How To Improve The Initial Lifespan of SPF Roofs

avatarby Castagra Products, Inc.Last updated Jul 6, 2020Category: Roofing

"Roofs that were previously thought to be too far gone to be rejuvenated, are often contenders for Ecodur coating and repair."


Increasing building efficiency is a top priority for most contractors.


building efficiency

The roofing industry is particularly aware of this trend. Roofs can achieve higher efficiency through reflectance, insulation, or through peak performance (a combination of both).


For reflectance, we look for products with high SRI (solar reflectance index) ratings. This is a combined measurement of solar reflectance and emissivity used to indicate how hot the surface is likely to become during direct sunlight. Products with a high SRI rating increase efficiency by preventing solar heating of the surfaces they protect. However, they do little-to-nothing to keep cool air in a building.


For insulation, we look to R-values. An R-value is a measurement of how well insulation prevents heat transfer. The higher the R-value, the cooler a building is likely to be. Insulation has the added benefit of keeping heat in the building during cool weather. Among the highest R-values available in roofing is SPF or spray polyurethane foam. With an R-value of 6/inch, a 1½” pass of SPF can reduce heat flow by over 90%.


By creating a system that combines both values (peak performance), we can maximize building efficiency. This leads to lower cooling costs, longer service life on HVAC systems, and more comfortable environments.



However, there is one problem with this ideal system.

According to the 2005 Roofing Industry Durability and Cost Survey, coated SPF is among the roofing products with the lowest expected lifespan. With a mean life of only 14 years, and failures reported in as little as 7, it may be easy to dismiss this highly efficient system as a short-term solution.


SPF Roofing



But why is SPF a lower lifespan system?

The foam itself has no UV resistance and relies solely on the topcoat to protect it. Exposed foam can degrade in as little as 5 hours of sunlight. This turns the exposed foam into a powder that easily blows or washes away, exposing the next layer of foam, and creating a rapidly increasing failure.

SPF roof coating


The most common topcoats for an SPF system are acrylic and silicone coatings. Silicone does not degrade in UV or water exposure, but can be difficult to repair. Acrylic coatings are easy to repair but will chalk and degrade by approximately 1 mil/year in most environments. Both are great solutions if left alone (except for routine maintenance). Unfortunately, with a hardness range of only 37 to 60 Shore A, neither prevents physical damage from unpreventable events such as hail, blowing debris, or animal damage. Once the top layer is cracked, the foam beneath is exposed and the clock is ticking.


cracked SPF



What can be done?

With up to double the hardness of silicone and acrylic coatings, Castagra’s Ecodur roof coating is an excellent choice to coat new SPF. It will provide superior waterproofing, outmatched impact resistance, and can be topcoated to provide a high SRI rating.


spf roof coating



What about existing SPF roofs?

The good news is that there are steps that can be taken to increase the lifespan of an SPF roof. For existing SPF roofs, the absolute best thing is routine inspections and maintenance. With annual inspections and maintenance, you can extend the life of your SPF roof indefinitely. When it is time to re-coat, consider a stronger, longer-lasting material such as Ecodur.

spf roof coating



What if it’s already too late?

It may not be. With no maximum thickness, Ecodur can fill even the biggest foam loss and blisters. Roofs that were previously thought to be too far gone to be rejuvenated, are often contenders for Ecodur coating and repair. In many instances, they will even qualify for a 20-year labor and materials warranty.

blister coating




If you have questions on an SPF, or any other roof coatings project, please contact Castagra at 1-888-388-2935 or 



Written by: Jef McCurdy

Technical Director - Castagra 

Castagra Products, Inc. Castagra Products, Inc.

Castagra Products, Inc.

Repair Almost Any Commercial Flat Roof, Today! Call Us Toll Free at 1-888-388-2935.

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