Radiant Floor/ Flat roof question

Hello all, Been doin the thermal imaging thing for just about a month now just figuring things out. Did the Level I thing and all that, but I have a possible radiant floor gig next week as well as a flat roof survey. As far as the radiant floor inspection goes, owner thinks there could be a leak. Can anyone recommend methods that will help with my images? I assume it would be best to cool the floor then re heat, Would that be correct? Also I have a possible roof survey. I know it’s best to do in the evening and to bring someone else along, but any other info or advice on these areas would be highly appreciated. Thanks, Tim Halpin-Pacific Inspection Services

Tim - We do not have many radiant floors here, but I would be very interested in hearing from you as to how your inspection came out. The leak problem, if there is one, could be a stickler and let me (us) know if you figured out a way to demonstrate it. Thanks!

Having them turn off the heat a couple of hours before the inspection might work, then turning it up high later to try to gather a larger heat signature. Doesn’t radiant flooring have a concrete layer, and is that hard to navigate definitively with IR? Thanks…

This is a hot water line from a kitchen sink to the hot water heater. I found the leak was in the wall just out of the concrete. Camera 160X120 FLIR B2.
At the time i did not have a wide angle lens.




You need the heat turned off yesterday.

Run the a/c till you can hang meat.

Scan the floor before you do anything with the heat. If there is a leak, evaporative cooling may show a cold spot at the leak.

Set up your stuff, turn on the heat and watch it appear.

Depending on the size of the leak, it can be masked when the heat spreads throughout the floor, so you should be there constantly scanning. The greater the delta t the more you will see as it heats up.

Why does the client think there is a leak?
Get this information first.
Do they know where it may be leaking and how much is leaking?
Can the system be pressure tested first to see if there is in fact a leak that you need to find?
Don’t depend solely on the IR to find everything out. Do your homework.

Hey guys thanks for the input. This guy suspected that there might be a leak, but there were other issues he had to address first and I did not here back from him. I did however get to scan a floor that had radiant heat (pex lines in a slab) and laminate wood flooring over it. The heat was on for a few hours , but the entire slab had not heated up and I could make out where the lines were, pretty neat. Sorry I don’t have the pictures, I will post them in the future. The AC idea sounds great, but they are not used in these parts so much. Thanks again for the input.

Dear Tim:

Several tips on infrared inspection of flat roofs may be found at our content-based website, IRINFO.ORG.

Of particular interest is a Tip from April 2002 titled, ‘Infrared Inspections of Flat Roofs.’ Subject URL is:


Another resource that you may wish to consult is the Infraspection Institute Standard for Infrared Inspection of Insulated Roofs. This comprehensive document is intended for those who specify infrared inspections as well as thermographers who perform inspections. This 11 page document outlines specific inspection procedures, safety concerns, confirmation of data, and required report content.

Copies of the standard may be obtained by calling 609-239-4788 or visiting the standards section of the Infraspection Online Store.

Hope this is helpful.

Jim Seffrin
Infraspection Institute


IR Training from the IR Professionals



If you have not yet done the floor, I too suggest you start with the system off or on no circulation. Typically the thermal signature will become obvious after 20-40 minutes. You must use the narrowest span setting you can set on your camera and then adjust the level until you can locate the center of each run.

Regarding roofs, they can either be quite simple or very complicated. Built up roofs are the ones you’d like to tackle first! Single-ply roofs are typically more difficult.

We have several paid webinars ($79) available that would get you started on either type of roof. I’m not trying to hawk anything there, but, honestly, viewing these would probably be a lot cheaper than going up on the roof with the wrong conditions. You can find details at:


Please also be aware that roof work is very dangerous. NOT that you will fall over the edge, but there are many obstacles and danger points on a roof and, curiously, you will be virtually night blind when you have your IR camera turned on! We cover many of these issues in the webinar as well.

Thermally yours,

John Snell
ASNT NDT Thermal/Infrared Level III #48166
Snell Infrared





I have taken both Level I and II with Infraspection. In addition, I attended the Flat roof webinar John is referring to in the above post. Excellent courses!!

I particularly liked the webinar. It was too the point and very informative. Worth every penny :slight_smile:


Radiant floors show up pretty good if you start cold, and let the system run as you scan.