Well I am not a thermal-graphing certified inspector, but today I got a chance to try a infrared camera on a wall and ceiling (in different rooms). Here I got 2 pictures as below:
The picture A looks like this…it is above a window. My first thought was suspecting there might be a water penetration or leaking in attic, or from the roof, but my moisture disagreed that. Actually the dark area around the edge shows very low moisture level, so it couldn’t be water. I also went to the attic, checked from the hatch, couldn’t find any water stain as well. And, no sign of water stain can be observed on the ceiling.
So, my question is, what is it? Uneven insulation or even soffit vent air intake?
The picture B was from another room I got from a wall. It is vertical from ceiling to the bottom. Again no moisture can be detected in the dark area. The dark column looks like a stud behind the wall, and no such kind of bigger dark area at the bottom.
The picture B is actually vertical, the left side is ceiling and the right side is close to the floor.
Again, what it could be?
BTW I am from Canada, the outdoor temperature was 5 Celsius degree.
It is hard to know without seeing the areas around what you were shooting. Would the second photo be a hot water feed some place. The first does one does look like you were getting some thermal bridging, basically, cool air into the area.
Next, let’s get another thing straight. What is the difference between thermal bridging and thermal bypass?
Thermal bridging has to do with heat transfer through conductivity.
Thermal bypass has to do with heat transfer through convection.
You can look this up on the Internet, for the most part posted pictures are reasonably accurate (but not all).
As we are talking about “the attic” then we will assume we are talking about picture #1. This is not thermal bridging. Though the lack of insulation can cause increased thermal bridging. Missing insulation is not thermal bridging it’s thermal bypass.
I don’t know what you’re looking at in photograph #1 because thermal bridging has a geometric pattern which I don’t see here.
As for your comments about photograph #2, when would the hot water pipe register as a lower temperature on the scale rather than a higher one? As for thermal bridging, photograph #2 is in fact thermal bridging.
As for the original 0P:
These scans taken with a FLIR C2 are not radiometric so I was unable to analyze them further.
Arthur, your “first thought” was the correct thought. We are often told this when taking a test. Consider this in the future.
This brings up an interesting subject that I haven’t talked before in the past.
This is a prime example of not trusting the device you are using.
Why don’t you trust this device? Lack of education and experience with that device.
You trusted your moisture meter more than your thermal camera. You also trust your eyes more than your thermal camera.
As for your moisture meter, what makes that analysis a deciding factor? Do you know what a moisture meter actually does? It doesn’t measure moisture. The same is true with a thermal imager. It does not measure moisture. When you can perceive what each device is capable of and not capable of you will not so readily jump to conclusions.
Can you positively identify water with a thermal imaging camera? Yes you can. How? By understanding the laws of thermodynamics. That falls under the subject of education.
As for your choice of equipment; you have an 11°C temperature differential between inside and outside. This camera was not capable of picking up a thermal bridge in picture #1 and they are in fact there. You just can’t see them. This falls under the subject of equipment.
Back to picture #1: so if this scan is not thermal bridging, then it must be thermal bypass. Not necessarily so.
If you take John’s course which focuses heavily on identification of thermal patterns, you should readily identify this as a water leak.
Would I definitively call this a water leak in my report?
Based upon the limited information available concerning this situation, and by eliminating the other possibilities of what it “is not”, I would call this an apparent water leak. I would also include in my summary that limited visual inspection and inconclusive testing with electronic moisture testing equipment requires further evaluation beyond the scope of this home inspection. As the client does not own the property, the property owner must give consent for and is likely responsible for this further evaluation.
Please note that this situation would never arise during my evaluation because I would not have stopped where you stopped in collecting the initial information. This is not because you are lazy and didn’t try, it’s lack of experience and training. You are operating equipment in an inspection that you are not qualified to use or evaluate.
I highly recommend that you give your thermal imaging equipment credit for locating an exception that otherwise would go undetected as you experienced through your visual and moisture meter follow-up testing.
**" Actually the dark area around the edge shows very low moisture level, so it couldn’t be water. "
This is the most damaging statement you could make. It can be water (or water vapor), and it probably is. You just haven’t proven it yet.
Get training if you intend to offer thermography as part of a service or even use it as an unadvertised component of your inspections. Download a copy of this standard and read / follow it http://www.nachi.org/infrared-insp-bldg-envelope-sop.htm. It’s been provided to you free by Infraspection institute. You also need to make sure that your equipment is suitable for the task.
You need to be aware of the weather and building conditions at the time you are inspecting so that you have greater ability to interpret what you see. Your thermal imager “sees” incident infrared radiation, which it will interpret to temperature based on camera settings. What it displays as apparent temperature and renders as variations in surface temperature using a false color palette may or may not have any semblance of reality depending on camera settings, angle, geometry, material differences, emissivity and a host of other factors. You need to be able to discern what is contributing to and influencing the image that you see. Until you determine otherwise, what you are seeing is simply a pattern
Your targets in this case have a relatively high emissivity and are probably not greatly influenced by reflection. So the patterns are are probably indicative of actual temperature variations. Unexpected temperature variations are simply “thermal anomalies” until you can attribute them to a specific cause. Not every cold spot is indicative of moisture. Moisture will not show up as a cold spot on an infrared image under all conditions. Your moisture meter tests for moisture (i.e., it can provide definitive results when used properly), your thermal imager does not. Assuming that you have used your moisture meter appropriately, you have determined that the source of the thermal anomaly (singular because you have only found one anomaly - the ceiling / top plate) is not moisture related, so you must consider other alternative causes. Since the exterior temperature is substantially colder than the interior temperature (good job for including that essential information), it would lead us to determine the likely cause is air leakage or an insulation deficiency. If you took the time and care to place the house under some degree of negative pressure, an air leakage issue will typically have a distinctly different thermal pattern from an insulation deficiency, so you could more accurately report what you are observing. Keep in mind that just about all structures have some thermal deficiencies (no house is perfect). Not every minor deficiency warrants repair. IMO: In all likelihood, this area will not be visible or accessible from the attic near the eave and is probably not worth repairing, unless they are already doing insulation work in the home.
There are two possible sources for what you see in the wall corner (assuming it’s a corner). If it were an interior corner, we would attribute it to “corner effect”. It could also be due to thermal capacitance if the house has not reached thermal equilibrium. I suspect that this is an exterior wall corner. Think about how exterior wall corners are created using conventional framing methods. There is invariable a larger mass of lumber with a void between the studs that is inaccessible for insulating. Between the thermal bridging that occurs with the wood and the corner void (both typical), you have a very typical thermal pattern for the wall corner given the temperature conditions across the envelope. If you have the opportunity to take a similar image, under similar conditions, of an advanced framed structure, should should see a substantially different result in the corners. If the second image is not a corner is likely something in the wall, piping or multiple studs. Still not a concern.
From a reporting standpoint (based on the information provided), I would include the ceiling / top plate as a thermal envelope deficiency and not give the vertical observation a second thought.
Edit: I see that David has already responded in detail. As you can see from our responses, we can arrive at different opinions looking at second hand images and partial information. I can guarantee that had either of us been on site, we would have performed adequate secondary assessment to reach a similar conclusion. If I discount the moisture meter comment and go by thermal pattern alone, I would be inclined to think moisture. If it is, my meter would pick it up.
Note… the kind of moisture meter you have and how it is used it can make a difference.
Non-contact moisture meters can miss the moisture if the radio waves are going too deep and they miss the moisture close to the surface.
Pin contact moisture meters can miss moisture if it is too far below the surface (depending on how far you penetrate the pins).
I recommend a dual function moisture meter, such as the ‘survey master’.
Because your camera has poor resolution (no insult intended) then you may never see 50% of the available information that may be present and could be seen with a better camera (such as a FLIR e6 or above). Remember, your trying see defects that are many times below the surface of the materials and there are several methods to draw those images to the surface. Combined with these methods, along with a better IR camera, can make a 1000% difference in being able to gather real information or being blind and not knowing it.
Various patterns, temperatures, and how you verify defects is all part of the items you have to consider to report your observations. Drawing those images to the surface is a constant challenge. Under some conditions (with good delta T) this can be easy … and on some days it can be very hard. The knowledge of building science and the dynamic forces of energy movement and transfer is the other half, when trying to understand what the building is revealing when viewing it via and infrared camera.
I agree with missing insulation if this area was dry. We often see wind wash over top plates so outside information is important. Were there soffit vents in the area of picture one.
Picture two also looks like thermal bridging. Remember, not only are there studs in the corner (if it’s a corner) but usually there is a build up of joint compound in corner. If you look at other inside corners, wall and ceiling, you may see the same results.
When we were doing weatherization wind wash over top plates were the toughest to resolve and like Chuck said the ROI is probably not worth the effort.
Thanks everyone for great input. I personally prefer the 1st picture as lack of insulation, cold spot as well. I didn’t see any water stain in attic (from hatch) above the window. Anther thing is, if it is water accumulation along the edge (as per my understanding, the darkest area indicates the biggest temperature difference, or to say it as where the water might mainly stay at ), then the water should get the biggest chance to flow down to the wall, but I didn’t that vertical shadow image in the camera.