When it comes to flat and low-slope roofs in Arizona, few solutions provide the same long-term protection as a silicone roof coating. As property owners confront the dual threats of relentless sunshine and unexpected monsoon downpours, it’s essential to choose a roofing system that resists the elements—especially the persistent ponding water that spells quick disaster for less-rugged coatings.
Silicone roof coatings stand apart thanks to their exceptional waterproofing ability, unmatched UV resistance, and unique inorganic chemistry. But what does that actually mean for your building, your operating costs, and your peace of mind? Let’s take a closer look.
What Is a Silicone Roof Coating?
A silicone roof coating is a single or multi-part liquid membrane applied directly to an existing roof surface—whether it’s Spray Polyurethane Foam (SPF), metal, built-up (BUR), or a single-ply system like TPO or EPDM. After application, the material cures into a seamless, rubbery layer that acts as a formidable waterproof shield.
How Does Silicone Differ from Other Roof Coatings?
The real magic comes from the chemistry: silicone is an inorganic compound constructed from repeating units of silicon and oxygen atoms, rather than carbon-based organics. This fundamental difference makes silicone coatings practically immune to many of the environmental factors that quickly destroy traditional acrylic, asphalt, or urethane-based alternatives.
Key Benefits of Silicone:
- True Waterproofing: The cured membrane creates a seamless, monolithic barrier—no seams or joints to fail.
- Stands Up to Ponding Water: Unlike most coatings, silicone maintains its integrity even under long-term standing water. It simply doesn’t absorb or break down.
- Extreme UV Resistance: Silicone doesn’t chalk, degrade, or become brittle under intense desert sunlight.
- Temperature Flexibility: Remains elastic in both the summer’s extreme heat and rare winter cold snaps.
- Adhesion: Binds tightly to many substrates, renewing and protecting a variety of aging roofs with minimal tear-off.
Why Ponding Water Destroys Most Roofs (But Not Silicone)
Flat roofs are naturally prone to water collecting after heavy rainfall or even normal irrigation and HVAC runoff. Most coatings—even those labeled “elastomeric”—will degrade, blister, or peel away when exposed to standing water for more than a few days.
Silicone’s superpower is its non-porous, hydrophobic (water-repellent) surface. Rather than absorbing water or softening, silicone simply shrugs it off. Third-party studies and real-world field trials show that silicone roof coatings can stand up to continuous ponding water with no loss of waterproofing, for years at a time.
Real-World Example
A Phoenix commercial warehouse with minimal slope and historic ponding issues received a two-pass silicone coating over their aged foam roof. Despite 50+ days of retention after monsoon storms, yearly inspections showed no deterioration, splitting, or bubbling on the silicone surface—even as acrylic-coated neighboring roofs needed major repair.
Silicone Performance: What Makes It Superior?
Let’s look at some features that make silicone the standout for Arizona’s flat roofs:
- Inorganic Chemistry: Impervious to sun, temperature swings, ozone, and water—doesn’t break down like organic-based coatings.
- High Solids Content: Most quality silicone coatings are 90%+ solids, ensuring a thick, robust film after curing.
- Seamless Protection: Easily bridges gaps, roof penetrations, flashings, and cracks for total waterproof coverage.
- Reflective Options: Bright white and reflective silicones bounce UV rays away, reducing passive solar heating and lowering cooling bills (Energy Star rated products can reflect up to 90% of sunlight).
- Minimal Maintenance: Periodic cleaning and recoating can extend the life of the system by decades—often with no expensive tear-off required.
- Environmentally Friendly: Low VOC products available, and usual application doesn’t burden landfills like full roof replacements.
Silicone Roof Coating vs. Other Coatings
Feature
Silicone Coating
Acrylic Coating
Asphalt/Urethane
Ponding Water Resistance
Excellent – warranted
Weak – not warranted
Poor – prone to blisters
UV Resistance
Superior (inorganic)
Good, degrades over time
Poor, chalks/cracks
Seamless Waterproofing
Yes
Yes, but less durable
Yes, but less flexible
Reflectivity (White Version)
Up to 90%
70–80%
30–50%
Recoat & Maintenance
Easy, cost-effective
Moderate
Tedious, frequent repairs
Lifespan
15–25 years (renewable)
7–12 years
5–10 years
VOC Content
Low/Ultra Low available
Low
High
Compatible Substrates
Most types (SPF, metal, etc)
Most, with prep
Limited
Application Process Overview
- Roof Cleaning & Prep: All debris and dust are removed; repairs made to surface as necessary.
- Primer (if needed): Used on certain substrates for enhanced adhesion.
- Base Coat: Applied by roller or spray; fills cracks and levels minor irregularities.
- Top Coat: After base cures, high-solids silicone is spread to final specified thickness—often 20–40 mils.
- Inspection: Thickness and coverage verified for warranty.
Ideal Substrates for Silicone Coatings
- Spray Polyurethane Foam (SPF)
- Modified Bitumen (Mod Bit)
- Built-Up Roofing (BUR)
- Single-Ply (EPDM, TPO, PVC)
- Metal Roofing
Note: A professional assessment is needed to ensure your specific roof can support a silicone restoration.
Maintenance and Longevity
Silicone-coated roofs require little upkeep. Routine inspection (at least twice per year and after severe storms) ensures drains remain clear and potential damage is caught early. When recoat time arrives—usually after 15–20 years—simply clean, prep, and reapply. The process is fast and low-impact compared to tearing off and replacing an entire roofing system.
Limitations and Considerations
While silicone is unmatched for waterproofing and ponding resistance, it does have some quirks:
- Can be slippery when wet (safety consideration for roof workers)
- Repairs may require special primers if applying other coatings later
- Attracts dust in some climates, which can slightly reduce reflectivity if not regularly cleaned
The Bottom Line: Why Choose Silicone for Flat Roofs in Arizona?
- Ultimate waterproofing against both rain and standing water
- Extreme longevity and minimal maintenance, even under constant sun
- Cutting-edge inorganic chemistry for superior environmental protection
- Energy savings and sustainability, all in a single application
When your building’s integrity and bottom line depend on a roof that simply will not fail—even with days or weeks of ponded water—silicone coatings are the gold standard.
Considering a roof restoration or facing leaks and ponding? Contact East Valley Foam & Coating for a free professional assessment. Discover how a silicone roof coating can deliver lasting, energy-efficient waterproofing, backed by industry-leading warranties.
Title Tag
Silicone Roof Coating: Ultimate Waterproofing, Ponding Water Solution for Flat Roofs
Meta Description
Learn how silicone roof coatings deliver unmatched waterproofing, withstand ponding water, and provide lasting protection for Arizona flat roofs with minimal upkeep.