Roof, gutters & exterior

Vinyl siding warped or melted

Wavy or melted-looking vinyl siding is most often caused by reflected sunlight off a nearby energy-efficient window, not a defect in the siding itself.

Difficulty
Moderate
Time
1–2 hours to diagnose
DIY cost
$20–$60
Pro cost
$200–$800

Symptoms

  • Siding appears wavy, rippled, or shrunken in a localized area
  • Melted or bubbled look to the surface
  • Damage pattern lines up with a nearby window's reflection angle

Likely causes

  • CommonReflected sunlight from a low-E energy-efficient windowCertain window coatings can concentrate reflected heat enough to distort vinyl siding at specific times of day and year.
  • CommonGrill, fire pit, or other heat source placed too closeDirect radiant heat from grills or fire features can warp siding nearby.
  • PossibleDirect flame or extreme heat exposureA close fire source can cause more severe melting than reflected sun.

What to do

  1. Note the time of day and season the distortion seems to worsen, and check for a nearby window at a matching angle.
  2. If a window reflection is the cause, consider window film, an awning, or landscaping to diffuse the reflection.
  3. Move grills, fire pits, or other heat sources several feet further from the siding.
  4. Replace already-damaged panels, since warped vinyl won't reshape itself back to normal.
  5. Check with the window manufacturer or installer, since reflective melting from windows is a known issue some warranties address.
  6. Consider a heat-resistant or fiber-cement siding option for the affected area if the reflection issue can't be eliminated.
  7. Monitor the repaired area through a full sun cycle to confirm the fix worked.

Tools and parts

  • Vinyl siding zip tool
Replacement vinyl siding panelSearch: “vinyl siding panel replacement”

When to call a pro

Call a siding contractor or the window manufacturer to address a reflective melting issue causing repeat damage.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.