Insulation is one of the most critical components of a roof, providing much-needed thermal performance in today’s energy conscious world. Polyiso’s unique benefits, strength and versatility allow it to adapt to a variety of roofing applications.

• Highest R-value per inch
• Outstanding installed cost advantages
• Only roof insulation with third-party certification of thermal performance
• Only high-thermal foam to meet both FM 4450 and UL 1256
• Nationwide availability 
  

Highest R-value per inch of thickness
Inch for inch, polyiso has the greatest energy efficiency performance of any building insulation product on the market. In independent testing, polyiso’s thermal performance has proven to exceed other common roof insulating materials, which means less polyiso is needed to maintain the same R-value. This results in thinner walls and roofs with shorter fasteners, less change in building dimensions to meet a determined R-value and immediate cost savings through a reduction in materials and labor.

Cost effective
There are many studies that illustrate the cost effectiveness of polyiso insulation.  One payback study released by PIMA, the trade association of the polyiso industry, shows that increasing the thickness of polyiso insulation on a roof deck significantly reduces energy costs while providing a positive rate of return on the cost of installation (Polyiso Performs Again). Another study, also conducted by PIMA, shows that polyiso insulation can save tens of thousands of dollars in installed costs when compared to extruded and expanded polystyrene insulation.  (First Cost Study)
 
LTTR-Value
Based on consensus standards in both the United States and Canada, Long Term Thermal Resistance (LTTR) is a scientifically supported way to calculate the 15-year, time-weighted average R-value of roof insulation. Most polyiso manufacturers have adopted the LTTR method as the exclusive means to measure thermal performance of permeable-faced polyiso roof insulation.
            
Using techniques in ASTM C1303, CAN/ULC S770 predicts a foam’s R-value that has been shown to be equivalent to the average performance of a permeably faced foam insulation product over 15 years. In Canada, this method is used as the design R-value. The LTTR method provides users, specifiers and designers with many advantages including:

• A technically supported, more descriptive measure of the long-term thermal resistance of polyiso insulation—a 15-year time—weighted average;
• An advanced test method, based on consensus standards in the United States and Canada;
• A method that applies to all foam insulation with blowing agents other than air, such as polyiso, extruded polystyrene and polyurethane; and
• A better understanding of thermal performance of foam. 
  

Click here to view the LTTR Fact Sheet.

Superior performance in fire tests
Polyiso passes both the ANSI UL 1256 and FM 4450 fire tests without a thermal barrier. Polyiso, a thermoset material, stays intact during fire exposure in the ASTM E84 or “Tunnel Test.” It forms a protective char layer and remains in place during this test, thereby meeting all building code requirements and contributing to a fire-safe building. For more information on polyiso’s performance in fire tests, consult the Technical Bulletins section. (Fire Performance in Roof Systems) (Fire Test Definitions) (Class A and Class 1 Roof Assemblies Are Not the Same)
 
Polyiso offers compressive strength
Compressive strength refers to the ability of a rigid foam board to resist deformation and maintain its shape when subjected to a force or load. Common construction applications require compressive strength adequate for polyiso to maintain its shape during installation as well as during use. Polyiso insulation boards are available in a range of compressive strengths. The ASTM Specification of Polyiso Insulations, C 1289, states that all polyiso products should have a minimum stated compressive strength of 16 psi.

For more information on polyiso’s compressive strength, please consult Compressive Strength.
 
Environmentally responsible
All polyiso insulation manufactured by PIMA members, the trade organization representing polyiso manufacturers, utilizes an U.S. EPA compliant hydrocarbon-based blowing agent which has zero Ozone Depletion Potential (ODP) and virtually no Global Warming Potential (GWP).  Polyiso insulation is the answer to CFC and HCFC free specification requirements.
 
Other unique properties

• Polyiso is stable over a large temperature range (-100°F to +250°F) and can be used as a component in roof systems that use hot asphalt.
• Polyiso has low density, good adhesion to facers, low water absorption and low vapor transmission.
• Polyiso is not affected by oil-based waterproofing compounds, insecticides or fertilizers when properly protected.