Commercial Roof Repair: Signs, Costs, and When to Call a Professional

Every commercial roof will need repair at some point during its service life. Weather damage, material aging, foot traffic, and the constant stress of thermal cycling all take their toll over time. The question is not whether your roof will need attention, but when, and how you respond to that need will determine whether you spend a modest amount on a targeted fix or face a far more expensive problem down the road.

At Windward Roofing & Construction, commercial roof repair is one of the most common services we provide. After 40 years of diagnosing and fixing roof problems across every major roofing system, we have a clear picture of what causes commercial roofs to fail, how much repairs typically cost, and when it makes more sense to invest in replacement rather than continuing to patch an aging system. This guide shares that experience to help you make smart decisions about your building's most critical protective barrier.

Common Commercial Roof Problems

Roof Leaks

Leaks are the most obvious and urgent commercial roof problem. Water infiltration can damage inventory, equipment, electrical systems, interior finishes, and structural components. It also creates conditions for mold growth that can affect indoor air quality and create health concerns for building occupants.

Identifying the source of a commercial roof leak can be surprisingly difficult. Water that enters the roof assembly at one point often travels horizontally along the deck, insulation layers, or structural members before dripping through the ceiling at a location far from the actual breach. This is why professional leak investigation is essential. Experienced roof technicians use visual inspection, moisture surveys, and sometimes infrared imaging to trace the leak back to its point of entry.

The most common leak locations on commercial roofs are flashings around penetrations (pipes, vents, conduit, HVAC curbs), membrane seams, roof drain connections, parapet wall junctions, and areas of ponding water. In our experience, over 80 percent of commercial roof leaks originate at flashings or seams rather than in the field of the membrane itself.

Ponding Water

Ponding water is standing water that remains on the roof surface for 48 hours or more after the last rainfall. While it may seem harmless, ponding creates multiple problems. The weight of standing water stresses the roof structure. Prolonged water contact accelerates membrane degradation and can void certain warranty coverages. Ponding areas attract debris, promote biological growth, and create conditions where even minor membrane imperfections lead to leaks.

Ponding is caused by clogged drains, insufficient roof slope, settled or compressed insulation, and structural deflection. The solution depends on the cause. Drain clearing is simple and inexpensive. Correcting slope issues may require installing tapered insulation or adding additional drains, which is more involved but still far less costly than the damage ponding causes if left uncorrected.

Membrane Damage

The roofing membrane is the primary waterproofing layer, and damage to it compromises the entire system. Common types of membrane damage include punctures from dropped tools or sharp objects, tears from wind-blown debris, abrasion from foot traffic, blistering from trapped moisture within the roof assembly, and surface cracking or crazing from UV exposure and aging.

On single-ply membrane roofs (TPO, EPDM, PVC), punctures and tears are usually repairable with patches and welding or adhesive. On built-up and modified bitumen roofs, damaged areas can be cut out and rebuilt with compatible materials. The critical factor is prompt repair. A small puncture that costs $300 to fix today can lead to saturated insulation, deck damage, and interior water damage costing $10,000 or more if ignored.

Flashing Failure

Flashings seal the vulnerable transitions between the roof membrane and vertical surfaces like parapet walls, equipment curbs, expansion joints, and pipe penetrations. These areas are subjected to more stress than any other part of the roof because they must accommodate differential movement between the roof plane and the vertical structure.

Flashing failure manifests as separation from the wall or curb surface, cracking or splitting in the flashing material, deteriorated sealant at metal flashing joints, corrosion on metal flashings, and membrane flashings that have become brittle or lost adhesion. Because flashings are responsible for the majority of commercial roof leaks, keeping them in good condition is one of the most cost-effective maintenance investments you can make.

Open or Failed Seams

Every commercial roof has seams where membrane sheets overlap and are joined together. On TPO and PVC roofs, seams are heat-welded. On EPDM roofs, seams are sealed with adhesive or tape. On built-up roofs, layers overlap during the application process. Over time, seams can open due to thermal cycling, membrane shrinkage, poor original welding or adhesion, or wind uplift stress.

Open seams allow water to enter the roof assembly along the length of the opening, potentially causing widespread damage. Seam repairs on heat-welded membranes (TPO, PVC) involve re-welding the affected area. EPDM seam repairs require cleaning, priming, and applying new seam tape or adhesive. In all cases, the repair should be performed by a contractor experienced with the specific membrane system.

Signs Your Commercial Roof Needs Repair

Some roof problems are immediately obvious, while others develop gradually and may not be apparent until significant damage has occurred. Here are the warning signs that should prompt a professional roof inspection:

Interior signs:

• Water stains on ceilings or walls, even if they appear dry
• Active dripping or water intrusion during or after rain
• Musty or moldy odors, particularly near exterior walls or in top-floor spaces
• Unexplained increases in energy bills, which may indicate wet insulation losing its thermal value
• Peeling paint or bubbling wallboard on interior walls near the roofline

Exterior signs visible from the roof:

• Standing water 48 hours after rainfall
• Visible tears, punctures, or holes in the membrane
• Blistering or bubbling on the membrane surface
• Flashing that has separated from walls, curbs, or penetrations
• Missing, cracked, or deteriorated sealant
• Vegetation growing on the roof surface
• Sagging or visible deflection in the roof deck
• Accumulated debris blocking drains or scuppers
• Exposed or corroded fasteners on metal roofing or exposed-fastener systems

Repair Costs: What to Expect

Commercial roof repair costs vary significantly based on the type of damage, the roofing system, accessibility, and the urgency of the repair. Here are general cost ranges based on our experience across thousands of repair projects.

Minor repairs ($300 to $1,500): Small puncture patches, minor flashing resealing, individual sealant joint replacement, small seam re-welding, and drain clearing. These are the most common repair calls and are typically completed in a single visit.

Moderate repairs ($1,500 to $5,000): Larger membrane patches, multiple flashing repairs, drain replacements, localized insulation replacement where moisture has been confirmed, and more extensive seam work. These repairs may require a partial day to a full day on site.

Major repairs ($5,000 to $20,000+): Large-scale membrane replacement covering a significant portion of the roof, structural repairs to damaged decking, complete flashing replacement around multiple penetrations, and repairs involving specialized access equipment for tall or difficult-to-reach buildings.

Emergency repairs: Service calls outside normal business hours, during active storms, or requiring immediate response to prevent ongoing damage typically carry premium pricing of 1.5 to 2 times standard rates. Despite the premium, emergency repairs are almost always worth the cost because they prevent the exponential escalation of damage that occurs when water continues to infiltrate the building.

Repair vs. Replace: Making the Right Decision

One of the most important questions building owners face is whether to continue repairing an aging roof or invest in a full replacement. There is no single answer that fits every situation, but there are clear guidelines that can help you make a financially sound decision.

Repair typically makes sense when:

• The roof is less than 15 years old and in generally good condition
• Damage is localized to specific areas rather than widespread
• The underlying insulation is dry and performing well
• Total repair costs are less than 25 to 30 percent of replacement cost
• The roof has significant remaining useful life based on professional assessment
• The building is planned for sale or redevelopment within 5 to 7 years

Replacement typically makes sense when:

• The roof has reached or exceeded its expected service life
• Repairs are becoming frequent and increasingly expensive
• Damage is widespread across the membrane, flashings, and insulation
• Moisture surveys reveal saturated insulation across large areas
• The roof system no longer meets current energy code requirements and a re-roof offers the opportunity to upgrade insulation
• Total accumulated repair costs over the next 5 years are projected to exceed 40 to 50 percent of replacement cost

A professional roof inspection with a core cut analysis (to check insulation conditions) and a moisture survey provides the data needed to make this decision with confidence. We always recommend obtaining this information before committing to either extensive repairs or full replacement.

Emergency Roof Situations

Certain roof problems require immediate attention because they pose safety risks, threaten building contents, or will escalate rapidly if not addressed. Emergency roofing situations include:

• Active leaks during rain that are causing water damage to building contents, equipment, or electrical systems
• Storm damage that has created large openings in the membrane, displaced flashings, or removed sections of roofing material
• Structural concerns such as visible sagging, unusual sounds from the roof structure, or signs that the roof may be approaching its load capacity during snow events
• Wind damage to edge metal or fascia that could become projectiles in continued high winds, endangering people and property below
• Fire damage from rooftop equipment, lightning strikes, or adjacent building fires

In emergency situations, the priority is making the building safe and watertight as quickly as possible. This often involves temporary measures such as emergency tarping, temporary patches, or emergency drain clearing, followed by a permanent repair once conditions allow proper work.

Windward Roofing provides 24/7 emergency roofing services. Our emergency response team is equipped to reach your building quickly and take the immediate steps needed to protect it, followed by a thorough assessment and permanent repair plan once the emergency is stabilized. Call our emergency line at (844) 880-8844 for immediate assistance.

Choosing the Right Repair Contractor

The quality of a commercial roof repair depends heavily on the contractor performing the work. An improperly executed repair can actually make the problem worse by trapping moisture, creating new stress points, or using incompatible materials that damage the existing membrane.

Essential qualifications for a repair contractor:

• Experience with your specific roofing system (TPO, EPDM, BUR, modified bitumen, metal, or PVC)
• Manufacturer certifications that ensure they use approved materials and methods
• Adequate insurance coverage to protect your property
• A track record of quality repair work, not just new installations
• The ability to diagnose the root cause of the problem, not just address the visible symptoms
• Written documentation of the repair including scope, materials used, warranty coverage, and photographs

Avoid the temptation to use a general handyman or maintenance worker for roof repairs. Even seemingly simple fixes require knowledge of membrane compatibility, proper surface preparation, and correct application techniques. A repair that looks adequate from the ground may fail within months if it was not performed correctly.

Protecting Your Investment

Commercial roof repairs are an inevitable part of building ownership, but they do not have to be disruptive or unreasonably expensive. The keys to managing repair costs are regular professional inspections that catch problems early, prompt response to any damage or leak activity, working with a qualified contractor who diagnoses root causes rather than just treating symptoms, and maintaining detailed records of all repairs and inspections.

Windward Roofing & Construction provides comprehensive commercial roof repair, inspection, and maintenance services across Illinois, Wisconsin, Michigan, Indiana, and Florida. Whether you have an active leak that needs immediate attention or want to establish a proactive maintenance program that minimizes future repair costs, our team has the experience and expertise to help. Contact us for a consultation, or call our 24/7 emergency line when you need immediate assistance.

Frequently Asked Questions