As part of my Level I, Infraspection had a flat roof inspection as a self directed assignment. Just got the opportunity to do a practice one last night and I am hooked. The roof was a spray foam application about 5 years old over a built up tar and gravel roof.
Near perfect conditions: Rain all last week, 3-4 days of drying out, the surface was 99% dry(two wet piles of leaf debris), sunny all day with 80F and a temperate night of 70F.
The water beneath the surface popped out like a burner on a range. I was able to confirm the moisture with a moisture meter.
A few questions for guys who are veterans at these inspections(I know some of the questions go beyond the SOP for these inspections, I’m just trying to understand it). Some of the images show large areas of moisture beneath the surface.
What would cause this? Infraspection mentioned water can remain trapped in insulation for decades. Could this be moisture trapped between the old tar and gravel roof and the insulation from before the foam was applied?
Could this be due to an improper application or mix of the material? The wet areas all stem from low spots in the roof, as if the puddles were soaking through the surface as they sat after a rain.
Would this amount of moisture necessitate a tear off, drying and new roof?
Roof surveys can be loads of fun. Careful with SPF roofs as exposed foam (areas where elastomeric coating has worn off) can mimic trapped moisture. Same goes for BUR if gravel worn off.
Glad you verified with a moisture meter.
Congrats on getting into real IR work. Roof scans are good for finding small areas of latent moisture in the roof system so they can be repaired while not having to replace the whole roof. That scan shows the whole roof is affected and should be stripped down to the substrate. Good Job
Arnie the level ll is the meat in the meat and potatoes it teaches in depth thermal imaging it is the thermal of thermography. My learning curve has been stretched pretty flat with age but I found level ll very interesting and easy to understand. If one is to progress above finding missing insulation in a ceiling or a wet spot in a wall. Level ll is a must into the electrical arena where you are dealing with strictly temps.
My IR business never really progressed much until reaching level ll
I took my level l and level ll with Flir ITC and my level lll with Infraspection both are great learning facilities. My personal choice is infraspection
It’s an E50bx. Those are screen captures off of FlirTools.
(Jim Seffrin, Director of Infrared Training)
Congratulations on completing your first roof inspection! As a professional thermographer, this application continues to be one of my favorites to perform. The following are in response to your questions above.
Q: What would cause this? Infraspection mentioned water can remain trapped in insulation for decades. Could this be moisture trapped between the old tar and gravel roof and the insulation from before the foam was applied?
A: As you correctly state, water in roof insulation can remain trapped for decades. For spray applied polyurethane roofs installed over a gravel built-up roof, water that enters the new system can collect either in the new foam or in between the existing and new systems. If the SPUF was not fully adhered to a clean substrate or if gravel is left on the BUR membrane, water can migrate laterally in a very short period of time.
Q: Could this be due to an improper application or mix of the material? The wet areas all stem from low spots in the roof, as if the puddles were soaking through the surface as they sat after a rain.
A: Yes or it could be that water has entered the new system and collected in the low spots that you describe. It is also possible that water present in the old BUR has found its way into the new system. Depending upon the thickness of the SPUF, it is possible that some of the warm areas are caused by moisture that was present in the old BUR when the SPUF was applied.
Q: Would this amount of moisture necessitate a tear off, drying and new roof?
A: If the majority of the roof contains subsurface moisture, the most practical course of action will likely be the removal of all roofing materials and insulation down to the deck, repairing deck damage as required, and installing a new roofing system appropriate for the subject building. An infrared inspection of the new roof should be performed as a Q/A measure within 3 to 6 months after installation has been completed. IR inspections should be performed annually thereafter and appropriate maintenance performed.
Lastly, the thermal patterns seen in your images serve to contradict claims that SPUF does not absorb water.
Keep up the good work!
(Jim Seffrin, Director of Infrared Training)