What’s Warping That Siding?

As a home inspector in New Jersey you will see a great number of homes cladded with vinyl siding. Sometimes you will see a square of patch of cladding that looks like partially melted siding on the side of a house. It is easy to figure out the cause if the patch of siding is over a gas barbecue, near a direct vent for a fireplace, or other fixed heat source. It is a problem when there is with no apparent reason causing the distortion.

To get to the bottom of it you will need to visit that house at the perfect time. That time would be when the sun is out and reflecting off the high tech, low emissivity glass that is installed in the windows of the home at a perfect angle to hit that siding. That glass is low emissivity because it reflects about a third of the solar energy striking  the window, reducing solar energy entering the home. The widow is reflecting quite a bit of energy. It not only reflects the solar energy but focuses it much the same way a lens focuses light energy, the window also being a lens. This reflected, focused energy projects onto the siding nearby, and as a result, the vinyl cladding starts to absorb the energy and heats up, approaching its melting point and changing its shape. Sometimes the reflected energy can even come from a neighbor’s window to cause this melting, if close enough.

There is no easy fix for this either, unless you are willing to take the expense of siding the house with a more heat resistant material, or get rid of your nice, energy efficient windows. Both poor and expensive options. And there is no vinyl siding available right now that is resistant to the level of heat that can be generated. The most common way to deal with the situation is to block the radiation in some way. You can do this with a decorative screen or the use most common method; plant a tree (an evergreen) in the path of the radiated heat.  The designer of the home, or architect, should take this phenomena into consideration when planning the position and orientation of the windows and walls of the home to avoid the issue. -Submitted by John Bittner 3/19/19.