As one of the most widely used and readily available building products, Polyiso is a cost-effective insulation option for reducing building energy use and improving the overall service life of roofs and walls.
What Is Polyiso Insulation?
Polyisocyanurate insulation is a rigid, closed-cell, continuous foam board insulation. The foam in the rigid polyiso boards is pressed together so tightly during manufacturing that air and moisture cannot get through the board when installed. Facers are added to the board to further increase the polyiso board’s performance characteristics.
What Are the Benefits of Polyiso Insulation?
Polyiso provides many benefits outside of its excellent thermal characteristics:
High R-value per inch of thickness
Excellent fire test performance
Extensive building code approvals
Cost-effective continuous insulation (CI) solution
Compatible with most wall and roof systems
Dimensional stability
Compressive strength
Moisture resistance
Thinner walls and roofs with shorter fasteners
Long service life
High solvent compatibility
Compatibility with most solvents used in construction adhesives
A wide range of service temperatures
Zero ozone depletion potential
Recycled through reuse
Virtually no global warming potential
QualityMark™ certified LTTR values
Where Can Polyiso Be Used?
Polyiso is a highly versatile form of insulation that provides superior performance in both roof and wall installations.
Roof Applications
Compatible with nearly any commercial roof system, Rmax polyiso can be used with modified bitumen, metal, built-up, ballasted single-ply, mechanically attached single-ply, and adhered single-ply. Polyiso is used in almost 70% of all commercial roof construction because of its durability and excellent thermal performance.
Wall Applications
Polyiso is a popular choice for wall installations due to its ease of installation, durability, and thermal performance. Rmax polyiso’s integrated air barrier and vapor management layers reduce the labor involved during wall construction while resulting in a better finished building. With fewer thermal breaks, the overall wall’s composite R-value will be higher too.
Polyiso works great in continuous insulation installations which are increasing in popularity. ASHRAE defines Continuous Insulation (CI) as “insulation that is continuous across all structural members without thermal bridges other than fasteners and service openings. It is installed on the interior, exterior, or is integral to any opaque surface of the building envelope.” As energy efficiency becomes more important and exterior continuous insulation becomes the standard, polyiso will be the insulation of choice for many of those installations.
Common Polyiso Facers
One great aspect of polyiso rigid boards is that they can be easily faced during manufacture to boost their performance. Sandwiched between layers of facing, polyiso becomes a truly high-performance composite material. Some common facer options include:
Non-asphaltic, fiber-reinforced organic felt facers. Standard facers for roofing, these facers provide long-lasting performance and increase the insulation’s durability, chemical, and mold resistance.
Foil facers. These facers work to increase the insulation's thermal performance, maintain dimensional stability, and decrease the likelihood of water absorption or water vapor transmission.
Is Polyiso Safe for the Environment?
Polyiso foam is made through a chemical reaction that mixes the components together with a fire retardant, a blowing agent, and small amounts of catalyst. Mixing these compounds together causes a heat-generating reaction to occur which boils the blowing agent, pentane. The boiling of the pentane causes the foam to expand and create gas-filled cells throughout the foam board. These gas-filled cells make polyiso rigid boards lightweight with low thermal conductivity.
One of the reasons pentane is used as the blowing agent for polyiso foam boards is because of its safety. Pentane has no ozone-depletion risk and has very little global-warming potential. In the past, blowing agents were used that damaged the environment, but those have all been replaced with more environmentally-friendly options.
Does Polyiso Have a High R-Value?
Polyiso has a high R-value per inch when compared to other insulation products, see the chart below. This allows Polyiso products to deliver more energy savings potential for buildings than other materials of the same thickness.
R-Value Per Inch Comparison
Polyiso has an R-6.5 and the highest R-value per inch when compared to other insulation.
What is LTTR?
Based on consensus standards in both the U.S. and Canada, Long Term Thermal Resistance (LTTR) is a scientifically-supported method of calculating the 15-year, time-weighted average R-value of roof insulation. All Polyiso manufacturers in the Polyisocyanurate Insulation Manufacturers Association (PIMA) have adopted the LTTR method as the exclusive means to measure thermal performance of permeable-faced Polyiso roof insulation. PIMA Polyiso manufacturers have certified LTTR-value products verified by the QualityMark™ Program.
What is QualityMark™?
The PIMA QualityMark™ Certification program is a voluntary program that allows Polyiso manufacturers to obtain independent, third-party certification for the Long Term Thermal Resistance (LTTR) values of their Polyiso insulation products. Polyiso is the only insulation to be certified by this unique program for its LTTR value. The program is administered by FM Global and was developed by the Polyisocyanurate Insulation Manufacturers Association (PIMA) based on work done at Oak Ridge National Laboratory and CAN/ULC- S770. Click here to view the QualityMark™ Brochure.
Easier on the Environment and for Installation
Polyiso boards have superior R-values, so less material is needed to get the same amount of thermal performance when using polyiso. These characteristics make polyiso a better choice throughout a building’s lifecycle.
Easier on Shipping
High-density polyiso boards take up less room, making them easier to ship and move around. Polyiso boards take up less space, they are easier to ship on trucks, store in warehouses, and store on the job site.
Easier on the Job Site
The individual boards weigh less than other insulation types, so boards can be moved around much more easily. Less manpower is needed to move insulation throughout the job site, keeping projects moving ahead on schedule.
Easier on the Building
The significantly lighter weight of rigid polyiso boards lowers the overall weight that the structure itself must bear. Compared to gypsum boards, polyiso reduces the total dead load that the building sees, which can decrease costs from structural loads.
Easier on the Environment
Not only is polyiso now made from blowing agents that do not damage the ozone layer, but the overall global warming potential of polyiso is some of the lowest in the industry. Polyiso’s incredible performance also reduces the amount of energy the building needs to operate for the life of the building. Many of the raw components that go into the rigid boards during manufacture are recycled raw materials that further reduce polyiso’s impact on the environment. Polyiso is gentle on the environment throughout its lifecycle.
Whether for commercial, residential, or specialty construction, Rmax polyiso is ready to meet your application’s needs. High-performance insulation in a building’s roof or walls leads to decades of energy savings while being economical for construction and easy on the environment. Learn more about all Rmax has to offer by reaching out to our team of insulation experts today.