Polyiso is a closed-cell, rigid foam board insulation consisting of a foam core sandwiched between two facers. The facers are composed of various organic and inorganic materials, usually paper and fiberglass. It is widely used in residential and commercial markets for both roof and side wall applications.
Polyiso insulation has many attributes. Polyiso provides:
Polyiso has the highest per inch R-value of any insulation available. Because of its superior R-value, buildings that use Polyiso have lower heating and cooling costs than buildings insulated with other materials of the same thickness.
Based on consensus standards in both the United States and Canada, Long Term Thermal Resistance (LTTR) is a scientifically supported method to calculate the 15-year, time-weighted average R-value of roof insulation. All Polyiso manufacturers of 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 QualityMarkcm Program. Click here to view the LTTR Fact Sheet.
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.
Polyiso insulation is an ideal choice for green building design, offering:
*Information courtesy of BOMA International
Leadership in Energy & Environmental Design (LEED) Green Building Rating System® was developed by the US. Green Building Council (USGBC) in the early 1990s to measure the environmental impact of constructing a building. USGBC brought all sectors of the building industry together to develop a voluntary, national benchmark for "high-performing, sustainable buildings." PIMA supports this approach, and was one of the first trade associations to join USGBC when that organization opened its doors to industry groups.
The LEED Rating System establishes basic requirements for the various aspects of sustainable design:
Credits or points are earned for meeting the requirements of the specific LEED rating category. A threshold of 40 percent of the available points is required to achieve the minimum LEED Certified rating. Higher performance levels are designated as Silver, Gold or Platinum and are achieved by meeting minimum points for each level.
For suggested opportunities to use Polyiso insulation in a LEED building design, see the Credit Advisory for LEED Projects and Polyiso Roof Insulation.
Using Polyiso insulation may help achieve credits under the LEED rating system. Here are some suggested opportunities to incorporate Polyiso in a building design using LEED for new construction and major renovations (Version 3):
Polyiso insulation offers the most extensive range of code approvals for insulation use in roof systems. It remains the only foam plastic insulation product for direct application to steel deck to earn FM Approval for Class 1 Roof Systems.
A Class 1 roof is often confused with a Class A roof. Class 1 roofs consider several attributes of the roofing assembly, such as under deck fire spread, resistance to external fire exposure, wind uplift resistance and hail resistance. Conversely, Class A roofs consider only resistance to external fire exposure of the roof assembly. Not all Class A roofs meet Class 1, so they should not be treated as equals. The distinction between these types of roof classifications becomes even more critical when the roof system contains foam plastic insulation, such as Polyiso, polystyrene or polyurethane.
Foil faced Polyiso insulation is suitable for use in masonry and rain screen cavity walls. Both commercial and residential buildings typically require a "cavity wall" of air space and insulation between the brick veneer or rain screen and the interior to provide protection from weather and fire. Since the required thickness of insulation affects the cost of construction, an increasing number of builders and architects are choosing Polyiso cavity wall insulation due to its superior R-value to thickness ratio.
When properly specified and installed, Polyiso sheathing insulation can be one of the best values available for residential construction. Its benefits include:
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. Its benefits include:
Polyiso is often used in metal roofing systems. Metal roofing manufacturers incorporate metal clips with distribution plates for application of the metal roof directly over the Polyiso.
In addition, composite products that include Polyiso insulation and an OSB surface are also used. The metal roof manufacturers should be consulted for fastening requirements and other installation requirements.
The moisture content in a Polyiso board with glass fiber reinforced felt as manufactured is approximately 5 percent. Please note that the moisture content at the job or manufacturing site will vary according to ambient conditions and the type of facer used.
Multi-layering of Polyiso roof insulation installed with staggered joints offers a number of advantages, including:
For more information, click the link below for the PIMA Technical Bulletin 113 "Multi-Layering of Polyiso Roof Insulation."
If the overnight weather forecast calls for clear skies, is it necessary to protect Polyiso insulation with a waterproof covering?
Yes, it is still necessary to cover the insulation. The glass fiber reinforced felt used as the facer for most polyiso roof insulation should never be allowed to get wet whether from overnight rainfall or dew. The felt facer can and will absorb water, and it is never a good idea to trap it within the roof system. For more information, click the link below for
PIMA Technical Bulletin 109"Storage and Handling Recommendations for Polyiso Roof Insulation"
Most Polyiso wall insulation products are extremely water resistant. In fact, many are used as Water-Resistant Barriers (WRB) providing the drainage plain behind the veneer throughout the life of the building. WRBs are often left exposed to the elements while the rest of the wall assembly is constructed. For specific instructions and recommendations on how to properly complete the WRB and/or prepare the Polyiso wall insulation during this time, refer to the specific manufacturer.
Many solvents contained in typical construction adhesives have no appreciable effect on Polyiso foam when applied in accordance with manufacturer recommendations. Softening and degradation of the foam can occur when the adhesives are not applied according to the manufacturer's recommendations.
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