ALCOA vinyl siding one side warping, why?

Background: House located in Connecticut, Vinyl siding, 9 yrs old, 2 famiily house, warp one side only-north side, faces neighbors house which receives south sun, warping affects 2/3 side starting from roof line down to 1st floor windows, warping first noticed in Feb 07- 3 mos ago. Neighors house approx 25 ft distance. Manufacturer analysis of sample piece showed damage appears to be heat related. Claims vinyl heated in access of 160 degrees. Hose has been inspected for heating & cooling system issues-none found. Manufacturer states neighbors windows reflect sunlight onto my home which caused my vinyl to melt & warp. Hard to understand as this happened in the winter months and neighbors windows are 25 ft away.

Question: Is this possible? and could there be another cause? If I repair this, won’t it happen again? Why would a maufacturer make and sell a product that would be prone to warping if placed on a house with neighbors nearby? shouldn’t there be a warning or shouldn’t the contracter have informed me that this could happen? Most of the 2 & 3 family homes in this city are vinyl sided, therefore if this is a common problem, wouldn’t there be many many homes with melted / warped siding?

Please email me with all thoughts / advice…etc. MUCH appreciated!

It’s possible.

The few times I’ve seen it, the reflective surface has been within a few feet of damaged siding (usually at a corner, or beside a casement window) and the area of damage has been a few feet square or smaller. BTW, pavement reflections are supposed to be a possible cause as well, though I have never seen this.

Vinyl siding expands and contracts on a regular basis. If it is nailed too tight to the sheathing it doesn’t allow the siding to contract back to its regular size and it will look warped. It’s possible that this is the issue and it’s just gotten worse over time and are only know starting to notice it. If you pull up a couple of pieces the nails should not be tight to the sheathing.


Exactly, could have been a new installer doing that side .

I have seen this several times. Typically, the neighbors have low-E windows and do reflect the sun. The last occurrence we inspected was in Feb. Outside temp was in the 30’s but the siding and refection was so hot you could not hold your hand in place. The windows were ~ 35 feet away from the siding and actually left marks you could set a clock or calender by. The fix was either block the reflection with blinds, fence, or trees or replace the siding with a less sensitive siding.