Tell Me What You See!

The house is 30 yrs old and has hard coat conventional stucco on all 4 sides.

The buyers had a home inspection prior to your inspection. Their inspector was on the roof and told them the house had no kickout flashings at 5-6 areas, and improper flashings at several other areas. Several signs present of prior drywall patches and some moisture stains at ceilings or walls.

Your lady buyer is concerned about this + maybe mold in the walls. So she orders moisture probing of stucco outside and Infrared testing inside.

Before your inspection you get 10" of snow and temps in the 20’s, and it will be that way for say several weeks. The roof is totally snow covered and you can’t see flashings OR do the stucco moisture testing, only the IR.

Look at the following Pics and tell us what you think. Hint … Both IR shots are at the 2nd floor of house. The 1st 2 Pics are in a bedroom on outside wall adjacent to a gable where the home inspector said a kickout flashing was missing at the sloped composition roofing.

The 2nd 2 Pics are in a large bathroom with a metal barrel roll roof over it and are adjacent to where the rolled barrel roof meets the sloped comp roof and home inspector said it had a flat metal flashing rusting and sloped back to the interior of the house walls.

??? Moisture / Air Leakage / Bad Insulation ??? You can’t see the roof, flashings, etc … So play with it.





Same house as in the 1st Post.

1st 2 Pics are of a 2nd floor tiled shower. Signs of drywall repair at ceiling below this. The tile at the drain is cracked and patched with plain caulking. The home is vacant and shower has not been used since owners moved 1 week ago.

2nd 2 Pics are of ceiling below shower.

??? Wet / Dry ???





In all of the photos I see areas that are cooler than their surroundings. It’s hard to say just how much cooler for lack of spot readings at the cool spots and the warmer areas nearby.

The isolated cool patch outside the shower makes me wonder if there had been a bathmat laying on that area before the photo was taken.

Were moisture levels in these areas measured? If so, what were the results of those tests?

William …

I’m gonna give them a few days for peoples thoughts then I’ll post again. The 1 temp at upper left of the IR Pics is at the spot bullseye


Perhaps I should have read between the lines better and instead of telling you what I see (which is what the title of your post asked for), told you what I think might be going on.

I know how the spot function works, but thanks for that bit of clarification. Knowing what the temperatures of the areas near them would have been nice, but no more conclusive in any case, so never mind.

As you allude to in your post, cooler areas could be caused by any number of things including moisture, air leakage, and bad insulation. So, the logical approach would be to employ a process of elimination.

Taking them one at a time:

Moisture - Since we have no moisture meter readings to help us (correct?), we are left to look for visual clues like discoloration. In the first pair of photos, it is impossible to tell whether there is any due to uneven lighting. In the second set, there appears to be some slight discoloration, but it is not consistent with other moisture stains I have seen, and is well above the coolest area in the IR photo. In the third set, I see no discoloration. In the fourth set, I can see a slightly cooler area that coincides with the ceiling repair, but it’s pretty amorphous. I would say of all of the images, that one would be least likely to be associated with moisture, but that is just a guess.

Air leakage - With the first two sets of photos, we cannot eliminate air leakage, because either the areas behind these walls were inaccessible thus un-inspected, or they were inspected and that information is being withheld to test our deductive reasoning capabilities. In the third and fourth sets, these areas are not near exterior walls, and I see no trail leading to them, so I’m thinking not.

Bad insulation - It’s a very sad thing when Good Insulation goes Bad, thus tempting to lay blame at its door (or wall or ceiling or whatever). However, of the three suspects, this is the least likely. Thermal patterns I have seen from missing or sparse insulation tend to run joist-to-joist or stud-to-stud, giving sharp, straight-edged patterns where the structural members are and less-well-defined edges between them. Not seeing that here. Space between first and second floors are not typically insulated, so unlikely to be the culprit in the third and fourth sets of photos.


Moisture - Possible (given the information provided) in all three locations depicted.
Air Leakage - Possible in the first two locations. If you put a gun to my head and said “guess”, this is what I would guess, but not so much in the third location. That would be “Moisture”
Bad Insulation - Possible in the first two locations, but not as likely as our other choices, and highly unlikely in the third location since there would be no insulation there to go bad.

It will be interesting to see what others have to say.

What device are you using Dan?

Looks like an E8.

Like Dominic guessed … Flir E8

William … In the 4th Set of Pics there is a bathroom above it with signs of homeowner type repaired tiles.

I like the one of the cool tile outside the shower where you pulled the wet shower mat back to take the image (they have a tendency to get wet when someone steps out of the shower). It’s reminiscent of Condom Bob’s “leaking shower gasket”.

Personally, I wouldn’t be trying to draw conclusions from any of those images other than to say some areas are emitting less infrared radiation than others and if the inspector suspects that they may be related to moisture, should be testing using a more definitive method…

Chuck made a good point …

There was a bath mat there that I turned up. There was signs of prior moisture stains and patching at the living room ceiling below this area??

The tile at the bath drain is cracked and patched with plain caulking. The home is vacant and I’m told the shower has not been used since owners moved 1 week ago ???

Maybe they have squatters because you can see the wet mat at the bottom right corner of the image.

Your observation of the ceiling and description of the history serve to highlight that infrared is not a stand-alone, point and shoot building diagnostic tool (that’s why it’s so hard to accurately analyze someone else’s images captured under unknown conditions). To use IR imaging effectively, the operator needs to be observant with his own eyes, understand areas which are most likely to exhibit thermal exceptions and what characteristics the thermal patterns different types of exceptions display. It’s also important to control the environment to increase the likelihood of finding exceptions. I would have run quite a bit of water and manipulated the interior temperature hours before I broke out the imager to look for exceptions.

No the mat that was pulled back did not have to be wet to leave the pattern that was shown. I see that all the time when I check shower pans. Simply put the floor beneath the mat was protected from the same temp that the rest of the floor was exposed to.

Another example of this is when there is a closet door that is partially open toward the wall before a image is taken you can see two different temp patterns up on closing the door. Basic stuff;-)

Yes, I understood that, thanks. I rated Air Leakage and Bad Insulation as least likely in that area, but would not conclude that that signature indicated a leak from overhead in the absence of moisture meter readings supporting that hyphothesis.

I guess you missed my comment in my first response: “The isolated cool patch outside the shower makes me wonder if there had been a bathmat laying on that area before the photo was taken.”

Chuck and Charley have eloquently stated the problems that I alluded to in my initial response. Infrared images by themselves are seldom sufficient to draw any actionable conclusions, but as a Level I thermographer, I am sure you are aware of this. Perhaps that was the point of this exercise?

I ran into this problem a few weeks back when I saw a stray warm spot in a downstairs bathroom ceiling. Air leakage from the nearby vent fan, electrical wire in contact with the drywall, and warm water leaking from upstairs plumbing were all suspects, but moisture levels were even and my inductive current detector offered no additional information. I explained to my client why I was unable to draw any helpful conclusions, but he thanked me for telling him about it just the same.

William, I think you made a great assessment with the available information provided, which is insufficient to make a determination of anything one way or the other. I especially like your statement “So, the logical approach would be to employ a process of elimination.”! We should spend more time on “what it is not” than “what it seems to be”.

ie. there is information about flashing and roof issues that were not addressed because of existing weather conditions. Is there not access to the underside of the roof in these locations?

I see discoloration in the digital pics: however, this does not verify actual roof/flashing leakage.

  1. We are looking at scans in a room that frequently experiences 100% rh during use. Any slight heat loss in the building envelope will result in condensation.

  2. Cooler Sheetrock promotes condensation of water vapor. So what is causing cooler temps? Well we must consider the three methods of heat transfer; conduction, convection and radiation. As the top of the ceiling or walls are not exposed to the sky, we can “eliminate” radiational cooling. Will a lack of proper insulation allow air movement and subsequent heat loss. Yes it would, but we may not be able to assess this visually without invasive inspection. Does the density of materials use to construct this building envelope cause some areas to conduct heat at different rates?

There are two other considerations. Can we use our IR Building Science training to determine “Apparent R-Value” of the cooler spots of the wall/ceilings? Or we can just assume that there is no insulation there based on the knowledge of construction practices were insulation is not used in particular areas. Second, we can use psychometrics to determine what temperature we should be expecting from wet evaporating objects subject to the ambient air. For example if the thermal exception is colder than the calculated wet bulb temperature, we are not looking at just evaporative cooling. This leads to the possibility that this is not a roof leak. We can not exclude this from being water, but that it could be water due to adverse conditions such as air leakage and/or inadequate insulation.

My next step would be to apply a convective heat source to the anomaly and record the reaction. This is the the only method to detect moisture over air leakage and insulation issues.

  1. Thermal assessment: how do the thermal anomalies represent the occurring heat transfer? There are numerous targets in each thermal scan. How do each of these target areas represent the heat transfer? Did you tune your scans for each and every target represented in the scan? If not, the Delta T data will be significantly in error.

Without accessing the raw data in these scans, and reliant on the limited data provided, I can eliminate 99% of the thermal exceptions based on what I know about how buildings are constructed in my area, and how they fail to function as intended. I would conclude that “if” this were a moisture issue (Leakage), it could be a condition where past leakage had occurred but has significantly evaporated over a substantial period of time. My next act would be to cause the leak to occur and document it as it happened.

  1. “If” what I see in digital pics is in fact water staining, taking moisture meter readings is insignificant information. Sticking the wall/ceiling with a moisture meter may or may not record moisture. Thermal scans indicate that if this is moisture, it is an inndiract measurement of conditions deep inside the wall (likely beyond the functional ability of a commonly used moisture meter). Either way, the information is irrelevant because the current condition depicted by IR indicates evaporated moisture (if anything). You will not get usable data using a moisture meter in this state.

If you don’t go find more data, this inspection is inconclusive as to the “source” of this condition. Even if you can say it’s wet, you can not determine the source of why it is wet. Subsequently you can not fix the problem. This leads to the people that call me and tell me they have spent thousands to fix the problem, but it’s still there and they have no idea what to do about it.

All points well taken, and my thoughts were inconclusive without further testing or evaluation. Which in some locations is not possible due to weather or areas with no access … AND if buyer is not willing to spend more $$$$$ OR seller will not give them more time extension. There it is …

I think this raises a question we as inspectors need to consider: Is it unprofessional to be reporting on conditions we find if we cannot offer some convincing explanation that might indicate an actual problem?

My inspection today presents a perfect example. Take a look at the two attached IR images.

These photos are from either side of a wall dividing a first floor shower stall from its adjacent bedroom. Obviously something is warming up the ceiling in this area, but what?

It could not be warm water, since the water heaters were not lit at the time the photo was taken. I seriously doubt it was wiring, as the lighting in the house was LED, which draws very little current.

This was new construction, and the kitchen appliances were not installed, thus could not be drawing current.

I had been running the furnace for a while before capturing these images, so I shut off the furnace and went about inspecting the rest of the property. I came back about an hour and a half later and the warm spots were gone. At that point I felt a reasonable guess would be that there was a leaking air duct in the area, but I would have to have removed sheathing in the attic to visualize the area, so I could not confirm it.

In this case, I feel I was able to eliminate enough other possibilities to form a plausible hypothesis (leaking ductwork), so I included it in my report.

A few weeks back, though, I found a warm spot that I could find no plausible explanation for. I did not include mention of it in my report, but did discuss it with the buyer.

What say the rest of you? Do you report an anomaly even if you can’t offer a plausible explanation?



That is where the duct is in contact with the sheetrock on the ceiling. When you run the A/C it will be cold. You will often find that in transitions to/from a ceiling area where there is minimal space between the ceiling and the roof (like at the transition from an attic space over a first-floor area up to the upper attic).

I do not report these unless we have dewpoint issues.

I know that the above did not answer the broader question that you posed to us. My approach is to perform enough deductive analysis, observation and testing in order to develop at least a likely theory as to the source of the anomaly, which depending on the condition may or may not be comment worthy. I figure that’s what people are paying me for and I do, in fact, charge a fee for performing infrared thermography at an inspection. I cannot even think of the last time I reported an unknown anomaly, if ever. If I as the thermographer who can see the anomaly can’t figure it out, what is a contractor who doesn’t have my equipment going to come up with? Reporting phantom anomalies for someone who can’t see them to try to investigate would simply create a frustrating exercise for both the buyer and seller. You can’t just hand-off undefined thermography exceptions for someone else to figure out.


All too many camera owners pull out equipment (like a thermal camera) in a Home Inspection, see something and then fall back on “This is a general inspection outside the scope of a Home Inspection”. When you pull out more than a flashlight, you have given up the right to fall back on “This is just a Home Inspection”.

As you have eliminated several options, what you have left is sufficient cause for an existing problem that warrants mention. You just didn’t point out a hot spot.

As Chuck pointed out, the A/C would make the same spot cold. If weather permitting, I switch between Heat and A/C. Personally I can run the A/C at any temperature, but others must be conservative here. This confirms leakage based on how fast, and where things change to cold.

Also he noted “I do not report these unless we have dewpoint issues”. Do not forget that we see this in winter as hot. If your in Texas, this will be a dewpoint issue come summer.

Also I note that the hot anomaly extends further away from the hotest spot in several locations. Based upon how long the heat was on, this shows the extent and rate of heat transfer within the building envelope.

Because this is a bathroom where hot water usage is a primary activity, this would elevate my concern about this condition.

We should never just refer this to someone else, except another thermographer because they do not have the ability to replicate what we have done.

Based on the OP, I do not run into the problem of finding something that the client does not have the money to verify the real problem. That in of itself eliminates inclusion in a report. I tell the client that there are particular issues that indicate a problem to me but additional fees will be required to verify. There were roof and flashing concerns, but conditions were not present to complete this inspection at this time. They can just have a roofer to poke around, or I can come back on another inspection and determine the specific repairs needed if there are any.