Roof-rejuvenation products are often advertised with impressive percentages: better granule adhesion, more flexibility, less weathering, greater tear strength. The numbers can be real laboratory results and still require careful interpretation. A property test on a shingle is not the same thing as a long-term field trial proving a specific number of additional roof years.
Two Different Questions
When evaluating a rejuvenator, separate these questions:
- Does the treatment measurably change the shingle?
- Does that change translate into a predictable number of extra service years on a complete roof?
Laboratory testing is much better at answering the first question than the second.
The Ohio State / Roof Maxx Work
An Ohio State University technical report evaluated a soy-methyl-ester-based Roof Maxx treatment on aged asphalt shingles. Testing included granule adhesion, permeability, flexibility and other characteristics using recognized test methods. The report concluded that treatment produced considerable improvement in tested characteristics and showed potential to extend roof service life.
One especially useful detail is the wording of the conclusion: potential to extend service life. That is scientifically more restrained than promising that every roof receives a guaranteed number of additional years.
The report also discloses its funding context: it was prepared at the request of Roof Maxx Technologies and the Ohio Soybean Council as part of an Ohio Soybean Council-funded project, and it states that discussion of a specific product does not constitute Ohio State endorsement.
The Current Roof Rejuvenate Testing Summary
Roof Rejuvenate currently publishes a summary of 2025 testing conducted by PRI Asphalt Technologies. According to the summary, 15-year-old shingles from a residential roof were subjected to 1,500 hours of accelerated weathering, described as simulating five years of natural aging. Treated and untreated samples were then compared.
| Reported property | Untreated | Treated | Published difference |
|---|---|---|---|
| Granule loss | 1.43 g | 0.67 g | 53% less granule loss |
| Tear strength, machine direction | 7.6 N | 9.4 N | About 24% higher |
| Pliability | 15-C | 5-C | Published as 66.7% improvement in cold-weather pliability |
| Color change | — | 7.02 | Visible darkening/restoration |
Those numbers are evidence that the tested treatment affected the tested shingle samples. The publicly available two-page document is a product testing summary rather than a complete long-form field-performance study, so readers should not convert “53% less granule loss in this test” into “53% longer roof life.” They are different measurements.
What About the Older “86% Granule Adhesion” Claim?
Older rejuvenation marketing frequently cites an 86% granule-adhesion improvement. A 2018 RoofRestor screening evaluation published by that product’s distributor reports granule loss dropping from 1.11 grams untreated to 0.15 grams treated, characterized as an 86% improvement in granule adhesion. That is a different product/test context from the current Roof Rejuvenate summary, which reports 53% less granule loss.
This is why percentages should always be attached to the exact product, formulation, sample and test. “86% better granule adhesion” is not a universal property of all roof rejuvenators.
Accelerated Weathering Is Useful—but It Is a Model
Accelerated weathering lets researchers compare treated and untreated specimens without waiting years for outdoor exposure. That makes it useful for product development and comparative testing. But a roof in service also experiences conditions that a laboratory sample may not reproduce completely: wind uplift, roof geometry, flashing failures, installation defects, hurricanes, repeated wetting, attic conditions, foot traffic, biological growth, debris, repairs and substrate movement.
For Florida homeowners, that distinction is particularly important. A treatment may improve the shingle material while the roof remains vulnerable at penetrations, flashings, valleys, edges or other details.
What Evidence Would Be Even Stronger?
- Multi-year field studies of treated and untreated roofs in the same climate.
- Large sample sizes across different shingle brands, ages and roof exposures.
- Published failure rates and retreatment rates.
- Clear separation of product performance from repairs performed during the roof tune-up.
- Long-term Florida data covering high heat, UV, humidity, wind and tropical-storm exposure.
- Warranty-claim data showing what proportion of treated roofs required retreatment or replacement within the claimed extension period.
Surface Blueprint Rule for Reading Product Claims
When a roof product advertises a percentage, we want four things attached to it: the exact property measured, the test method, the untreated comparison, and the product/formulation that was actually tested.
When a roof product advertises additional years of life, we want something else: evidence that connects the laboratory property improvement to real field service life. Those are related questions, but they are not interchangeable.