Vinyl Siding

This is the north side of a vinyl sided house last summer during the morning.
No heat or a/c running.

One section of siding is cooler than the rest.
Could not find anything visual.
There is a wood fabricated chimney to the right.
The interior of this area is a sheetrock living room wall.

Reflection? But it shows up in four pictures from different angles, even from up on the roof!

Any ideas?

I’d be tempted to get out my siding zip tool and check behind that piece. another possibility is that the drain holes in that piece are blocked or missing trapping moisture behind it. JMHO;-)

Is it condensation under the siding, being on the north wall it does not get direct sunlight during the day so it never fully dries out.

Digital pictures would help too.

David I assume your pics are taken in rainbow any particular reason for that. I have not played with the rainbow or the iron gray much guess I should start HUH

You stated summer and morning I would have to think attic still warmer at the top that red is about where the rafters would start, solid wood behind would be warmer than any sheathing behind the vinyl

Interior of house is cooler than exterior. Possibly insulated siding that had a peice replaced at some point with regular non-insulated siding

Difference appears to symetrical to be moisture alone, possibly insulation missing from wall cavity or siding as mentioned above.

I was thinking the same thing, Paul.

To my untrained eye:
Is the fireplace gas? Could it be the gas line?
What is the thing to the bottom left of it? Hose bib?

I don’t think there is enough information to make a definative answer.

Could be a manufacturer defect in that particular panel.
Could be a thicker material than the rest of the siding.
Might have been damaged and replaced with a different manufacturer material than the original siding.
Might be installed tight rather than loose like the rest of the siding.
Might have been replaced by home owner and glued in place rather than installed properly (sounds strange I know, but trust me I have seen home owners do this)

It’s too uniform (looks like an entire panel) to be a major concern. I would probably note it to myself, take photos, and move on.

Was there a layer of rigid insulation or foil-faced “level wall” installed under the siding. Looks like a piece missing. Easy for the siding guys to cover over a small void.

I would like to start by commending everyone for their input in this brainteaser. This is a perfect example of why we wanted to form this section in the NACHI bulletin board. I applaud all of you. There are going to be things that we just cannot explain because of the limitations that we are bound by. However, in future inspections one of you may encounter the solution to this question and will enlighten the majority with your wisdom.
A little bit of tension has erupted on this thread since its inception because of previous posts and I sincerely hope that we can work past this. Everyone has an opinion and a theory. Let’s be tolerant of one another. This is new to all of us and to the rest of the world. There is no expert in this field yet. Those that taught us what we know have admitted that they have achieved where they are by trial and error. We all have a perspective and an opinion. If you post it, be prepared to support your theory. Anyone questioning your theory is not attacking you, rather trying to broaden our perspective.

I did look behind the slip joint but did not see anything.

I’m quite certain that the dew point temperature was well below 85° which was the ambient outdoor temperature.

I tried to find them, but they are on another computer. Basically we’re just looking at one section of vinyl.

I changed it to rainbow to accentuate the scan.
By the way, I have found some better pallets in QuickView versus quick report for some applications. I will post this later in another thread.

As for other than black and white scans, we use what we have to, to depict the point were trying to make. It should be noted that any other setting degrades resolution. But the more you play with your scan, the better you may be able to relate the issue to your client.

The heat at the roofline is because there is a cathedral ceiling. Also there was some deficient insulation in the attic.
The sheathing behind the vinyl seemed rather consistent for normal construction. Good call!

It took thermal scans on the interior wall and did not discover any anomalies from the inside. I could only see the temperature difference on the exterior vinyl siding layer. Good point!

There is no gas line in the wall. The temperature difference appears to be isolated to one sheet of vinyl siding. Good point!

I agree. I gathered as much information as I could. There is no significant deficiency associated with this condition. There was no supportive testing of any kind to direct a further evaluation. We are just trying to see if anyone out there has come across this situation and has found an answer to this situation.

Nothing that I could determine through a noninvasive examination.
I also had these thoughts. Good consideration.

I have quick report where do I find quick view .
Thanks …Cookie

I really like the mid-gray and mid-green palettes to make the contrast easier for the client to see.


Do you own a borescope? A small hole can show alot. Also I learned to not use the rainbow color pallette on the camera during a ITC Building Science course. You will get the best resolution fron the Grey scale. Not as exciting as the rainbow but much better for figuring out anomalies. Try this yourself and you will see a difference. Also remember Emissivity and focus are essential to good thermograms. What time of day was the IR taken?

Yes, I do own a bore scope. I did look through the slip joint of the siding but did not find anything substantial. In this particular case, I do not feel there is a significant deficiency but I am very interested in what caused the thermal anomaly seen.

I used the grayscale during the inspection but changed it afterwards in my computer program to enhance temperature change and boundary. Most people have a hard time seeing things in black-and-white so enhancing the scan in color makes the temperature gradient more obvious to the untrained eye. You are correct, resolution is much higher in the grayscale. Rainbow (which is used extensively in advertising infrared equipment) has the least resolution but has a greater WOW factor.

I use color in the manual mode when I’m doing fast walk through inspections just to look for specific issues, such as overheated electrical circuits or to verify air flow from HVAC supply air registers. It shows up faster that way. Then I change back and adjust the camera if I find a problem.

Focus is, emissivity is not essential to good thermograms. Emissivity is only necessary to determine the actual versus apparent temperatures. The a bolometer (if focused) will record the same data in a camera regardless of your emissivity settings.

See the difference between this black-and-white and those I posted above?