We have been asked what are the advantages of an aerial infrared roof survey over a direct IR scan from on top of the roof?

Can you detect problems from the air that you cannot detect directly from the roof?

Your input is appreciated.

Terry O

Terry,

I do not think that the detection is necessarily the point. If you have a lot of surface to scan aerial surveys can do the job in a very short period of time. and as long as the documentation on roof dimensions is correct, you are able to pick out the areas of concern quite readily, measure their location and then mark them in the day time.

The one time I was able to get an aerial survey, we shot the roofs of an entire facility with several million square feet of roof in two passes of a helicopter. We had initially decided to go with direct IR scan but ran into thermal problems because of our location. We essentially had less than an hour in the evening when we could accurately get any data. Don't remember the cost but it made the job doable and also provided information on a couple of roofs we would not have scanned due to safety concerns.

Ken Culverson

Aerial surveys certainly are quicker than walk-on scans. They also allow for a more perpendicular view of the subject, minimizing reflections that can make scanning rubber membranes tricky.

I've scanned dozens of roofs for customers from the air and I've almost never been disappointed with the results. I always, however, follow-up with a walk-on survey and use a moisture meter to "verify" the results whenever possible. I have on occasion found that depending on the membrane and the insulation, some anomalies turn out to be slightly larger when you get up close.

From my perspective as a service provider, the aerial survey is for the thermographer - to make sure I don't miss any spots. The walk-on survey is for the customer - they receive the data they need to make the repairs... the close-up IR and Visual photos, the anomalies outlined on the roof, verification, dimensions, etc., items you just can't get from the air.

Please feel free to check out my web site... It is full of images from aerial surveys and walk-on surveys.

Tom Kremser
www.AltheusIR.com

I have seen several aerial images however the problem will arrise when you have a roof with small wet areas that cannot be effectively scanned from the air. I recently scanned over one million sq ft of roof on one building(from roof top)to find over 80 wet areas mostly 1-2 feet in length to 20' by 6" wide from splits in the membrane these roofs where relatively new (5-11 yrs old) built up roof systems installed directly over iso with only one layer of insulation. The splits will continue until these roofs are replaced due to design. In the images of areial scans ive seen this would be near impossible to scan effectively. Having said all that I think you will quickly get the larger wet but may miss alot of the small ones plus if on the roof you have the opportunity to verify your findings while scanning which is critical for several reasons, establishing a base line of wet and dry, verifying large encrustations of asphalt, heat influence from roof top equipment, verifying retrofit roof sytems.... If your going to do this you have to be on the roof anyway. Both can be benificial depending on the scope of work and what you expect from your roof inspection.Hope this helps.

Craig