Flat Roof Coating Options Explained

What Works Best for Charleston’s Climate?

Flat and low-slope roofs are common across Charleston—especially on porches, additions, commercial buildings, and coastal properties. But unlike steep-slope roofs, they require specialized waterproofing systems, not just shingles.

One of the most effective solutions? Liquid-applied roof coatings.
But not all coatings are created equal.

Let’s break down the most common systems, how they perform, and when to use each.

What Actually Matters in a Roof Coating?

Before comparing brands, you need to understand the 3 key performance metrics:

Types of Flat Roof Coatings (And When to Use Them)

Acrylic Coatings (Water-Based)

Examples: AcryLabs, Progressive Materials, American WeatherStar (acrylic systems)

Performance:

• Tensile Strength: ~250–400 PSI
• Elongation: Moderate
• Permeance: Higher (breathable system)

Best For:

• Budget-conscious projects
• Roofs that need UV reflection + cooling benefits
• Situations where breathability is beneficial

Limitations:

• Not ideal for ponding water
• Can wear faster in heavy rain environments

👉 Charleston Take: Good entry-level option, but not always the best long-term solution for coastal exposure.

Silicone Coatings

Examples: Gaco, GE Enduris, GAF Silicone, United Coatings

Performance:

• Tensile Strength: ~200–500 PSI
• Elongation: High
• Permeance: Very low (excellent waterproofing)

Best For:

• Roofs with ponding water
• Long-term waterproofing
• Coastal and high-moisture environments

Limitations:

• Can attract dirt over time
• Slippery surface
• Not as impact-resistant as urethane

👉 Charleston Take: One of the most popular choices due to its ability to handle standing water and heavy rain.

Urethane (Polyurethane) Coatings

Examples: American WeatherStar Urethane Systems, Tundra, United Coatings

Performance:

• Tensile Strength: ~1,500–2,000+ PSI
• Elongation: Moderate to high
• Permeance: Low

Best For:

• High-traffic roofs
• Areas prone to impact or mechanical damage
• Commercial buildings or rooftop equipment zones

Limitations:

• Higher cost
• Requires skilled installation

👉 Charleston Take: Best for durability and strength—especially where foot traffic or wear is a concern.

Hybrid / Advanced Systems (High-Performance)

Examples: AcryLabs (multi-layer reinforced systems), Polyglass, GAF HydroStop

Performance:

• Tensile Strength: ~1,000–1,500+ PSI
• Elongation: High
• Permeance: Engineered balance (breathable + waterproof)

Best For:

• Full system restorations
• Roofs needing reinforcement (not just coating)
• Long-term performance with warranty backing

👉 Charleston Take: Ideal when you want a true system—not just a coating. Great for extending roof life without full replacement.

Brand Comparison (What You’ll See in the Market)

Some of the most common manufacturers include:

• AcryLabs
• American WeatherStar
• Tundra
• Gaco
• United Coatings
• GE Enduris
• Polyglass
• Progressive Materials
• GAF

Each offers variations of acrylic, silicone, or urethane systems—but the real difference is in how they’re installed, not just the product itself.

When Should You Use a Roof Coating?

A coating system is a great option when:

• The roof is structurally sound
• You’re trying to extend life vs replace
• You want a more cost-effective solution
• You need improved waterproofing and reflectivity

When a Coating is NOT the Right Solution

• Rotted or failing decking
• Severe structural issues
• Improper slope causing major drainage problems
• Multiple failed layers already in place

👉 In these cases, a full replacement or rebuild may be required.

The Charleston Reality: Why Product Choice Matters

In the Lowcountry, your roof deals with:

• Intense UV exposure
• High humidity
• Wind-driven rain
• Occasional ponding water
• Occasional Hail Damage

That’s why choosing the right system—and installing it correctly—makes all the difference.

System Selection Decision Guide

If the roof has ponding water → Recommend Silicone System

If the roof has high foot traffic or mechanical wear → Recommend Urethane System

If the roof is aging but structurally sound → Recommend Hybrid Reinforced System

If budget is the primary concern → Recommend Acrylic System (short-term solution)

Charleston-Specific Considerations

– High humidity requires coatings with proper permeability or moisture control

– Frequent storms and wind-driven rain demand strong waterproofing systems

– UV exposure accelerates breakdown of lower-grade coatings

– Ponding water is common due to low-slope construction and settling

Hail Resistance Breakdown (THIS is where most people get it wrong)

Acrylic Systems (Lanco, Progressive, AcryLabs entry-level)

• Hail Resistance: ❌ Low
• Lower tensile strength means it can tear or puncture more easily
• Better suited for cosmetic protection vs impact protection

👉 Use when: Hail risk is low and budget is the priority

 Silicone Systems (Gaco, GE, GAF, United)

• Hail Resistance: ⚠️ Moderate
• Flexible enough to absorb impact without cracking
• But softer material = can dent or scar under larger hail

👉 Silicone is excellent for waterproofing, but not built for abuse
👉 Still widely used because it handles ponding water extremely well

👉 Use when:

• Ponding water exists
• Waterproofing is priority over impact resistance

Urethane Systems (American WeatherStar, Tundra, United)

• Hail Resistance: ✅ High (Best in class)
• Extremely high tensile strength (up to ~2000 PSI)
• Designed for impact, abrasion, and mechanical abuse

👉 This is the system used when:

• You have rooftop equipment
• You expect hail, debris, or heavy wear
• Commercial durability matters

👉 Polyurethane coatings are specifically known for impact and abrasion resistance

Hybrid Reinforced Systems (AcryLabs, Polyglass, GAF HydroStop)

• Hail Resistance: ✅ Very High (System dependent)
• Uses fabric reinforcement + multi-layer build-up
• Distributes impact across the system instead of a single membrane

👉 Think of this as:

• Not just a coating
• A liquid-applied roofing system

👉 Use when:

• Roof needs reinforcement
• You want coating + structural performance
• Long-term warranties matter

Real-World Takeaways (What Actually Matters)

If your biggest concern is…

• Standing water → Silicone wins
• Hail / durability → Urethane wins
• Budget → Acrylic
• Long-term system performance → Hybrid reinforced

The Biggest Mistake Homeowners Make

They choose a coating based on:

• Price
• Or brand name

Instead of:

• Roof condition
• Drainage
• Exposure (sun, hail, foot traffic)

👉 The wrong coating will fail—even if it’s a “good product”

We don’t just sell coatings—we match the system to how your roof actually performs.

Our Approach at New Beginnings Construction

We don’t just “coat roofs.” We evaluate:

• Drainage patterns
• Existing system condition
• Moisture presence
• Long-term performance goals

Then recommend the system that actually fits your roof—not just what’s easiest to install.

Bottom Line

• Acrylic = Budget + breathable (shorter lifespan)
• Silicone = Best for waterproofing & ponding water
• Urethane = Maximum strength & durability
• Hybrid systems = Best long-term performance when done right

Restore, Protect & Extend the Life of Your Metal Roof With NBC 

Whether you’re in Charleston, Summerville, Moncks Corner, Santee, Ladson, or along the coast, NBC delivers coating systems designed to extend the life of your metal roof and protect your investment. 

Schedule your free inspection today. 
Let NBC help you restore your metal roof — the right way. 

Questions? Give us a call…

843-789-4604