Siding Distorted by Heat
On occasion we are called to look at siding that has been severely distorted over a small area (Figures 1 and 2).
What causes this? Sometimes we have seen the distortion due to heat from a barbeque grill being operated too close to the wall. But, when it is up on a second floor wall (Figure 1) we are usually able to rule out heat from a grill and we start looking around.
Ah, Ha! We see a nearby window pane with a curved surface (Figure 3).
In the subject case, the distortion in the siding is caused by solar reflection. Specifically, the sun shining on the nearby window is reflected onto the siding. Due to the curvature of the glass the light and heat are focused causing a severe heating. This is similar to igniting a piece of wood or paper by focusing the sunlight through a magnifying glass.
There is a helpful article on this topic at the Vinyl Siding Institute, Solar Reflection and Heat Distortion. Enjoy!