Is this reflection damage? Shall we call in the experts?

I had a 5.5 hr inspection one day in Potomac Maryland on a HUGE house. I spotted 2 areas like this with nothing around that could possibly have caused it. So I revisited the two areas and by early afternoon, both areas were lit up from windows! And the crazy thing is that the windows were on the house next door. I did lots of research and found out it is the specifically, Low E Windows. The only fix is to make changes to the window covering. There are several external applications such as Turf Shield that can fix the issue


Should make for a fun conversation with the neighbor: “Your windows are damaging my cheap vinyl siding. If I buy you some Turf Shield, would you mind if we install it on your windows?”

Anyway, thanks Brian for posting and everyone for the dialogue on this. I would have never thought of the reflection. I would still be chasing my arse trying to understand how the fireplace was causing that.


Most window manufacturer’s have a solution to “Thermal Distortion” in the form of capillary windows which will not reflect concentrated sunlight in the same way. Of course, if the home is newer (and the windows are newer) the parts (window glass) are often available free of charge from the window manufacturer. If it is older, it’s probably a billable item. When I was building homes, we almost never ran into this until we started installing energy efficient (Low-E) windows—then it happened all the time. Here in the People’s Republic of Ohio, it’s much more likely to happen in the winter when the sun is lower in the morning sky (giving a more direct reflection and lasting longer than the summer sky). Just my two cents! All the Best!


I did not know this was a thing. Thanks for the information. I included a link for others.


Reflected damage likely…it didn’t affect the corner board because it is white (which reflects more) and likely a different formulation (more heat resistant).


Right!!! When this type of damage is in an area where its possible other factors may be in place it is hard to determine an exact cause unless we start ripping those walls down.

My Narrative … “We observed damaged vinyl siding at the chimney chase area. This could be caused by window reflection, the interior fireplace, excess heat or other causes. Have a competent contractor evaluate and repair as needed.”

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@dbowers Excellent.

I’d be interested in knowing how hot that reflection is? I couldn’t find anything in my research, just wondering if anyone else saw anything where it stated at what temperature the vinyl or astroturf was reaching as it melted, and the basic physics of how it caused such a hot reflection. Just wondering…it has to be pretty hot. Would assume hot enough to start things on fire, rather than just melt plastic siding and grass.

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According to this article:
Concentrated light reflected by energy efficient windows can create patches of heat that measure well above 200 degrees Fahrenheit.

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Hey Brian - I’ve encountered the vinyl distortion quite a bit (here in Virginia), and I usually account it to solar reflection from windows (or the neighbor’s windows). With that said - I do not recall seeing it as extreme as in your photos. I’ve seen plenty of really bad ones caused by poorly placed BBQ grills, which would not be the case here.
And although I’m not there to see which way the building is facing, or how the Sun shines (direction/duration), I tend to think that THAT would be some puzzling geometry for Solar Reflex.
So I’m wondering…go with me here… could it be related to the fireplace? Such as improperly installed or improperly insulated flue/draft components. Cuz - look at that black area on the slab edge below. Is that charring or loose soot of some kind? I don’t see that condition anywhere else on the slab edges.
Anywho…I would describe it to client as “area of distorted vinyl siding present. Cause of this condition cannot be confirmed by this general inspection. Proper qualified repairs recommended. Qualified service should include evaluation of components behind/under this area (such as those components or equipment not accessible or visible during this general inspection)”.
Just an opinion. YMMV.

I went back and looked at a few photos in high resolution, the soot is a damp area with a little mildew.

I agree, we should be careful discounting a possible fireplace issue.

I’m curious though, has anyone seen a heat problem from one of these vents?

Never in 25+ years.


There is no doubt in my mind that this was caused by window reflection. You can see the reflection of that corner right in the window. So if the sun hits it at the same angle, voila.
Here is a good link on this topic. Vinyl Siding Solar Reflection - Prevent Exterior Dammange - VSI and from Cardinal Glass.


Hi Jeffrey! Sorry for the late response, somehow I missed this.
Yup, that’s real funny, almost an exact duplicate of that thread! And for sure it’s the reflection.
You posted a comment recently where double lugging was involved and you said that double lugging and double taps are not the same thing. I want to respond to that thread but I can’t find it. I looked high and low, I find it very hard to find past posts. Can you send me that thread so that I can respond to it? You always have lots of good information.
Thank you!

Eli Klugmann
Best Nest Inspections LLC


I’ll see if I can find it, but this Forum really suks when you can’t find a post from a few days ago!!

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Thanks Marcel. That isn’t the one from a few days ago that Eli is referencing, but still good stuff.


I think this is it… Cloth wire or cloth sheathed non metalic cable? - #15 by jjonas

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Am curious to know what the sunlight angle is in relation to the window and its warping. Is this damage west-facing?