Moisture issues are one of the main reasons that roof integrity becomes compromised, and it is also one of the hardest problems to catch in advance. Thermography is one of the tools we use to find soiled insulation trapped inside a roof assembly. In many cases, roofs that are being attacked by moisture retain their structure and functionality, showing almost no signs of issues until it’s too late. Luckily, this building owner took proactive measures, and the issues found through the infrared scan were repaired efficiently before it became a big, and expensive, problem. 

The Specs: 

Type of Project: Inspection and Repair
Total flat roof area: Approximately 70,000 square feet

South Roof Section

Deck Type: Steel 
Vapour retardant: Reinforced kraft paper with adhesive
Insulation: 1.5” ISO insulation

Overlay insulation: 0.5” Fibreboard insulation

Roof Membrane: 4 ply built-up asphalt and embedded gravel roof membrane.

North Roof Section

Deck Type: Steel 
Vapour retardant: None
Insulation: 1.5” Fiberglass insulation

Bottom Layer of Roof Membrane: 4 ply built-up asphalt and embedded gravel roof membrane

Overlay insulation: 0.5” Fibreboard insulation

Top Layer of Roof Membrane: 4 ply built-up asphalt and gravel roof membrane 

The Ask: 

Our client requested a thermal scan for the roof to identify areas of suspect saturated insulation. There were no active leaks at the time of the thermal inspection, however, we wanted to ensure that there were no areas of concern. The roof has been properly maintained through the years with an annual roof inspection done in each of the past few years.  All roof leaks that have occurred were repaired on a timely basis.

This roof was replaced in stages, the north side in the early 1990s and the south side in 2001.  The estimated useful life of the roof systems on this building is typically 20 years.  We are past that timeline, especially on the north roof section, so the thinking was that a thermal scan would aid with diagnostic capabilities and perhaps indicate what additional lifespan can be expected.


The thermal scan identified two sections of saturated roof insulation on the north roof section and none on the south roof section.  The findings were then confirmed with a moisture probe. These areas were marked, and a proposal was submitted to the client with proposed repairs. Pictured below is an example of this kind of report. 

form detailing moisture damage in thermal scan


The damaged membrane and soiled insulation were cut out, and new insulation was installed at voids to match the existing thickness of the membranes to create an even seal without any slope differences in comparison to the rest of the roof. The damaged portions of the roof were disposed of.   We found that the areas of saturated insulation were slightly larger than the estimates provided in the thermography report.  We believe that thermography needs to be coupled with roof core test sampling to validate the full extent of the remedial repairs required.

Because of the thermal scan, the owners of this building were able to mitigate further damages.  If they had not completed these repairs then the area of saturated insulation would have continued to grow until it triggered an active leak at a roof penetration or at a breach in the bottom layer of roof membrane.  We were also able to provide some additional remaining useful life to the roof assembly as per the client’s direction.

Thermal roof scans are an important diagnostic tool to use in the maintenance of roof membranes, especially when there are roof overlays with multiple layers of membrane, making saturated insulation that is trapped in between roof layers impossible to see during routine maintenance. Combined with routine visual inspections, thermal scans on older roofs (over 10 years old) are essential for maintaining roof health and avoiding major issues. If you’re interested in finding more about our routine inspection offerings, click here, and find out why our clients rest easy knowing their roofs are functioning at peak performance. That’s the Elite advantage.