenance and replacement costs over time, which contributes to its overall cost-effectiveness.
7. Fire Resistance and Safety
Safety is paramount in construction, and polyiso scores high in this regard. It exhibits excellent fire test performance and meets extensive building code approvals.
Unlike thermoplastic insulation materials like EPS and XPS which melt and drip when exposed to a flame, polyiso is classified as a thermoset. When exposed to a flame, polyiso chars and retains its shape which helps to minimize the spread of fire damage. This makes it a safe choice, particularly in residential and commercial buildings where fire safety is a critical concern.
8. Integration with Building Systems
Polyiso is compatible with most wall and roof systems, so it is a go-to insulation choice for a variety of construction projects. Its ability to integrate seamlessly with other building materials and systems adds to its appeal in the construction industry. Polyiso can be quickly installed to create a seamless, high-performing layer of below grade insulation.
9. Increased Occupant Comfort
Polyiso insulation helps avoid creating cool, damp below grade spaces. By minimizing heat transfer and moisture intrusion, the interior spaces below grade stay warmer with an appropriate amount of humidity. The polyiso insulation also helps the building’s walls and foundation retain heat which keeps the space comfortable and reduces the risk of condensation on the interior surfaces.
Polyiso - Ready for the Challenge!
Polyiso insulation offers many different advantages for below grade applications, which makes it a superior choice for builders and architects. Its high thermal efficiency, water resistance, compressive strength, compatibility with various building systems, and many other advantages make it an all-around excellent choice for any below grade insulation needs. Polyiso is able to perform in any part of a building’s envelope. By choosing polyiso, builders can ensure enhanced building performance, durability, and sustainability.