Silicone Roof Coating Systems: The Complete Guide
Silicone roof coatings are high-solids, moisture-cure membranes built for flat and ponding-prone commercial roofs.
Drag to reveal the restoration.
BeforeAfterSilicone roof restoration — a weathered flat roof sealed with a seamless, ponding-proof silicone membrane.
Silicone quick specs.
Every spec below is covered in depth further down the page.
What Is a Silicone Roof Coating?
A silicone roof coating is a high-solids, moisture-cure membrane applied as a liquid over your existing roof.
Like most other roof coatings it cures into one seamless rubber layer that reflects UV, heat while sealing every seam and fastener. The big advantage is that it keeps performing even under standing water.
Where silicone works best.
Flat & Low-Slope Single-Ply Coming soonThe silicone sweet spot — aged TPO and EPDM sealed seamless without a tear-off.
Ponding-Prone Roofs Coming soonThe defining application: silicone is the one chemistry rated to live under standing water.
Modified Bitumen & BUR Coming soonA reflective, waterproof cap over sound granulated asphalt systems.
Metal & Spray Foam Coming soonSeals seams and fasteners on metal; the premium UV shield over SPF.Why owners and contractors pick silicone.
🏢 Why owners choose silicone
- Ponding-proof — performs under standing water
- Cool-roof reflective — cuts rooftop heat
- No tear-off, no downtime — the building stays open
- 10–20+ year cycles with simple silicone recoats
- Seamless waterproofing over every seam and fastener
🛠 Why contractors choose silicone
- High solids — often a one-coat system, fewer passes
- Moisture-cure shrugs off dew and pop-up showers
- Wide application window — 35°F and up
- Bonds to TPO, EPDM, mod-bit, metal and SPF with the right primer
- Fast turnaround — more roofs per season
The typical silicone coating system.
Varies by manufacturer
How to qualify a roof for silicone.
In Silicones case ponding water water doesn’t disqualify the roof — it’s often the reason silicone gets the job.
What still matters is everything underneath:
✅ Good candidate
- Structurally sound deck
- Dry insulation and substrate
- Stable existing membrane or coating
- Ponding areas — silicone handles them
- Substrate that passes an adhesion test
- Owner committed to the silicone recoat path
❌ Poor candidate
- Saturated insulation
- Severe structural corrosion
- Failed adhesion over large areas
- Heavy daily foot traffic without walk pads
- Surfaces that can’t be properly cleaned and prepared
- When looks matter. Silicone gathers dirt faster than any other coating.
Limitations — what can go wrong.
⚠ Dirt pickup & gloss lossCause: Glossy surface attracts airborne grimePrevention: Plan periodic washing into the maintenance budget
⚠ Adhesion loss & peelingCause: Coating over chalk, contamination or unprimed slick substratePrevention: Adhesion-test every substrate; prime where the test says
⚠ Trapped MoistureCause: Applying silicone over wet substrate.Prevention: Make sure surface area is completely dry before applying silicone.
⚠ Thin applicationCause: Not enough finished membrane thicknessPrevention: Verify wet mils every pass with a gaugeWeather windows for a silicone job.
Silicones cure by reacting with moisture in the air — humidity helps rather than hurts, which is why they forgive weather that ruins water-based coatings.
Silicone specifications & coverage.
There is no universal silicone spec — dry film thickness, coverage and coat count are set by each manufacturer’s system and the warranty you want.
Silicone’s edge is solids content: at 90%+ solids, nearly everything you apply becomes dry film, so systems often finish in fewer coats than acrylic.
How much silicone would your roof need?
Our material calculator will tell you exactly how much material your roof needs.
Cost, service life & warranties.
Typical installed cost
Roughly $3.00–$6.00 per square foot installed — usually 30%-50% the cost of replacement, and about $0.50–$1.50 above a comparable acrylic system.
On ponding roofs that extra cost can save thousands in repairs down the line.
Service life & recoats
Expect 10–20+ years per cycle depending on the thickness. Renewal is silicone-over-silicone: clean and recoat at a fraction of the original cost — remembering that silicone is a one-chemistry commitment.
Warranties & the tax angle
Warranty terms follow the manufacturer’s system specs.
And because a coating is generally maintenance rather than a capital improvement, many businesses deduct the full cost in year one under Section 179.
Silicone products compared side by side.
See all 31 products compared side by side ▾
| Product | Solids | Published coverage | Warranties | Spec |
|---|---|---|---|---|
| Silicone 410American WeatherStar | 69% +/- 2% by volume (ASTM D2697) | — | Used in StarGard-warranted systems (10/15/20-year system terms; coverage set per warranty term) | TDS |
| High-Solids Silicone 412American WeatherStar | 92% +/- 2% by volume (ASTM D2697) | — | Top coat of Ure-A-Sil 20-year StarGard hybrid system; also used in Met-A-Sil and Foam-Gard systems | TDS |
| APOC 585 Armor Flex Liquid Silicone Roof MembraneAPOC | 98% by volume | 1.5-4 gal/100 sq ft depending on substrate roughness and warranty term | 1-year base product warranty; extended terms with registration at apoc.com within 60 days | TDS |
| Silkoxy H3Everest Systems | 90% by volume | Max 1.5 gal/100 sq ft per coat; yield 14 dry mils per 1 gal/100 sq ft | Everest system warranties up to 20 years via Certified Applicators (ponding water excluded) | TDS |
| Silkoxy H3-EZEverest Systems | — | Roller-optimized low-viscosity version of Silkoxy H3; apply per system spec | Everest system warranties up to 20 years via Certified Applicators | TDS |
| Silkoxy Flashing GradeEverest Systems | — | Detail/flashing grade for seams, penetrations and repairs | Covered under Everest silicone system warranties on eligible projects | TDS |
| GacoFlex S20 Series 100% SiliconeGaco | 95% by volume | 1.5 gal/sq per coat smooth; 2 gal/sq granulated (to ~22 dry mils) | Full-system labor+material via licensed applicators; 50-yr limited material | TDS |
| Unisil Silicone Roof CoatingGAF | 71% by volume | Max 1.5 gal/sq per coat, min 2 coats; warranty totals 2.0 (10-yr), 2.75 (15-yr), 3.5 (20-yr) gal/sq | 10 / 15 / 20-year liquid-applied limited warranty by application rate | TDS |
| High Solids Silicone Roof CoatingGAF | 96.6% by volume | Up to 2.75 gal/sq in one pass (substrate permitting) | GAF liquid-applied limited warranties; marketed with 20-yr terms | TDS |
| GE Enduris 3500GE Performance Coatings | 90% by volume | Theoretical 2.5 gal/100 sq ft in one or more coats for 20-year spec; typically one-coat application | Up to 20-year labor & material warranty via MPM Authorized Applicator Program; pre-job and final inspections required | TDS |
| GE Enduris 3500 E+GE Performance Coatings | — | One-coat high-solids application; rate per project spec and warranty term | Up to 20-year labor & material warranty available through Authorized Applicator Program | TDS |
| GE Enduris 3525GE Performance Coatings | 90% by volume | One-coat, high-solids application; rate varies by warranty term (approx 2-2.5 gal/100 sq ft for extended warranties) | 20-year labor & material warranty available; NSF P151 Certificate of Compliance (potable water rainwater harvesting) | TDS |
| GE Enduris Liquid FlashingGE Performance Coatings | — | Detail/repair flashing applied by trowel, stiff brush or gloved hand; no primer required | Covered under GE Enduris roof coating system warranty on eligible projects | TDS |
| 887 Tropi-Cool 100% SiliconeHenry Company | 91% by volume | 1.5 gal/sq minimum, one-coat | Lifetime limited warranty | TDS |
| Pro-Grade 988 SiliconeHenry Company | 92% by volume | Min 1.5 gal/sq; 50+ mils possible in one coat | Henry Material Plus and Gold Seal system warranties | TDS |
| 670HS Karna-Sil Ultra Silicone CoatingKarnak | 91% by volume | Single coat 1.5 gal/100 sq ft (24 wet mils); up to 3 gal/sq on approved horizontal substrates; over 180 epoxy primer or 400-series base coat as specified | Karnak system warranties via approved applicators; retail limited warranty | TDS |
| 100% Silicone Roof CoatingMule-Hide Products | 90% by volume | Min 1.5 gal/100 sq ft; total rate varies by warranty term | Up to 20-year Mule-Hide system warranties on multiple substrates; installed by Warranty Eligible Contractors | TDS |
| PolyBrite 90.1Polyglass | 92% +/- 3% solids by volume (ASTM D2369) | PolyBrite 90 published rate: 1.25 gal per 100 sq ft per coat at 20 wet mils, typically two coats; 90.1 can be applied in excess of 40 wet mils in a single coat without blistering | 12-month standard product warranty; eligible for Polyglass system warranties (terms via Polyglass warranty program) | TDS |
| PolyBrite 95.1Polyglass | — | — | 12-month standard product warranty; eligible for Polyglass system warranty programs | TDS |
| HS 3200 Series High Solids Silicone Roof Coating (HS 3201 White / 3202 Tan / 3203 Light Gray / 3204 Dark Gray)Progressive Materials | 92% +/- 3% by weight (ASTM D2369) | Specified by dry-mil warranty tier rather than flat gal/100 sq ft; can be applied in excess of 40 wet mils in a single coat without blistering | Full System Limited Warranties, 5 to 20 years | TDS |
| HS 3200-HB Roller-Grade (High Build) Silicone Roof CoatingProgressive Materials | Over 95% solids (as published on product page) | Roller-applied; can be applied in excess of 70 wet mils in a single coat | Eligible for PM Full System Limited Warranties (5-20 years) | TDS |
| Pro-Shield Fully-Reinforced Silicone CoatingProgressive Materials | — | — | — | TDS |
| Silicone44 Rubberized Silicone (44-300)Sherwin-Williams Uniflex | 98% by volume | ~1.33 gal/sq min; commonly 2 coats at 1 gal/sq; UNIGUARD 2 gal/sq (15-yr), 2.5 gal/sq (20-yr) | UNIGUARD 10 / 15 / 20-year system warranties | TDS |
| Sikalastic-500Sika | 92-96% by volume and by mass (ASTM D2697) | RoofCoat 10: 1.5 gal/100 sq ft; RoofCoat 15: 2.0 gal/100 sq ft; RoofCoat 20: 2.5 gal/100 sq ft | Sika RoofCoat 10/15/20-year coating system tiers | TDS |
| Silicone High Build CoatingTopps Products | 90% by volume | High-build single/two-coat application per Topps spec; resists ponding water | 15-20 year expected service life with maintenance | TDS |
| AlphaGuard Si 100Tremco Roofing | 69% by volume | Smooth BUR/MB/single-ply: base 1 gal/sq (16 wet mils) + top 1.5 gal/sq (24 wet mils); granulated MB/SPUF: base 2 gal/sq + top 1.5 gal/sq | Eligible for Tremco system warranties; TremCare maintenance programs | TDS |
| #924 Eterna-Sil Premium Silicone Roof CoatingTropical Roofing Products | 97% by volume | Min 1.5 gal/100 sq ft single pass; max 2.5 gal/100 sq ft per pass | Eligible for TRP/SOPREMA limited product and full-system labor & material warranties via warranty application | TDS |
| #923 Eterna-Sil Roof CoatingTropical Roofing Products | — | Direct-bond single-pass silicone; rate per system specification | Eligible for TRP/SOPREMA limited product and full-system warranties | TDS |
| #9400 Eterna-Sil Premium MasticTropical Roofing Products | — | Seam sealer and repair mastic for seams, penetrations and fasteners; trowel or gloved-hand application | System component covered under TRP/SOPREMA coating system warranties | TDS |
| KNIGHTSHIELD KS-5100 High Solids Silicone Roof CoatingW.R. Meadows | 94% by volume | 1.5 gal/100 sq ft (24 wet mils); target 25 wet / min 22 dry mils; single-coat application | Fully warrantable system via approved applicators; W.R. Meadows limited materials warranty | TDS |
| KNIGHTSHIELD KS-5200 Silicone Walk-Pad Roof CoatingW.R. Meadows | 93% by volume | 2 gal/100 sq ft (32 wet mils); broadcast KS-6000 granules at 18 lb/100 sq ft for traction | Component of warrantable KNIGHTSHIELD systems | TDS |
Specs from published manufacturer data sheets — confirm current specifications with the manufacturer.
Real silicone projects on RCN.
KNIGHTSHIELD Silicone Replaces a Failing Acrylic Coating in Huntsville AL
A Huntsville strip mall's eroding acrylic roof coating was trapping moisture against the metal panels; Arkbow…
Foam and Silicone Rebuild a Tornado-Damaged Million-Square-Foot Warehouse Roof in Garland TX
After an EF-2 tornado tore into a 1 million sq ft Garland warehouse, contractors rebuilt the…
TPO Roof Restoration at a Regional Airport Terminal in Middletown PA
A 14,000 sq ft TPO roof on a Pennsylvania regional airport terminal was restored with a…
Silicone Restoration Membrane Buys Midview High School 11 More Years, Grafton OH
West Roofing Systems installed a 25-mil silicone restoration membrane at Midview High School, matching an 11-year…
Stopping 50+ Leaks: Silicone Restoration at Vermillion Flooring, Springfield MO
A Missouri hardwood flooring plant with more than 50 active roof leaks was restored with a…
Silicone training & video series.
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Full video courses including surface prep, spray technique, mil verification and more are coming soon.
Find silicone contractors near you.
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Frequently Asked Questions
How long does a silicone roof coating last?
10–20+ years per cycle depending on the installed mil thickness and system spec — then the roof is cleaned and recoated with silicone to reset the clock.
Does silicone really work on roofs with standing water?
Yes — that’s its defining advantage. Cured silicone doesn’t absorb water and carries manufacturer ponding coverage no acrylic offers. Drainage should still be improved where practical.
Can you put silicone over an old TPO or EPDM roof?
Usually, and it’s one of the best restoration plays — after aggressive cleaning, an adhesion test, and the manufacturer’s primer where required.
Can silicone be recoated later with something else?
No — nothing bonds to cured silicone except more silicone. It’s a one-chemistry commitment from the first coat.
Is silicone slippery to walk on?
When wet, yes. Professional installs add granulated walk pads on every service path.
How much does a silicone system cost?
Roughly $3.00–$6.00 per square foot installed — typically one-third to one-half of replacement cost.
The full silicone series.
- The Silicone Crash Course — start hereYou are here
- Acrylic vs Silicone: Which Wins for Your RoofComing soon
- Cost: What You’ll Actually PayComing soon
- Ponding Water: Why Silicone Owns Flat RoofsComing soon
- Application: Coating TPO & EPDM RoofsComing soon
- Failures & TroubleshootingComing soon
- Coverage, Thickness & LifespanComing soon