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Roof Coating: GAF HydroStop® System

Extend. Protect. Restore—Without a Full Tear-Off.
Can a roof coating replace a full commercial roof replacement? Often it can. If the deck and insulation underneath are still sound, the GAF HydroStop system can go over an existing flat or low slope roof, seal it end to end and add years of service with no tear off. It costs far less than a replacement, keeps the building open while the work happens, and keeps the old roof out of a landfill. J. Carnes & Son inspects the roof first and will tell you plainly whether coating is the right call or whether the roof is too far gone. Free inspections at 603-686-7763.

The short version

  • GAF HydroStop is a liquid applied acrylic system: a primer, a reinforcing fabric and multiple coats that cure into one seamless waterproof membrane over the roof you already have.
  • It is especially effective over commercial metal roofs, where seams, fasteners and expansion movement are where the leaks start.
  • No tear off means no dumpsters, no disruption to the business below, and a job measured in days rather than weeks.
  • Coatings are commonly treated as a repair expense rather than a capital improvement. Ask your accountant, and ask us for a free roof evaluation to see if your roof qualifies.

For commercial property owners looking to extend the life of an aging roof without the cost and disruption of a full replacement, the GAF HydroStop® PremiumCoat System offers a smart, efficient alternative. This liquid-applied roofing system is engineered for restoration, delivering long-term waterproofing, energy savings, and serious tax advantages—all while avoiding the complexity of a traditional re-roof.

What is the HydroStop® System?

Seamless Protection. Built to Last.

HydroStop® is a high-performance liquid-applied acrylic roofing system designed to create a seamless, fully adhered waterproof barrier over existing roofing surfaces—especially commercial metal roofs. The system includes a primer, reinforcing fabric, and multiple layers of acrylic coating, forming a durable, reflective surface that protects against UV, ponding water, and thermal movement.

Whether your roof is aging, leaking, or simply underperforming, HydroStop® gives it new life—without disrupting your business or breaking the budget.

Commercial roof coating application by J. Carnes & Son
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Ideal for Commercial Metal Roofs

No tear-off. No disruption.
All performance.

The GAF HydroStop® system is especially effective over commercial metal roofing systems, where seams, fasteners, and expansion movement often lead to leaks and deterioration over time. Our coating system bridges gaps, seals penetrations, and stops rust in its tracks, restoring performance and extending roof life with minimal downtime.

Ideal for Commercial Metal Roofs

No tear-off. No disruption.
All performance.

The GAF HydroStop® system is especially effective over commercial metal roofing systems, where seams, fasteners, and expansion movement often lead to leaks and deterioration over time. Our coating system bridges gaps, seals penetrations, and stops rust in its tracks, restoring performance and extending roof life with minimal downtime.

coatings
WHY CHOOSE ROOF COATINGS?

Restoration Over Replacement. Better Value. Smarter Tax Treatment.

Unlike a full roof tear-off, the HydroStop® system qualifies as a restoration and repair process not a capital improvement. That distinction matters—especially at tax time.

Tax Benefits:

  • Expensable in the Year of Application

The IRS typically treats roof coatings as a repair or maintenance expense, similar to painting a building. That means the full cost can often be deducted in the same year, rather than depreciated over decades.

  • Avoids Reclassification as a New Roof

Since coatings don’t constitute a full roof replacement, they may not trigger the regulatory and permitting requirements that a tear-off would—streamlining your capital planning.

Practical Benefits:

  • Extends the Life of the Existing Roof

HydroStop® coatings can add years—often a decade or more—to your current roof, delaying costly replacement and minimizing disruption to your operations.

  • Reduces Energy Costs

The white, reflective surface lowers roof temperatures, reduces HVAC strain, and can cut cooling costs significantly in warm months.

  • Watertight, Seamless Finish

No seams. No fasteners. No exposed gaps. Just a solid, monolithic membrane that flexes with your roof and holds up under stress

  • Low Impact, Fast Turnaround

Minimal noise, no interior exposure, and fast installation—ideal for occupied commercial spaces or buildings with sensitive operations.

Why Choose J. Carnes & Son Roofing?

GAF Certified Installers

Trained and certified to install the HydroStop® system to manufacturer standards, ensuring full warranty protection and optimal performance.

In-House Equipment & Capabilities

We own our industrial-grade coating sprayers—minimizing delays and maximizing job-site control.

Commercial Roofing Experts

We work directly with property managers, facilities directors, and building owners to deliver clear communication, accurate scopes, and professional-grade results—on time and on budget.

What is the GAF HydroStop PremiumCoat system?

Direct answer: HydroStop is a fluid applied acrylic roofing system that restores an existing roof instead of replacing it. A primer bonds to the old surface, a polyester reinforcing fabric is embedded across every seam and penetration, and multiple finish coats cure into a seamless, reflective, fully adhered membrane. The result stops leaks, stops rust on metal roofs and drops rooftop temperatures in summer.

The strength of the system is the fabric. Paint on coatings crack where the roof moves. HydroStop puts a reinforcing layer across every seam, fastener head and curb, so the membrane stretches with the building through a New England freeze and thaw cycle instead of splitting. We are GAF certified installers, which means the installation is done to spec and the manufacturer warranty is registered in your name.

Which roofs are good candidates for a coating?

Direct answer: Commercial metal roofs are the best candidates, along with sound EPDM, TPO and modified bitumen roofs that are aging but dry. The test is what is underneath. If moisture readings and core samples show a dry deck and insulation, a coating adds a decade or more of life. If the roof is saturated, a coating only hides the problem and we will tell you so.

A metal roof that is rusting at the fasteners and weeping at the laps is exactly what HydroStop was built for. The fabric bridges the seams, the coating seals the screws, and the rust stops. A membrane roof with ponding water and wet insulation is not a candidate no matter how good the coating is. We take the readings before we quote, because the wrong recommendation costs you twice.

How long does a roof coating last, and can it be recoated?

Direct answer: A properly installed HydroStop system typically adds ten years or more to a commercial roof, and it can be recoated at the end of that period without another tear off. That makes it a renewable roof. Each recoat is a fraction of the cost of the original application and far less than a replacement, which is why many owners never go back to a conventional re roof.

The finish coat takes the weather. The reinforced base underneath keeps doing its job. When the finish shows wear, a cleaning and a fresh topcoat restore the reflectivity and the warranty. For owners with several buildings, that turns roofing from a series of capital projects into a predictable maintenance line. We inspect coated roofs seasonally and document each visit with photos so you can plan the recoat years ahead.

Roof Coating: Your Questions, Answered

How much does a roof coating cost compared to replacement?

A HydroStop restoration typically costs a fraction of a full tear off and replacement because there is no demolition, no disposal and far less labor. The exact number depends on roof size, condition and the amount of seam and penetration work. Every evaluation ends with a free written estimate.

Can HydroStop be applied over a metal roof?

Yes, and metal roofs are where it performs best. The reinforcing fabric bridges the seams, the coating seals every fastener, and the acrylic stops existing rust from spreading. It is the standard fix for a leaking commercial metal roof that is structurally sound.

Will a roof coating disrupt my business?

Very little. There is no tear off, no dumpsters and no open roof overnight. Most coating projects take days rather than weeks, the work is quiet, and we schedule around your hours. Tenants usually notice the cooler building before they notice the crew.

Is a roof coating a repair or a capital improvement for tax purposes?

Coatings are commonly treated as a repair and maintenance expense rather than a new roof, which can mean the cost is deductible in the year of application instead of depreciated over decades. Confirm the treatment with your accountant for your situation.

Restore Your Roof.
Improve Your Bottom Line.

Contact us today to schedule a roof evaluation and find out if your property is a candidate for the GAF HydroStop® PremiumCoat System.

Save money, extend the life of your roof, and protect your investment—without tearing it all off!