Sealants Study
Silicone Sealants Stand the Test of Time
by Errol Bull, Technical Services Manager, Momentive Performance Materials
What do you look for when it comes to roofing systems, materials, and products? One of the key priorities has to be long-term performance. For that, building materials must resist everything the environment has to offer: UV radiation, humidity, extreme temperatures, and years of wear. Roof coatings, in particular, need to provide reliable protection for the substrate over decades.
However, when it comes to comparing acrylics, polyurethanes, and silicones, three of the most common roof coating chemistries, there has been limited empirical data comparing their real-world durability and performance over extended periods.
In 1983, Momentive Performance Materials launched one of the most extensive and longest-running material exposure studies in the industry. Over the course of 40 years, sealant samples based on the same core chemistries used in roof coatings were continuously tested under the extreme climate conditions of Southern Florida.
The results, as you’ll see below, were clear. Silicone rubber sealants consistently outperformed polyurethane and acrylic alternatives in every critical category: weather resistance, adhesion, flexibility, surface integrity, and elastic recovery.
Although this study focused on sealants, insights on the performance of the chemistry itself have wider-reaching implications for the roof coating sector. Silicone-based construction sealants and coatings may not only offer protection, but also deliver lower life cycle costs and longer service lives than their counterparts.
Landmark 40-Year Study
The long-term outdoor weathering study was conducted at the Atlas Weathering Test Site in Florida. This location was selected due to its demanding climate, which includes high humidity, UV exposure, salt air, and temperature changes, conditions that support robust testing of building materials.
Test panels made from painted aluminum and glass were sealed with thirteen commercial-grade sealants from six different producers and mounted at a 45-degree angle facing south. Their performance was evaluated every ten years across six key criteria: adhesion, cohesion, flexibility, elastic recovery, surface appearance, and change in hardness.
The most recent analysis, completed in 2024, marks the 40-year milestone. The results reinforce what many in the construction and roofing industry have seen anecdotally for years: silicone delivers longevity in real-world conditions.
Silicone Outlasts Polyurethane & Acrylic
Silicone rubber sealants outperformed polyurethane and acrylic across nearly every category. Even after four decades of exposure, silicone remained flexible, adhered effectively to substrates, and resisted cracking and surface degradation.
In contrast, polyurethane samples displayed significant hardening, reduced flexibility, and signs of cracking. Acrylics showed early degradation, poor elastic recovery, and notable surface deterioration.
Why This Matters for Roof Coatings
While this was a sealant case study, the parallels with roof coatings are meaningful. Silicone-based roof coatings are based on the same chemistries and face the same environmental performance demands as the tested sealants. The 40-Year Test discovered that silicone chemistries offered the following advantages: weather resistance, flexibility, elasticity, long-term adhesion to a range of substrates, reduced maintenance, and lower life cycle costs
Real-World Performance
The durability observed in this long-term test echoes the results seen in the field. Enduris™ Roof Coating, a 100% silicone, one-coat, high-solids solution, has protected commercial and industrial buildings for decades in some of the toughest climates.
Our internal case studies, coupled with this 40-year weathering benchmark, give us the confidence to back Enduris roof coating with product warranties of up to 20 years. For specifiers and facility managers seeking reliable, low-maintenance roof protection, the study demonstrates that silicone products withstand the test of time.
Conclusion: Proven by Time
The Momentive comparative study offers clear evidence: silicone rubber significantly outlasts polyurethane and acrylic materials in demanding environmental conditions. Its resistance to UV degradation, humidity, and mechanical stress helps deliver performance that stands out among alternatives. For roofing professionals, the message is clear. When it comes to long-term protection, flexibility, and durability, three critical attributes, silicone is the chemistry of choice. This landmark test provides evidence that silicone roof coatings are unmatched in terms of long-term performance.
