What Is Extruded Polystyrene Insulation (XEPS)?
There are four major rigid plastic foam insulations commonly used for residential, commercial and industrial insulation: extruded polystyrene (XEPS), expanded polystyrene (EPS), polyurethane (PUR), and polyisocyanurate (PIR). Each type has individual characteristics and specific advantages and disadvantages for particular building applications.
Nonetheless, the stable properties of polystyrene, when combined with a unique foam extrusion process, produce an exceptionally useful product with benefits for nearly all construction and engineering applications.
Extruded polystyrene has a well established reputation for long-term reliability and superior resistance to the elemental forces of nature: time, water, cold, heat, and pressure.
Consider these forces when choosing insulation
This continuous extrusion process results in a unique foam product with a uniform closed-cell structure, a smooth continuous skin, and consistent product qualities, qualities unequaled by other insulation types.
Comparing Insulation Properties
However, each insulating material's R-value may vary depending upon the characteristics of its manufacture and conditions of use. In particular, the responsible design professional should consider the long-term aged R-value of installed insulations, as well as the R-value at the average use temperature, when specifying insulations.
The insulation value of most rigid foam boardstock products relies in part on the blowing agent used during their manufacture. The permeation of air, which is more conductive, into the board after manufacture can affect the R-value of the insulation with time. For accurate comparisons and for reliable performance over the life of a building or insulating product, it is important to use appropriate long-term aged R-value data from all insulation manufacturers.
DiversiFoam Products and XEPS industry organizations continue to recommend that design professionals and specifiers use long-term aged values for comparison and design calculations.
Also, the R-values of various insulation types change with different average use temperatures. However, since different types do not vary linearly or proportionally to other types, R-values at representative use temperatures should be used for accurate comparison. Specifically, some insulations with relatively high R-values at warm temperatures lose insulating power as the temperature drops. Note that CertiFoam extruded polystyrene actually has greater insulating power (higher R-value) as the mean temperature drops.
The universal physical and chemical properties of water can have serious consequences for many building materials. Fortunately, the superior moisture resistance of extruded polystyrene foam insulation is well established. Not only is polystyrene naturally hydrophobic (no chemical affinity for water), but its fine closed-cell structure and smooth continuous skin helps the foam resist moisture better than other types of insulating materials.
Temperature fluctuations, above and below freezing, in the presence of moisture have serious consequences for most building materials. However, the characteristic moisture resistance of extruded polystyrene foam, combined with its tough yet resilient nature, results in excellent resistance to freeze/thaw damage.
Extruded polystyrene foam is easy to handle and available in a variety of sizes and compressive strengths to suit varied application requirements.
These and other characteristics also make extruded polystyrene foam insulation the proven product choice for below grade insulation, protected membrane roof or plaza systems and a number of special insulation applications. The uniquely resistant and durable qualities, inherent to extruded polystyrene foam, make CertiFoam one of the most dependable long-term insulation materials available.