Chronic leaks on a large commercial flat roof have a way of consuming maintenance budgets slowly and steadily — each repair buying a few more months before the next call comes in. This DeLand business owner had been living that reality for years, watching repair costs accumulate while a full TPO roof replacement remained financially out of reach. DeSantis Roofing delivered a solution that changed the equation entirely: a GAF Unisil silicone coating system applied over the existing membrane at approximately half the cost of full replacement, backed by a 20-year warranty that finally closes the door on the leak cycle that had defined this roof for too long.
The before photo shows the original roof surface — a large, heavily trafficked commercial flat roof with seam tape lines, surface oxidation, and the worn appearance of a membrane that had been repaired and re-repaired across its expanse. The completed photos, shot at both sunset and midday, reveal a seamless bright white silicone surface stretching across the entire roofline with every HVAC unit, penetration, and parapet wall sealed continuously into the new coating system. Understanding what made silicone coating the right answer — technically and financially — helps commercial property owners facing similar situations see a path forward that doesn’t require replacing everything.
The Real Cost of Ongoing Leak Repairs
Repeated leak repairs on a commercial flat roof rarely fix the underlying problem — they address the symptom at its most recent failure point while the rest of the aging membrane continues deteriorating toward its next breach. Each service call, each patch, and each emergency response to interior water damage carries a cost that adds up across years of deferred investment. When those cumulative repair costs are totaled against the price of a permanent solution, the math often shifts dramatically in favor of acting comprehensively rather than continuing to patch.
For this DeLand property owner, the conversation with DeSantis Roofing reframed the choice from “can I afford to fix this roof” to “how do I stop spending money on repairs that don’t last.” The silicone coating system answered both questions simultaneously — delivering permanent waterproofing protection at a price point that worked within the budget available.
Why Silicone Coating Instead of TPO Replacement
A full TPO membrane tear-off and replacement on a commercial flat roof of this scale involves significant material and labor costs — stripping the existing membrane, disposing of it, installing new insulation if needed, and fully re-membraneing the deck. Silicone coating systems like GAF Unisil are specifically engineered to be applied over existing membranes in acceptable condition, eliminating the tear-off phase entirely and reducing both material costs and project duration dramatically. The result is a new, warranted waterproofing system installed over the existing substrate at roughly half the cost of starting over.
The key qualification for a coating system is that the existing membrane must be structurally sound enough to serve as a stable substrate — not saturated with moisture or delaminated from the deck below. This assessment, performed before the project began, confirmed that the existing membrane was a viable candidate for coating rather than replacement.
GAF Unisil Silicone Coating System
GAF’s Unisil silicone product is a commercial-grade, moisture-cure silicone coating designed specifically for low-slope and flat commercial roofing applications across Florida’s demanding climate. Silicone’s defining advantage over acrylic and other coating chemistries is its complete resistance to degradation from standing water — a condition that routinely occurs on flat commercial roofs where drainage moves slowly or ponding develops in low areas. Where acrylic coatings soften, blush, and eventually fail when water stands on them, silicone maintains full adhesion and waterproofing integrity regardless of how long water remains on the surface.
The bright white finish the GAF Unisil system produces delivers measurable energy performance benefits alongside its waterproofing function. Florida commercial buildings under a reflective white roof surface see significantly reduced membrane temperatures on summer days — sometimes 50 to 80 degrees cooler than dark membrane alternatives — which directly lowers the cooling load the building’s HVAC units carry through the long Florida summer.
Surface Preparation and Application
The original membrane visible in the before photo shows the seam tape lines, surface oxidation, and wear patterns typical of an aging commercial flat roof that has been in service for years without a comprehensive treatment. Proper preparation before silicone application requires cleaning the surface thoroughly, treating any compromised seams or blisters, and ensuring the membrane is dry and free of contamination that would prevent adhesion. These preparation steps determine whether the silicone coating bonds permanently to the substrate or eventually peels away from inadequately prepared areas.
The coating was applied in multiple passes to achieve the film thickness GAF specifies for warranty qualification, with each HVAC curb, pipe penetration, and parapet termination receiving detailed attention to ensure the seamless membrane extends continuously through every vulnerable transition point. These detail areas — not the open field — are where flat roof waterproofing systems most commonly fail, making thorough coverage at every penetration as important as the broad field application.
HVAC Units and Penetration Sealing
The completed photos show multiple large HVAC package units distributed across the roof surface, each sitting on curbed bases that were fully sealed into the silicone coating system. Commercial roofs with multiple HVAC units present numerous penetration and curb seal details that must be executed correctly to maintain the waterproofing integrity of the coating across the full surface. Each curb received silicone coating run up and over its base continuously, eliminating the gap between field membrane and equipment base that older repairs typically leave as recurring leak points.
Additional plumbing vents and smaller penetrations scattered across the field received individual boot-style sealing into the coating, ensuring no unprotected metal-to-membrane transitions remain anywhere on the finished surface. This comprehensive penetration treatment is visible in the completed photos as the clean white coating wrapping each base uniformly.
The Completed Roof and 20-Year Warranty
The sunset and midday photos of the completed coating installation capture the scale of this project — a large commercial flat roof stretching from the distinctive arched blue parapet features at one end to the full rear expanse of the building, every square foot covered in consistent bright white GAF Unisil silicone. The parapet walls received coating treatment as well, their vertical faces and cap surfaces sealed into the system to prevent the wall-top water entry that bypasses field membrane protection entirely. The transformation from the worn, seam-taped original surface to the seamless white finished system is visible even without a direct side-by-side comparison.
The 20-year warranty backing this installation means the business owner has two decades of manufacturer-supported protection against the leaks that consumed years of maintenance budget before this project. For approximately half the cost of a TPO tear-off and replacement, the property now carries the same warranty period a new roof would provide.
Commercial Roof Coating Solutions from DeSantis Roofing
Commercial property owners facing chronic flat roof leaks don’t always need to replace the entire roof to achieve permanent protection — but they do need a contractor with the expertise to assess the existing membrane honestly and execute a coating system to manufacturer specifications. DeSantis Roofing serves DeLand, Apopka, and the surrounding Central Florida area with commercial roofing solutions that match the right system to each building’s condition and budget, from GAF Unisil silicone coatings to full TPO replacements when the situation requires it. Contact DeSantis Roofing at (321) 501-6220 to schedule your commercial roof assessment and find out whether a coating system is the right solution for your building.