Regular professional roof inspections are the cornerstone of any effective commercial roof management strategy. They catch problems early, extend the roof's service life, maintain warranty compliance, and give building owners the information they need to budget accurately for future maintenance and replacement. Yet many building owners treat inspections as an afterthought or skip them entirely, discovering problems only when water starts dripping through the ceiling.
At Windward Roofing & Construction, our inspection teams evaluate commercial roofs across the Chicago metropolitan area and beyond every week. Over 40 years, we have refined our inspection process to cover every component that affects a roof's performance and longevity. This guide walks you through the 15 items our inspectors check during a comprehensive commercial roof assessment, explaining what they are looking for, why it matters, and what common problems look like in each area.
1. Overall Membrane Condition
The field membrane is the primary waterproofing layer of the roof, and its general condition sets the baseline for the entire inspection. Inspectors evaluate the membrane for signs of aging, weathering, and damage across the full roof area.
On single-ply membranes like TPO and EPDM, inspectors look for cracking, crazing, chalking, discoloration, surface erosion, and loss of flexibility. On built-up and modified bitumen roofs, they check for alligator cracking, blistering, ridging, and gravel displacement. Any of these conditions indicate that the membrane is aging and may be approaching the point where repairs become less effective and replacement should be planned.
2. Seam Integrity
Membrane seams are where sheets of roofing material overlap and are joined together. They are inherently vulnerable because they represent a transition in the waterproofing layer. Inspectors examine seams closely for signs of separation, peeling, fishmouthing, or bridging.
On TPO roofs, heat-welded seams are tested by probing with a blunt tool to confirm the weld is fully adhered. On EPDM roofs, adhesive and tape seams are checked for edge lifting and adhesive deterioration. Seam failures are among the most common causes of roof leaks, and catching early separation before it becomes an active leak is one of the most valuable outcomes of a regular inspection program.
3. Flashing Details
Flashings are the waterproofing components at every transition point on the roof, including where the membrane meets walls, curbs, equipment supports, pipes, and roof edges. Because flashings are subjected to more thermal stress and movement than the field membrane, they are typically the first components to fail.
Inspectors examine wall flashings for separation from the substrate, cracking, and deterioration of counter-flashing seals. Equipment curb flashings are checked for the same issues plus any signs of ponding water against the curb. Pipe and penetration flashings are evaluated for sealant condition and membrane adhesion. Flashing issues found during inspections can usually be repaired at minimal cost, preventing the expensive leak damage that occurs when they are left unaddressed.
4. Penetration Seals
Every pipe, vent, conduit, and mechanical element that passes through the roof creates a penetration that must be properly sealed. Inspectors individually examine each penetration for the condition of the flashing, sealant, and any boots or collars used to waterproof the opening.
Common problems include cracked or shrunk sealants, displaced pipe boots, membrane separation from the penetration, and improperly sealed additions that were made after the original installation. Buildings with numerous rooftop penetrations, such as those with extensive HVAC systems, require particular attention in this area.
5. Drainage Systems
Effective drainage is essential for commercial roof performance and longevity. Inspectors evaluate all drainage components, including internal drains, scuppers, gutters, and downspouts, for proper function and condition.
Internal drain bowls are checked for debris accumulation, secure clamping ring connections, and intact strainer baskets. Scuppers are examined for blockage and proper clearance. Gutters and downspouts are assessed for physical condition, proper attachment, and clear flow paths. Inspectors also look for evidence of water backup or overflow marks that indicate drainage capacity problems.
6. Ponding Water
Ponding water, defined as water that remains on the roof surface for more than 48 hours after the last rainfall, is a serious concern for commercial roofs. It accelerates membrane deterioration, adds structural load, creates conditions for vegetation growth, and can void warranty coverage.
Inspectors identify ponding areas by looking for staining patterns, algae growth, debris rings, and sediment deposits that indicate where water regularly collects. During inspections conducted while the roof is wet, ponding areas can be directly observed and measured. When ponding issues are identified, the inspector will recommend solutions such as additional drains, tapered insulation, or cricket installations to redirect water flow.
7. Edge Metal and Coping
The perimeter of the roof is secured by edge metal, coping caps, or gravel stops that protect the roof edge from wind uplift and water intrusion. These components are subjected to significant wind forces and thermal movement and require regular evaluation.
Inspectors check for loose or displaced sections, open joints between coping pieces, missing or failed sealants at joints, corrosion on metal components, and proper anchorage to the building structure. Edge metal failures can allow wind-driven rain to enter the roofing assembly from the perimeter and are a common source of leaks that can be difficult to trace.
8. Parapet Walls and Counterflashings
Parapet walls, the low walls that extend above the roof surface around the building's perimeter, present their own set of inspection concerns. The counterflashings embedded in or attached to these walls are critical waterproofing components.
Inspectors examine the parapet wall surfaces for cracking, deteriorating mortar joints, and spalling masonry that could allow water to enter the wall system and migrate to the roof level. Counterflashings are checked for secure attachment, adequate overlap with the base flashing, and sealed joints. The coping on top of the parapet is evaluated for proper slope, sealed joints, and secure attachment.
9. Roof-Mounted Equipment
HVAC units, exhaust fans, satellite dishes, lighting equipment, and other roof-mounted installations are common on commercial buildings. Each piece of equipment interacts with the roofing system and creates potential maintenance concerns.
Inspectors evaluate the condition of equipment supports and curbs, ensuring they are properly flashed and elevated above the roof surface. They check for vibration damage from mechanical equipment, condensation or discharge issues from HVAC units, and debris accumulation around equipment that impedes drainage. Equipment that was added after the original roof installation receives special attention to verify that the penetrations and support structures were properly waterproofed.
10. Insulation Condition
The roof insulation sits beneath the membrane and is not visible during a standard visual inspection, but its condition significantly affects the roof's thermal performance and structural integrity. Wet insulation loses its insulating value, adds significant weight to the roof structure, and accelerates membrane deterioration from underneath.
Inspectors assess insulation condition through several methods. Infrared thermography conducted after sunset on a clear evening can reveal areas of wet insulation that retain heat differently than dry insulation. Physical indicators visible from the roof surface, such as soft spots or areas where the membrane compresses underfoot, may suggest saturated insulation below. When conditions warrant, core sampling provides definitive information about insulation moisture content and condition.
11. Interior Indicators
A thorough commercial roof inspection does not stop at the roof surface. Inspecting the building's interior, particularly the top floor and any accessible attic or plenum spaces, reveals evidence of roof problems that may not yet be visible from above.
Inspectors look for water stains on ceiling tiles and structural members, discoloration or peeling paint on walls near the roofline, musty odors indicating moisture or mold, daylight visible through the roof deck, and signs of past leak repairs. These interior indicators often point to roof issues that need investigation from above and can help narrow the search area for active leak sources.
12. Structural Deck Condition
The structural roof deck supports the entire roofing assembly and must be evaluated for signs of deterioration, damage, or distress. On metal deck roofs, inspectors check for corrosion, particularly in areas where moisture has been present. On concrete decks, they look for cracking and spalling. On wood decks, rot and structural weakening are primary concerns.
Deck evaluation from the roof surface is limited to observing deflection, soft spots, and other visible indicators. When interior access is available, inspectors can examine the underside of the deck directly. Any structural concerns identified during a roof inspection should be evaluated by a structural engineer before roofing work proceeds.
13. Expansion Joints
Large commercial roofs often incorporate expansion joints to accommodate thermal movement in the building structure. These joints are designed to flex as the building expands and contracts with temperature changes. If the expansion joint cover or flashing fails, it creates a direct path for water into the building.
Inspectors evaluate expansion joints for proper alignment, secure attachment at both edges, the condition of the flexible cover or bellows, and the integrity of any sealants. Expansion joints that have been pinched, stretched, or displaced indicate structural movement that may be affecting other parts of the roofing system as well.
14. Previous Repair Quality
Most commercial roofs that have been in service for several years will show evidence of past repairs. Inspectors evaluate these repairs for quality, effectiveness, and compatibility with the surrounding system.
Common issues with previous repairs include incompatible materials that can damage the existing membrane, patches that are too small or improperly adhered, excessive layers of sealant that mask rather than fix underlying problems, and repairs that fail to address the root cause of the original problem. Poorly executed past repairs often become future leak sources and may indicate areas where more comprehensive attention is needed.
15. Documentation and Photographic Record
The final element of a professional roof inspection is comprehensive documentation. A detailed inspection report with supporting photographs creates a permanent record of the roof's condition at a specific point in time.
Professional inspection reports should include an overview of the roof's general condition and estimated remaining useful life, photographs of each deficiency identified along with its location on the roof, prioritized recommendations categorized as urgent, short-term, and long-term, cost estimates for recommended repairs, and comparisons with previous inspection reports to track the roof's condition over time.
This documentation serves multiple purposes. It guides maintenance and repair budgeting, supports insurance claims for storm damage, satisfies warranty maintenance requirements, provides baseline data for tracking deterioration rates, and gives building owners objective information for replacement planning decisions.
The Value of Professional Inspections
Building owners sometimes question whether professional inspections are worth the cost when their maintenance staff can walk the roof and look for problems. While regular walkthroughs by maintenance personnel are valuable, they do not replace professional inspections for several reasons.
Professional inspectors have the training and experience to identify subtle signs of deterioration that untrained observers miss. They understand how different roofing systems age and can predict where problems are likely to develop next. They have access to specialized equipment like infrared cameras and electronic leak detection tools. And they provide objective, documented assessments that carry weight with insurance adjusters, warranty administrators, and potential building buyers.
At Windward Roofing & Construction, our inspection services provide building owners with the actionable intelligence they need to manage their roofing assets effectively. Whether your building needs a routine biannual inspection, a post-storm assessment, or a comprehensive evaluation ahead of a planned maintenance program, our team delivers thorough, clearly documented inspections that give you a complete picture of your roof's condition.
Ready to schedule an inspection for your commercial building? Contact Windward Roofing today. Our experienced inspectors serve building owners throughout the Chicago area and can typically schedule an inspection within one to two weeks. For emergency situations, our team is available 24/7.
Frequently Asked Questions
Commercial roofs should be professionally inspected at least twice per year, typically in spring and fall. Spring inspections identify any damage from winter weather before summer storms, and fall inspections ensure the roof is prepared for cold weather and snow loads. Additional inspections should be performed after major weather events such as hailstorms, high winds, or heavy snow. Many roofing warranties require biannual inspections to maintain coverage.
A professional commercial roof inspection typically costs between $300 and $1,500 depending on the roof size, complexity, and the level of detail required. Basic visual inspections fall at the lower end, while comprehensive inspections that include infrared moisture scanning, core sampling, or electronic leak detection cost more. Many commercial roofing contractors offer free inspections as part of their service or maintenance programs, particularly if they are being considered for repair or replacement work.
Building maintenance staff can perform basic visual checks between professional inspections, such as clearing drains after storms and reporting visible damage. However, comprehensive roof inspections should be conducted by qualified roofing professionals who understand the technical details of commercial roofing systems, can identify subtle signs of deterioration, and have the training and equipment to safely access and traverse the roof. Professional inspectors can also identify issues that untrained eyes would miss.
When problems are found during a commercial roof inspection, the inspector will document the issues with photographs and descriptions and provide recommendations ranging from immediate repair to monitoring. Critical issues like active leaks or structural concerns should be addressed immediately. Minor issues may be scheduled for the next maintenance cycle. The inspection report serves as a roadmap for prioritizing repairs and budgeting for future work. It also provides documentation for warranty claims and insurance purposes.