Direct Answer
Infrared and thermal roof scans can identify thermal anomalies that may indicate concealed moisture, wet insulation, missing insulation, air leakage, thermal bridging, delamination or other differences in how portions of a roof assembly absorb and release heat. They are particularly useful for surveying large low-slope commercial roofs and locating areas that deserve physical verification.
The critical limitation is that an infrared camera does not directly see moisture, insulation, leaks or concealed roof conditions. It measures infrared radiation from the surface and displays apparent temperature patterns. A thermal anomaly can have several possible causes, so suspected wet areas should be verified using direct inspection, moisture meters, core cuts, test cuts or another appropriate method. ASTM C1153-23 specifically states that infrared imaging can locate wet insulation but does not determine the cause of moisture or its point of entry. :contentReference[oaicite:0]{index=0}
ASTM E3216-26 likewise describes infrared thermography as a diagnostic tool that can survey large areas efficiently, while recommending direct measurement techniques at representative locations to confirm conclusions drawn from thermal anomalies. :contentReference[oaicite:1]{index=1}
Who This Applies To
- Commercial property owners and asset managers
- Facility and property managers
- Commercial real estate buyers and investors
- Roof consultants and building-envelope professionals
- Owners’ representatives and developers
- Property-condition assessment teams
- Owners planning roof replacement or restoration
- Building owners investigating recurring roof problems
Not for: Infrared scanning should not be treated as an X-ray of the roof or as a stand-alone diagnosis. The usefulness of the scan depends on roof construction, weather, surface conditions, equipment, timing, operator experience and verification of the thermal findings.
1. What an Infrared Roof Scan Actually Measures
An infrared camera detects infrared radiation associated with the surface of the roof and converts the detected radiation into a thermal image.
The image can reveal areas that are behaving thermally differently from surrounding portions of the roof.
Those differences can sometimes be associated with:
- Moisture retained within roof insulation
- Wet substrate materials
- Missing or displaced insulation
- Thermal bridging
- Air leakage
- Delamination
- Differences in roof construction
- Other sources of abnormal heat transfer
IIBEC specifically emphasizes that the camera detects thermal patterns rather than directly detecting moisture. :contentReference[oaicite:2]{index=2}
2. What Thermal Scans Can Show About Concealed Moisture
The most common commercial roofing application is locating areas that may contain concealed moisture within the roof assembly.
Under suitable conditions, wet insulation or substrate can behave differently from surrounding dry material because it stores and releases heat differently.
During nighttime surveys, for example, portions of a roof containing retained moisture can remain warmer than surrounding dry areas after the roof surface begins cooling. This can produce a thermal pattern that helps the investigator map suspected wet areas. IIBEC describes this principle as a primary application of infrared roof moisture surveys. :contentReference[oaicite:3]{index=3}
The scan can therefore help answer:
- Where are suspected wet areas?
- How extensive do the thermal anomalies appear to be?
- Are anomalies isolated or widespread?
- Which areas should receive physical verification?
3. It Can Help Map Suspected Wet Insulation
Infrared scanning can be particularly useful when an owner needs to understand whether concealed moisture is localized or distributed across a large roof.
For example, a scan may identify:
- A concentrated thermal anomaly around a penetration
- A larger irregular area of suspected wet insulation
- Multiple isolated anomalies
- A broad area requiring additional investigation
ASTM C1153-23 is specifically titled Standard Practice for Location of Wet Insulation in Roofing Systems Using Infrared Imaging and establishes conditions and procedures for using infrared imaging for this purpose. :contentReference[oaicite:4]{index=4}
4. It Can Help Identify Missing or Discontinuous Insulation
Not every thermal anomaly represents moisture.
Differences in insulation thickness, missing insulation, different insulation materials or discontinuities within the assembly can also create thermal patterns.
IIBEC has documented cases where gaps or damaged insulation boards produced thermal images resembling those associated with wet insulation. Physical verification was necessary to determine the actual cause. :contentReference[oaicite:5]{index=5}
This is why a thermal image should be interpreted as evidence requiring investigation, rather than as the final diagnosis.
5. It Can Reveal Other Thermal Anomalies
Depending on the building and assignment, infrared thermography can also help identify thermal patterns associated with:
- Air leakage
- Thermal bridging
- Missing insulation
- Delamination
- Heat loss
- Differences in construction
IIBEC describes thermography as a non-invasive diagnostic method for identifying thermal patterns that may indicate air leakage, thermal bridging or concealed moisture. :contentReference[oaicite:6]{index=6}
6. It Can Survey Large Roof Areas Efficiently
One of the major advantages of infrared scanning is coverage.
A large commercial roof can contain thousands or hundreds of thousands of square feet that would be difficult to investigate through destructive testing alone.
Thermal scanning can help narrow the investigation to specific areas before the owner spends money on intrusive testing.
ASTM E3216-26 specifically recognizes the ability of infrared thermography to survey large areas in a relatively short period. :contentReference[oaicite:7]{index=7}
7. It Can Help Define Areas for Core Cuts or Test Cuts
A thermal scan becomes substantially more useful when its findings are physically verified.
A typical investigation can follow this sequence:
- Perform the thermal survey under suitable conditions.
- Map thermal anomalies.
- Select representative locations for verification.
- Use direct moisture measurement, core cuts or another appropriate investigation method.
- Compare the physical findings with the thermal images.
- Refine the moisture map if necessary.
ASTM C1153-23 explicitly includes verification of infrared data using invasive test methods. :contentReference[oaicite:8]{index=8}
8. What Infrared Cannot Tell You: The Exact Source of Water
An infrared scan does not tell you where the water entered the roof.
A thermal anomaly may identify an area where moisture is retained, but it does not automatically identify the failed seam, flashing, penetration, drain or other pathway that allowed water into the assembly.
ASTM C1153-23 specifically states that the practice does not provide methods for determining the cause of moisture or its point of entry. :contentReference[oaicite:9]{index=9}
That distinction is critical:
Moisture location ≠ leak source.
9. It Cannot Directly See Through the Roof
The camera does not literally see through the membrane and insulation.
IIBEC explains that infrared cameras detect radiation at the surface closest to the camera; they do not directly see concealed layers. Investigators interpret surface thermal patterns to infer what may be happening within the assembly. :contentReference[oaicite:10]{index=10}
Therefore, a thermal image is an indirect diagnostic indication, not a direct photograph of the roof’s interior.
10. It Cannot Confirm Every Thermal Anomaly Is Moisture
This is one of the most important limitations.
Thermal differences can result from:
- Different insulation materials
- Different insulation thicknesses
- Roof construction changes
- Missing insulation
- Reflective surfaces
- Roof patches
- Ballast or gravel
- Heat-producing equipment
- Air movement
- Stains or surface differences
- Ponding water
- Environmental conditions
IIBEC documents numerous examples of false or ambiguous thermal signatures caused by roof construction and surface conditions. :contentReference[oaicite:11]{index=11}
11. Roof Surface Conditions Can Affect the Results
The roof must be suitable for thermal imaging.
Potentially difficult conditions include:
- Standing water
- Wet roof surfaces
- Heavy gravel or ballast
- Highly reflective surfaces
- Complex rooftop equipment
- Different roof materials
- Heavy debris
- Vegetation
- Heat discharged onto the roof
IIBEC notes that reflective surfaces, heavy ballast, ponding, heat-producing equipment and other conditions can interfere with thermal interpretation. :contentReference[oaicite:12]{index=12}
12. Weather and Timing Matter
Thermal scanning depends heavily on environmental conditions.
For low-slope roofs, suitable conditions commonly involve sufficient solar loading during the day followed by appropriate nighttime conditions so differences in heat retention can develop.
ASTM C1153-23 addresses meteorological conditions as part of the practice, and IIBEC identifies factors such as sunshine, wind, surface moisture and temperature differences as important to obtaining useful results. :contentReference[oaicite:13]{index=13}
A scan performed under unsuitable conditions can produce weak or ambiguous thermal patterns.
13. It May Not Work Equally Well on Every Roof System
Roof construction matters.
Different combinations of:
- Membranes
- Insulation
- Cover boards
- Decks
- Ballast
- Surfacing
- Attachment methods
can produce very different thermal responses.
IIBEC notes that different roof systems have different thermal characteristics and that some roofs may not be successfully surveyed using infrared under certain conditions. :contentReference[oaicite:14]{index=14}
14. Gravel-Surfaced Roofs Can Be More Difficult
Gravel-surfaced built-up roofs can create particularly complicated thermal patterns.
Variations in gravel and bituminous surfacing can create apparent thermal differences that make it more difficult to distinguish actual moisture-related anomalies from other patterns. IIBEC has specifically identified gravel-surfaced built-up roofs as challenging environments for accurate thermal interpretation. :contentReference[oaicite:15]{index=15}
15. Rooftop Equipment Can Create False or Competing Signals
Large commercial roofs often contain:
- HVAC equipment
- Exhaust systems
- Fans
- Electrical equipment
- Solar arrays
- Pipes and conduits
These components can produce or alter thermal patterns.
Heat discharged from equipment, for example, can create an apparent anomaly that has nothing to do with wet insulation. IIBEC identifies heat-producing equipment and air discharge as potential sources of misleading thermal signatures. :contentReference[oaicite:16]{index=16}
16. It Does Not Replace a Physical Roof Inspection
A thermal survey should generally supplement, not replace, a physical roof assessment.
A physical inspection can identify conditions that may not produce a useful thermal signature, including:
- Open seams
- Surface cuts
- Mechanical damage
- Deteriorated flashings
- Loose edge metal
- Damaged penetrations
- Blocked drains
- Surface deterioration
IIBEC describes infrared as an investigative tool that provides additional information beyond what may be visible to the naked eye; it does not eliminate the need for roof access and physical verification. :contentReference[oaicite:17]{index=17}
17. It Does Not Automatically Determine Remaining Useful Life
A thermal scan can contribute evidence to a roof condition assessment, but the scan alone does not establish how many years a roof has left.
Remaining useful life depends on broader factors such as:
- Roof age
- Roof system
- Overall condition
- Moisture conditions
- Maintenance history
- Leak history
- Installation quality
- Environmental exposure
- Future use
Thermal findings can help determine whether concealed conditions should affect that assessment, but they are only one part of the overall evaluation.
18. It Does Not Automatically Tell You Whether to Replace the Roof
Finding thermal anomalies does not automatically mean the entire roof requires replacement.
The findings may instead lead to:
- Localized repair
- Moisture verification
- Removal of wet insulation
- Restoration
- Recover evaluation
- Further investigation
- Full replacement evaluation
The appropriate response depends on the extent, location and significance of the verified condition and the overall roof system.
19. How the Results Should Be Reported
A useful thermal roof report should make it possible to connect the thermal findings to the physical roof.
Depending on the assignment, documentation may include:
| Information | Purpose |
|---|---|
| Thermal images | Show detected thermal patterns. |
| Corresponding visual photographs | Show the physical roof condition. |
| Roof plan | Locate anomalies. |
| Anomaly boundaries | Estimate the affected area. |
| Verification points | Document physical testing. |
| Moisture findings | Confirm or reject suspected moisture. |
| Limitations | Explain conditions affecting interpretation. |
| Recommendations | Identify appropriate next steps. |
20. A Practical Thermal Roof Investigation Sequence
- Review the roof system. Understand construction, insulation, membrane, deck and previous repairs.
- Review the roof history. Identify leaks, maintenance and previous moisture investigations.
- Confirm suitability. Determine whether weather, surface and roof conditions are appropriate for thermal scanning.
- Perform the thermal survey. Capture thermal imagery and corresponding roof information.
- Map thermal anomalies. Identify areas requiring further investigation.
- Perform a physical roof inspection. Compare thermal findings with visible conditions.
- Verify representative anomalies. Use direct moisture measurement, core cuts or other appropriate methods.
- Distinguish moisture from other causes. Consider insulation differences, equipment heat, roof construction and environmental factors.
- Document confirmed conditions. Map verified wet areas separately from unverified thermal anomalies.
- Integrate the results. Use the findings with the broader roof condition assessment.
- Develop recommendations. Determine whether repair, restoration, monitoring, further testing or replacement evaluation is appropriate.
Bottom Line
Infrared roof scans are best understood as a way to map thermal anomalies that may reveal concealed conditions, especially areas of potentially wet insulation. They can survey large commercial roofs efficiently and help focus physical investigation where it is most needed. ASTM C1153-23 specifically recognizes infrared imaging for locating wet insulation in roofing systems. :contentReference[oaicite:18]{index=18}
But thermal imaging is not a moisture detector, leak locator or roof-condition crystal ball. It cannot directly see through the roof, determine the source of water, prove that every anomaly represents moisture, or independently establish whether a roof should be replaced. IIBEC and ASTM both emphasize interpretation, suitable conditions and physical verification of thermal findings. :contentReference[oaicite:19]{index=19}
The most defensible approach is therefore thermal scan + physical inspection + targeted verification. Used that way, infrared information can provide valuable evidence for roof condition assessment, moisture mapping, repair planning, due diligence and capital decisions without treating the thermal image as the diagnosis itself.
Related Questions
- When does a commercial roof moisture survey add value?
- How much roof moisture is too much?
- How is a commercial roof leak investigated to find the root cause?
- What is a commercial roof current condition inspection?
- What is a commercial roof condition report?
- When is roof core sampling appropriate during due diligence?
Sources
- ASTM C1153-23 – Standard Practice for Location of Wet Insulation in Roofing Systems Using Infrared Imaging
- ASTM E3216-26 – Standard Guide for Use of Infrared Thermography in Evaluation of Buildings, Building Systems, and Equipment
- IIBEC – Infrared Thermography: The Detective in Your Toolbox
- IIBEC – Infrared Thermography in Today’s Roofing World
- IIBEC – Roof Moisture Surveys: An Effective Tool for the Industry
Last reviewed
September 29, 2026
Related Resources
- When Does a Commercial Roof Moisture Survey Add Value?
- What Is a Deck Core Cut and What Does It Reveal?
- How Is a Commercial Roof Leak Investigated to Find the Root Cause?
- What Is a Commercial Roof Current Condition Inspection?
Need Commercial Roofing Help?
ShieldLine Roofing can help commercial property owners investigate suspected roof moisture, document roof conditions, identify areas requiring further testing and develop practical repair or maintenance recommendations.
Disclaimer: This information is for general educational purposes and does not replace a project-specific assessment by a qualified roofing consultant, infrared thermographer, engineer or roofing professional. Thermal imaging results depend on roof construction, environmental conditions, equipment, operator experience and verification methods. A thermal anomaly should not be treated as confirmed moisture without appropriate physical verification.
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