Is the Roof Insulation’s R-Value Guaranteed?
Is it the BEST Value?
Many times Polyisocyanurate (Polyiso) roof insulation is specified because it comes standard in NDL (No Dollar Limit) Roof Warranties. No Dollar Limit Roof Warranties sound good but does it guarantee the R-value of the insulation? Would you be surprised if the answer is no, it doesn’t? This can provide a great “Value Engineering” opportunity for your project. NDL Roof warranties using Polyiso are not free. Some believe they are “overpriced extended warranties” that force you to buy all the components from one source, which in turn, drives up the cost of roofing. So ask your roofer what type of insulation he is using and then ask him to give you an option to use Engineered EPS from Plymouth Foam.
The technological advancement for Engineered EPS is truly amazing and the new research is showing why you should insist on using Engineered EPS Roofing Insulation on your project. The real secret is EPS is the best value in roofing. Not only is it less expensive, it is the best value in roof insulation for many reasons.
• EPS’s R-value stays consistent over the life of the product and we guarantee it!
• In cold weather, Polyiso’s R-value goes down, our Engineered EPS goes up.
• Safer product - no offgassing, no CFC OR HCFC and 100% recycable.
• Closed cell that resists moisture but has the ability to expel it faster.
• Compatible with other rigid insulations for mixed systems.
• Available in 12 various compressive strengths
Want to save money on a project? Ask your specifier to value engineer and use Plymouth Foam EPS. The saving will surprise you.
Need more help convincing the specifier that Plymouth Foam’s Engineered EPS is the best product? Ask us for our substitution package.
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Ever since I saw my first bullt-up roof blister caused by off-gassing of Polyisocyanurate Insulation (1988), I have been analyzing and studying R-values in insulation. My major concern and conclusion was that R-value was not being stated correctly. This made predictive energy modeling and utility cost estimating not very reliable, not to mention over paying for overstated R-values. I believed that full disclosure through a method like LTTR (Long-Term Thermal Performance) would help with give a more accurate accounting. (LTTR - Read Article)
This October 2019, the US Federal Trade Commission will finally close a loophole in regard to Extruded Polystyrene (XPS) and their avoidance to “fully reflect the effect of aging” on their product. “The final rule, though not mandating a prescriptive LTTR method, requires that manufacturers publish R-values” that are more accurate.
The EPS Industry Alliance in a recently published paper, (Polystyrene Foam Insulation in Long-Term Building Applications, Effective R-Values) provided a method to estimate effective R-value for polystyrene insulation. This has started to address my two biggest issues with Effective R-values - 1) “Long-Term” and 2) testing temperature of 75ºF.
Long-term testing statements in insulation should not be 5-15 years (we don’t build building to last 5 years) but rather 50 years. So what is the average R-value over 50 years in a building? Fifty year testing is more reflective of homes and buildings insulation life cycles. Even though the Federal Trade Commission is mandating LTTR for XPS, they are still leaving a loophole by allowing “open” LTTR test methods and not requiring a 50 year prescriptive method. It will be interesting to see what the XPS industry comes up with for R-value. Will it be 4.3r/inch like the testing showed from the EPS Industry Alliance?
The issue of “Testing Temperature” has bothered me for years. Why test at 75ºF? Who needs R-value at 75º? In the Northern States, where heating is a concern, it is more realistic to look at R-value testing temperature at 40º, if not 25º in some states. The opposite is true in the South during summer where 90º may be a more reflective testing temperatures. Knowing the R-value performances of insulation, at various temperatures, is critical for designers to make important R-value decisions. They would have the ability, based on their climate, to select the most appropriate insulation. However, the current testing temperature approach of 75º is really a “one shoe fits all” approach and is not very helpful and leads to poor energy conservation decisions.
It has taken over 30 years to see a more accurate accounting of what the R-values of rigid insulation really is and I applaud the FTC for one more step forward. Just 2 more to go - 50 year LTTR and Variable Temperature Testing Disclosure. Accomplish that and we can finally focus on a really important issue — moisture in insulation and its effects.
John Calkins - JC Edison and Associates
In high school, I remember watching the track team race around the track. One runner Peter, a farm kid, was fascinating to watch as he always grabbed the early lead. Peter always looked so fast but in the end he would typically finish in 3rd or 4th place. In that moment, early in the race, Peter looked like a world class athlete that would easily win gold at the Olympics. In those early moments, that frozen time, the measure of performance was perfect.
Thirty-six years later and I see the same thing happening in the rigid insulation market. Its like watching Polyiso, and XPS insulation running just like Peter, getting off to a tremendous lead regarding R-value, but then fading out at the end. That perfect moment in time is when that R-value gets measured and they look like superheroes but in reality they just “blowhards.” Pardon the pun as the blowing agent escapes and lowers the r-value. (LEARN WHY)
When it comes to below grade or roofing insulation, Polyiso and XPS start out with really good R-value numbers but they don’t last (LEARN MORE). Unfortunately, you pay for these early performance numbers, sometimes as much as 50% more. Paying for performance isn’t bad but not knowing that the product will fade out is a different matter.
The old idiom, “slow and steady wins the race” really holds true in insulation. EPS might start out slow (or lower r-value) but is consistent through its life and ultimately wins the race. Not only does EPS (Expanded Polystyrene) have a steady consistent R-Value but when compared with XPS and Polyiso, it also performs better in the field. XPS and Polyiso, when wet, hold the moisture and loss much of its r-value. EPS has the ability to hold its r-value and even expel moisture under exsiccate conditions.
Next time, when you’re looking to specify or install insulation on a project, remember that Polyiso and XPS look great at the beginning but EPS is the steady performer and the best value in rigid insulation. Your customer deserves the winner - EPS.