Overview

In this blog, National Coatings Of Canada Inc explains what routine commercial roof coating maintenance involves, which changes deserve attention, and when repairs or recoating may be appropriate.

Highlights

Inspecting roof coatings
Cleaning coated roofs
Maintaining proper drainage
Protecting vulnerable roof details
Repairs and recoating

Introduction

A commercial roof coating can appear intact from the ground while developing wear or damage that's only visible up close. Dirt and debris can accumulate, drainage paths can become obstructed, and vulnerable areas around seams, flashings, and rooftop equipment can deteriorate over time.

Maintaining your commercial roof coating involves regular inspections, appropriate cleaning, clear drainage paths, and timely repairs when damage develops. The maintenance required depends on the coating material, roof design, and conditions at your property. Understanding these factors can help you recognize potential problems and determine when professional attention is necessary.

What Should You Check During a Roof Coating Inspection?

Regular inspections help identify damage or deterioration before it compromises the coating's ability to protect the underlying roof. While some problems are visible across larger sections of the roof, others develop around seams, flashings, fasteners, and rooftop equipment, where movement or physical damage can affect the coating.

An inspection should cover the overall condition of the coated surface, including areas where the coating may have worn away, separated from the substrate, or sustained damage. It's also important to distinguish cosmetic changes from conditions that could allow moisture to reach the roofing materials beneath.

Look for the following signs:

Cracking: Visible splits or breaks in the coating surface
Peeling: Areas where the coating appears to be separating from the material beneath it
Blistering: Raised areas that may need further examination to determine their cause
Punctures: Physical openings that could expose the underlying roofing material
Discoloration: Changes in appearance that may result from dirt, staining, or weathering rather than coating failure

When Should Inspections Take Place?

Spring and fall are practical times to inspect a commercial roof. Some manufacturers, including ASTEC, recommend inspections every six months, with additional checks of the protective finish. Inspection frequency also depends on the coating system, roof condition, environmental exposure, and warranty requirements. Additional inspections may be necessary after severe weather or rooftop equipment work.

Keeping photographs and records of previous inspections can help track changes over time and determine whether an area is deteriorating or remaining stable. Because commercial roofs present fall hazards and other safety risks, inspections requiring roof access should be performed by appropriately trained personnel using suitable safety measures.

How Should a Coated Commercial Roof Be Cleaned?

Leaves, branches, dirt, and other debris can accumulate on coated commercial roofs, particularly around rooftop equipment and drainage areas. Regular cleaning helps prevent buildup and makes it easier to identify damage or deterioration. However, cleaning methods must be compatible with the installed coating to avoid damaging its protective surface.

Removing Debris Without Damaging the Coating

Consider a low-slope roof with leaves gathered around a drain. Removing the obstruction may be all that's needed to restore normal water flow. Elsewhere, windblown debris might collect behind an HVAC unit or along a parapet, where it can remain long after the rest of the roof has cleared.

Debris should be removed carefully to avoid scraping or puncturing the coating. If dirt or buildup remains after loose material has been cleared, further cleaning should follow the coating manufacturer's recommendations, particularly when selecting cleaning products or equipment.

What About Dirt and Stains?

Ordinary dirt may be cosmetic, but recurring stains near exhaust outlets could indicate exposure to grease, chemicals, or other contaminants. Identifying and addressing the source is more effective than repeatedly washing the affected area.

Some reflective coatings may also lose part of their solar reflectance as dirt accumulates. Cleaning can help restore surface reflectance in suitable circumstances, although the result depends on the coating and the type of buildup.

How Does Drainage Affect Roof Coating Maintenance?

Proper drainage limits how long water remains in contact with a roof coating. This is particularly important on flat and low-slope roofs, which rely on subtle slopes to direct rainwater toward drains, scuppers, and other outlets.

Leaves and debris can obstruct these drainage paths, causing water to accumulate in areas where it would otherwise flow away. Keeping drains, gutters, and other outlets clear helps prevent unnecessary water buildup and allows the roof to drain as designed.

When Does Standing Water Need Further Attention?

A puddle immediately after rainfall isn't necessarily evidence of coating failure. What matters is how long the water remains, whether it repeatedly collects in the same location, and whether the installed coating is designed to withstand prolonged water exposure.

Persistent standing water, also called ponding water, can place additional demands on a coating system. Some products are formulated to tolerate these conditions, while others have limitations that can affect their performance or warranty coverage.

If water continues collecting after drainage openings have been cleared, the roof may have an underlying drainage or slope issue that requires professional attention. The coating's condition and suitability for prolonged water exposure should also be evaluated before determining whether corrective work is necessary.

Which Roof Details Need Extra Attention?

Large, uninterrupted roof surfaces are relatively easy to observe. The more complicated areas are often the places where roofing materials meet, change direction, or surround equipment. These details deserve attention during inspections because they often experience greater movement, foot traffic, or maintenance activity that can affect the surrounding coating.

Seams, Flashings, and Penetrations

On metal roofs, panel seams, fasteners, and flashings require particular attention. Metal expands and contracts with temperature changes, creating movement that can place stress on these connections and their protective coatings over time. Because these connections and openings can provide pathways for water to reach the underlying roofing materials, maintaining their protective coating and reinforcement is especially important.

Low-slope membrane roofs have different vulnerable details, including seams, perimeter transitions, drains, and penetrations. Coating systems may use reinforcing fabrics, tapes, and waterproofing membranes to strengthen and seal these areas. During maintenance, it's important to check that these protective materials remain intact and securely bonded.

Visible separation, damaged reinforcement, exposed fasteners, or openings around penetrations may indicate that repairs are needed to maintain a watertight barrier.

Areas Around Rooftop Equipment

Areas around HVAC units, vents, and other rooftop equipment deserve attention because technicians may walk across the roof or move tools and replacement parts during servicing. These activities can expose nearby coatings to accidental physical damage.

After equipment work, checking the surrounding coating and flashing can help identify punctures, disturbed details, or other changes that may need professional attention.

When Does a Commercial Roof Coating Need Repairs or Recoating?

Not every sign of wear requires the same response. Small areas of damage may be suitable for localized repairs, while more extensive deterioration could warrant recoating larger sections of the roof. The appropriate approach depends on the extent and cause of the damage, the condition of the underlying roofing materials, and the coating system already in place.

When Are Localized Repairs Appropriate?

Localized repairs may be sufficient when damage is confined to a small area and the surrounding coating remains sound. The work depends on the problem and may involve more than simply applying another layer of coating.

For example, a damaged seam or flashing may need to be resealed and reinforced with compatible waterproofing materials or fabric before the protective finish is restored. Punctures and cracks may require patching, while areas of peeling coating may need loose material removed and the surface prepared before a new application. Corrosion on metal roofing must also be addressed before the affected area is recoated.

If the underlying roofing materials are damaged or moisture has entered the system, those conditions need to be addressed before restoring the coating. Otherwise, applying new material over the affected area may conceal the problem without resolving it.

When Is Broader Recoating Necessary?

More complete recoating may be appropriate when deterioration extends across larger portions of the roof rather than remaining confined to isolated areas. Depending on the system, widespread weathering, loss of coating thickness, or declining adhesion may indicate that the protective finish needs renewal.

The process generally involves cleaning and preparing the existing surface, addressing damaged areas, and applying compatible coating layers to restore protection. Some systems are specifically designed for periodic renewal, allowing the existing roof to remain in service without a complete replacement.

However, visible aging doesn't automatically mean recoating is necessary. If the existing coating remains intact and continues to perform as intended, routine maintenance or isolated repairs may be sufficient. Conversely, extensive substrate deterioration or trapped moisture may require more substantial roofing work before recoating can be considered.

Why Compatibility Matters

A new coating must be compatible with both the existing coating system and the underlying roofing material. Different substrates, including metal, asphalt, and EPDM rubber, may require specific primers, base sealers, or surface preparation methods to achieve proper adhesion.

Applying an incompatible product or coating over an improperly prepared surface can lead to adhesion problems and premature deterioration. Existing warranties may also specify approved materials, application procedures, and maintenance requirements.

Before proceeding, a roofing professional should identify the existing system, evaluate its condition, and determine whether the proposed materials and application methods are suitable.

Keep Your Commercial Roof Coating in Good Condition

Regular maintenance helps preserve your commercial roof coating's protective function and identify problems before they worsen. Whether you need a professional coating inspection, localized repairs, or broader roof restoration, National Coatings Of Canada Inc can help you maintain and protect your existing roofing system.