Elastomeric vs. Silicone: The Commercial Property Manager’s Guide to Roof Coatings
———————————————————————————— Nast Roofing Co. ————————————————————————————
As a commercial property manager in South Florida, keeping your operating expenses predictable while maintaining a watertight building is an ongoing balancing act. Between the baking sun, heavy tropical downpours, and relentless coastal humidity, our roofs take a constant beating.
When an aging low-slope or flat commercial roof begins showing its age, many building owners assume their only option is a costly, disruptive tear-off and replacement. In reality, fluid-applied roof restoration coatings offer a code-compliant, budget-friendly alternative that can add 10 to 20 years of life to your existing roof, at a fraction of the cost of a full replacement.
The two most common choices for commercial restoration are
elastomeric acrylic coatings and
high-solids silicone coatings. While both fall under the broad category of elastomeric (flexible) coatings, their chemical makeup behaves very differently in the real world.
Nast Roofing is your trusted
commercial roofing company in Fort Lauderdale, we’ve spent more than 30 years evaluating and restoring commercial roofs across South Florida. Here is an honest, contractor-level breakdown to help you choose the right coating chemistry for your commercial asset.
What Is a Fluid-Applied Roof Coating?
A roof coating is not just a coat of white paint. It is an engineered, monolithic (seamless) liquid membrane applied over an existing, structurally sound roof substrate—such as modified bitumen, single-ply TPO/EPDM, metal, or built-up roofing (BUR).
Once cured, the coating forms an elastic, seamless barrier across the entire roof surface, sealing penetrations, flashings, and seams where leaks typically originate.
According to guidelines from the
Cool Roof Rating Council (CRRC), high-reflectivity roof coatings can reflect upwards of 70% to 85% of solar radiation away from a building, dramatically reducing rooftop surface temperatures and cutting cooling loads on your top-floor HVAC systems.
1. Elastomeric Acrylic Coatings: High Reflectivity, Budget-Friendly
Elastomeric acrylic coatings are water-based polymers that cure into an elastic, flexible membrane. They have been an industry standard for decades, particularly on sloped commercial roofs and metal building systems.
The Advantages of Acrylic Coatings
- Cost-Effective Entry Point: Acrylics generally cost less per gallon than silicone, making them an attractive choice for large square-footage facilities with tight capital expense budgets.
- Exceptional Dirt Pickup Resistance: Acrylic coatings dry to a firm, non-tacky finish. Unlike silicone, which naturally attracts airborne soot, dirt, and dust, acrylic retains its bright white reflectivity over an extended period.
- Easy Recoatability: Because acrylic is water-based, applying a maintenance coat 10 years down the road is straightforward and requires minimal specialized primers.
The Disadvantages in South Florida
- Vulnerability to Ponding Water: Because acrylics are water-based, prolonged exposure to standing (ponding) water will cause the cured coating to soften, bubble, and re-emulsify. If your flat roof has low spots where water sits longer than 48 hours, acrylic will fail prematurely.
- Weather-Sensitive Installation: Acrylic requires dry, warm weather and several hours of cure time before rainfall. A sudden South Florida afternoon thunderstorm can wash away uncured acrylic coating before it sets.
2. Silicone Roof Coatings: The Ultimate Waterproofing Defense
High-solids silicone coatings are moisture-cure, inorganic materials that form a durable, rubber-like membrane. In commercial flat roofing, silicone has quickly become the preferred restoration option throughout coastal and tropical climates.
The Advantages of Silicone Coatings
- Impervious to Ponding Water: Unlike acrylic, silicone is naturally hydrophobic and completely inert to water submersion. Even if sections of your flat roof collect standing water after a downpour, silicone will not soften, degrade, or delaminate.
- Superior UV & Thermal Stability: The chemical bond of silicone (polysiloxane) resists ultraviolet radiation significantly better than organic polymers. It does not become brittle, chalk, or crack under intense South Florida UV exposure.
- Higher Solids by Volume: High-solids silicones (often 90%+ solids) allow for single-coat applications that achieve the required dry film thickness (DFT) quickly, speeding up project turnaround and minimizing tenant disruption.
The Disadvantages
- Higher Upfront Material Cost: Silicone coatings require a higher initial investment than acrylics.
- Attracts Surface Dirt: Silicone has a slightly tacky surface that tends to hold dust, engine exhaust, and organic debris over time. While this does not compromise waterproofing, it can slightly diminish thermal reflectivity unless periodically washed.
- Adhesion Specifics: Nothing sticks to cured silicone except more silicone. If the roof ever needs additional tie-ins or flashings down the road, silicone-compatible materials must be used.
Side-by-Side Comparison: Elastomeric Acrylic vs. Silicone
| Feature | Elastomeric Acrylic | High-Solids Silicone |
|---|---|---|
| Material Base | Water-based acrylic polymer | Moisture-cure polysiloxane |
| Relative Material Cost | $(Budget-friendly) \vert{}$$ (Moderate investment) | |
| Ponding Water Resistance | Poor (Breaks down under standing water) | Superior (Impervious to standing water) |
| UV & Weathering Life | 7–10 Years (Can chalk over time) | 10–20+ Years (Inert to UV radiation) |
| Dirt & Dust Resistance | High (Stays clean longer) | Moderate (Attracts environmental dust) |
| Ideal Substrate / Slope | Sloped metal roofs, positive drainage decks | Flat commercial roofs, low-slope membranes |
When Is a Roof Coating the Right Choice?
Before applying any coating, property managers must verify that the underlying roof structure is a qualified candidate:
- Dry Insulation Deck: Coatings are designed to seal roofs, not trap existing moisture. An infrared thermal moisture survey should be conducted to confirm the underlying insulation board is dry. Any localized wet spots must be cut out and replaced before coating.
- Structural Integrity: The existing membrane must have solid adhesion to the deck, and seams should be structurally sound or repairable with reinforcement fabric.
- One Existing Roof Layer: Under the Florida Building Code, commercial roofs generally cannot carry more than two total roofing systems. Because fluid-applied coatings are categorized as a maintenance restoration rather than a structural re-roof, they typically do not count as a separate layer, often saving thousands on engineering and permit fees.
Restore Your Commercial Roof with Nast Roofing
A smart commercial roof restoration protects your property, keeps tenants happy, and preserves valuable capital reserves.
At
Nast Roofing, we carry Florida State License #CCC057134 and hold GAF CoatingsPro™ certifications for liquid-applied roofing systems. Whether your facility needs a full
commercial roof replacement, repairs, or a comprehensive roof coatings evaluation, our team delivers transparent pricing and dependable, long-term warranties.
Want to find out if your commercial building qualifies for a fluid-applied coating restoration? Contact Nast Roofing today at (954) 475-0610 or visit us to schedule a professional inspection.
Frequently Asked Questions
Will a roof coating stop existing active leaks?
A roof coating will create a seamless, watertight seal over small cracks, hairline fractures, and aging seams. However, active leaks caused by saturated insulation or torn flashings must be properly patched and repaired before coating application. A coating is a restoration system, not a quick patch over structural failure.
Can you coat over an old gravel built-up roof (BUR)?
Yes, but surface preparation is critical. All loose gravel must be vacuumed or spudded away, and an approved leveling asphalt or high-solids primer must be applied before installing the topcoat system.
Can our business write off a roof coating faster than a replacement?
In many cases, yes. Under current IRS guidelines(including Section 179 rules), roof coatings are frequently classified as maintenance and repair expenses rather than capital improvements, allowing commercial property owners to deduct the entire expense in the year it was completed rather than depreciating it over 39 years. Always consult your CPA for specific tax guidance.
Which system is better for South Florida flat roofs?
For flat commercial roofs throughout Broward and Miami-Dade counties, silicone is almost always the superior choice. Because afternoon downpours and low spots are so common, silicone’s ability to resist ponding water ensures your warranty remains valid and your building stays dry.
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Owner & CEO of Nast Roofing
Written by Tim Nast
Tim Nast is the Owner and CEO of Nast Roofing, with more than 35 years of experience in roofing and contracting. A Florida State Certified Roofing Contractor since 1994, Tim specializes in residential and commercial roofing, Florida Building Code requirements, and roofing applications throughout South Florida.
