How To Restore Your Leaky Commercial Roof


Learn How to Apply Sealant and Coating to Repair Industrial Roof Leaks and Protect them from the Elements

Because of its exposure to the elements, the roof is the most important—and most vulnerable—part of a building. Wind and rain, ice and snow, U.V., extreme heat or cold can all take their toll on roofs and cause leaks or other failures. Many building owners and managers assume that their best option to fix a leaky roof is to replace it altogether, but this is not always the case. In many circumstances, simpler, less expensive restoration processes can repair roof damage while strengthening the roof against future damage.

In this article, we’ll discuss the kinds of conditions that can cause roof damage, the comparative advantages of roof restoration or replacement, when to restore your roof, and the best sealant and coating products for restoring a damaged roof.


There are a number of environmental conditions that can cause wear or damage to industrial roofs. Each presents its own challenges.

Wind. Especially in places prone to high wind gusts or extreme weather events like tornadoes or hurricanes, wind can cause gradual or immediate damage to an industrial roof. High winds can weaken seams and fasteners and flying debris can cause direct structural damage to the roof.

Rain, Hail, and Snow. Environmental precipitation can wear on a roof in a number of ways. Rainfall can degrade roofing materials, while hail can dent metal roofs and cause other direct structural damage to other roof types; heavy snowfall accumulation can stress and weaken a roof and roof connections.

U.V. Ultraviolet radiation comes in its most intense natural form from the sun. U.V. rays, particularly those known as the “B” wavelengths are responsible for anything from skin cancers to the breakdown of most materials, unless protected. Original protections wear away, requiring the restoration of protection to prevent damages and ultimate destruction of more vulnerable materials such as those used in construction.

Heat. Over time, exposure to high temperatures cause stress to roofing materials, causing them to weaken and become more vulnerable.

Freeze/Thaw Cycles. Even small amounts of moisture can infiltrate the seams in a roof, and as that moisture expands and contracts with typical changes in weather and temperature, it can cause them to widen and weaken seams of all roofs and fasteners of metal that keep them tight, causing leaks, greater damages to underlying materials, and further exposure to the elements.


It’s commonly assumed that complete replacement is the best option for fixing an aging or leaky roof. In some cases it is, but restoration is often a more desirable alternative. If a roof has failed or fallen into total disrepair—for example if it is structurally unsound or if there is widespread damage or deterioration—then replacement is the only option. However, if the roof is only suffering from some damage, wear, or other issues of exposure, restoration can be a better alternative for a variety of reasons.


Cost. Roof replacement projects on industrial buildings are labor- and resource-intensive processes, and they can run into the tens to hundreds of thousands of dollars on even modest sized buildings. Building owners and managers must take into account the cost of materials, as well as labor, disposal, business interruptions, and other considerations. Premature replacement rather than maintenance, shortens the roof’s service life and makes the original investment a costlier one. The pattern of doing this starts a cycle of far greater costs with waste of money and resource.

Roof restoration, on the other hand, generally comes in at 1/3 or less of the cost of total replacement. This is because it is far less resource-intensive. Restoration requires fewer materials, man hours, and involves maintenance rather than replacement, and is far less disruptive to regular business operations. Moreover, it can save money down the road by strengthening a roof against future damage.

Efficiency. When only 10% of a roof is damaged, it doesn’t make sense to replace 100% of it. Because restoration projects can target damaged areas, they are far less wasteful.

Environmental Factors. Roof restoration requires less energy usage, resources, and landfill waste than roof replacement. Moreover, some roof coating products have been shown to reduce roof temperature. Not only does this reduce wear over time, it can reduce peak cooling demand by up to 15%, thereby reducing energy usage.

Sustainability. Roof restoration and maintenance, when done properly, can protect your roof against the elements and provide long-term solutions to normal aging. The typical commercial roof lasts about 20-30 years if properly maintained. Restoration can increase that lifespan by an additional 10 to 15 years or longer if well maintained.


When deciding whether it’s time to restore your roof, you should take into account a variety of factors:

Damage and Wear. This is the most obvious factor to think about when choosing whether to restore your roof. If your roof has leaks or other exposure issues, it is important to begin restoration as soon as possible in order to fix the problem and prevent further damage. Water that gets beneath roofing plies (non-metal roofs) quickly causes deterioration under the surface which must be corrected and all damp underlayment replaced, prior to sealing it with a coating. Note, however, that if the damage has gone too far—for example, if the majority of the roof is damaged, or the roof is compromised or not structurally sound—replacement may be necessary.

Condition. Even if your roof is not currently leaking, its state of repair may merit restoration. You may look for dryness, isolated splitting or cracks in the existing membrane, deteriorated flashings, and other signs of minor wear. With metal roofs it may be rust, missing fasteners, loosened or damaged panels – all of which are more easily addressed. Any of these signs should cause you to consider roof restoration. Deferred maintenance always results in added expense.

Water Ponding. Gathering water is a sign of deteriorating membranes or surfaces and is likely to cause serious damage down the road. Even if you apply a coating capable of withstanding ponding water, it will not correct any underlying damages and will exclude warranty coverage including any leaks caused by the compromised condition.

Odor or Mold. A musty odor from any roofing insulation, or visible mold on the roof’s underside, are signs of moisture infiltration and should likely be addressed with replacement.

Age. Most maintained commercial roofs will last from 20 to 30 years before requiring replacement. With timely restoration, it can last longer. When one replaces prematurely, rather than maintaining on an appropriate schedule, one dramatically cuts short the roof’s service expectancy and makes the original roof become costlier. However, restoring your roof before this age threshold can significantly lengthen its lifespan.

Time of Year. Roof restoration projects are best undertaken during the summer time This helps avoid coating over dew or frost. It also allows the installer to more easily check for moisture that can otherwise wind up trapped beneath the membrane and cause severe problems later on.


Once you have chosen to restore your roof, you should follow these steps to ensure that the job is done properly.


All roofs should first be inspected by a competent professional roofing contractor to be sure no problem goes overlooked. It is the independent installer’s responsibility to assure no moisture is beneath the roof, to identify all elements to repair or replace, and to review their recommendations with you.


Each project begins with accurate measurements. This means adjusting the surface area calculation for coating by the additional area caused by ribs or corrugation of metal panels. All seams and flashings are inspected. Areas of the roof surface that need special attention are noted. Information is recorded, and a complete plan is designed.


No restoration project begins until after a roof is thoroughly cleaned.

Prior to cleaning, a rust neutralizer and cleaner should be applied to all areas of metal showing signs of corrosion. High-pressure washing removes all dirt and any failed coatings. Blowers and push brooms should be used wherever possible on membraned roofs to avoid leaks or exposure to moisture.

Finally, isolated areas are replaced if needed prior to installing the protective system. This should be minimal for roofs maintained on a timely basis.


Prior to coating, you should be sure to check and seal seams. On metal, this includes tightening loose fasteners, replacing them and adding if necessary. Critical areas such as flashings, HVAC units, curbs, stacks and vents are treated with a thick mastic. All seams and fasteners are sealed and a special reinforcing membrane is applied where extra strength is needed.

Bituminous roofs often benefit by first applying an appropriate primer. This is usually spray applied using a low-pressure sprayer. On smaller roofs, this is done with a pump-up sprayer carried by the applicator. Some metal coatings, such as those containing water, will require a primer if the desire is to prevent rust. Do not assume. Make certain the coating you use for metal specifically says it will prevent rust if this is concern for you.


Gutters can be treated with specialized water-repellent coatings to prevent rust and other moisture-related deterioration. As with the rest of the roof, gutters should be cleaned, prepared, and, where necessary, repaired before application.


Finally, the roof is ready for the seal-coating application. Once cleaned and dried, usually overnight, the roof is ready for the base coat. The entire roof should be coated with a base coat. This leaves a seamless, air-tight protective foundation for the final coating finish once dried.

On larger projects, all coatings are most economically installed using an airless sprayer. Smaller jobs can be handled efficiently using ordinary long-handled paint rollers. In all cases on granule or foam covered surfaces the base coat layer is back rolled while wet. This assures a proper thorough seamless bond of coating protection that leaves no gaps.

Since uniform and appropriate coating thicknesses are required for best performance, most roof coating manufacturers recommend two coats be applied to a commercial roof. This helps prevent trouble areas that otherwise might occur with a single coat application.

The finished coat of super elastomeric coating is now installed using either spray or roller. Because this coat involves no back-rolling application it is simple and efficient. The roof is now complete.


Manufacturers make all sorts of claims as to the quality of their products, often emphasizing various properties. Unfortunately, there is no single tested property to consider when comparing products. However, ASTM International has identified some factors to be aware of:

  • Do sellers report dependable moisture absorption resistance?
  • Do sellers report actual adhesion strength?
  • Does the product hold up under various conditions (and, particularly, the conditions under which you will need it to hold up)?
  • Does the product hold up under environmental stress?
  • How well does the coating age and change over time? Is it durable? How quickly?
  • Can the coating handle all the conditions which may be present?

Additionally, you should do some research into who makes the product. There are many so-called “manufacturers” who simply buy cheap, generic products and then sell them under their brand. Words like “supplier of”, or those not specifically using the words “manufactured by”, are good indicators you are not buying from the real maker and may not be around when you need them.

You can see how Topps products stack up to others by clicking here.


Though sometimes full roof replacement is necessary, restoration is a good alternative that offers many benefits, including saving on costs, savings on waste, savings on environment and the cooling costs of your building, increasing efficiency with fewer future maintenance issues, and extending the life of your roof. To decide which option is best for you, take into account the extent of wear on your commercial roof and determine your needs. Check out your installer to be certain they can recognize and handle what your roof may need. Finally, when you’ve chosen to restore or replace, be sure to do your research to ensure that you use the products that best suit your needs. Just as a chain is only as good as its weakest link – a coating is only as good as its weakest physical property.

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