What Melted this Vinyl Siding?

Hello y’all.
I am reaching out for some of that experienced NACHI assistance on a situation I encountered and have never heard of nor seen anything like it. I inspected this home and the vinyl siding appears to have melted in several locations - by the A/C auto shut-offs, on the chimney, adjacent to the A/C compressor. None of those should have caused this…or could it?
I am including several pictures which should be legible. If not please let me know so I can figure out what went wrong.

Thanks in advance for any and all input.
Have a Groovy Day.

randy c

If this is near the chimney or fireplace, I would take a real good look at the flue and the firebox.

Where in relation to the electrical panel is the fireplace??

It’s more likely from the sunlight being reflected off those window behind the AC unit. Notice how there is a small area under the electrical box that is not blistered? That’s a shadow area created by the box. The upper level part is probably from the upper windows reflection. I’ve seen this a couple of times, the strangest was from a neighbors house. But like Shawn said, since this is on the fireplace, you should definately recommend a Level II inspection to be sure that isn’t the source. (My answer isn’t that big a deal, a leaky fireplace will kill.)

I was thinking the same thing as Mark. Reflection. But Shawns’ answer does possibly make sense.

Relections off the windows and exterior walls.

I also wonder about those vents in picture two.
one appears to be a dryer vent but is right next to the compressor .
Also laying on the ground is PVC piping that appears dismantled.

In the background I also see what looks like schedule 40 .
Both of the above seem to be in the wrinkled area and the liquid tight looks as if it is rusting prematurly.

Tough call on that one Bob, but did find this that looks like the pictures above and caused by the dryer vent.



Wow it looks like the same place.

Now I really wonder what the other vent is for?

Without being there we can only guess.

I’ve seen that 3 times in 4 years. Thermal damage caused by the sun’s reflection is what I always assume. Recommend an evaluation by a siding specialist.

What’s puzzeling, is that I have the same siding on my house with the vinyl dryervent adaptor that comes as an accessory and no way did it damage my siding from using the dryer.

I’ve seen similar damage from barbeque grills, but this photo is not from that either.
That is a good one for sure to figure out. :slight_smile:

Here you go everyone.

That’s not a dryer vent. Just a hood to cover the entrance of all the piping into the wall cavity. Very common around here.

Thanks Joe;
That was very interesting Joe, never seen or heard of this before, but did see a few comments below that were from Maine.
Got to be a defective product to distort like that from mere reflections.
The back side of my house is directly in the sun all afternoon in the summer and shows no sign of distortion.

This could be an issue of cheap vinyl siding also. I bet it was nowhere close to a 55 mil product. :slight_smile:

More discussion on this phenonmena on Active Rain.

Interesting Article here from VSI on the subject.
Worth a read.


Not really a dryer vent. Very common here to use this type of vent cover to protect freon lines, condensate lines, etc. entering home.

(Good one Joe)

The PICs all appear to show that the melting is occurring on the same side of the house. I’d guess the sun reflecting off the neighbor’s high-efficiency, mirrored windows.

Not all vinyl siding is created equal. I started getting a trade magazine a few years called Coastal Contractor and found out there are thicker, higher grade vinyl sidings used specfically for coastal and high wind areas as well as the high UV damage areas (all of which is FL). This stuff stands up the the heat, sun, wind, cold, sand abrasions, etc. (btw, this is not the stuff off the shelf at HD and lowes).

One site is:


Exactly Doug, and when I did mine, I bought the thickess available and don’t regret it at all. :):smiley:

Didn’t y’all ever fry a bug with a magnifying glass, or at least start paper on fire.

In pic 1 (establishing shot is always helpful, the sun is from the left at about 3:30 PM.

In pic2, you could fry an egg in that bright spot, vinyl siding doesn’t stand a chance. I’d bet even the thick stuff won’t hold up to this for long. It’s just ending it’s run across the melted spot. And it does this day after day during the right time of year. The melted spot is just to the right of the sliding doors in picture one. You can see a bit of the doors in pic 2 at the left side.

Here’s an even better picture from Joe Perry, down in Charleston, SC. Ya just gotta be there at the right time of day and year.

Fried bugs, anyone??