(C) J Wiley, S Bliss

PVC Solid Vinyl Windows - Warping Complaints & Solutions

  • Warping or shrinkage problems in vinyl or PVC windows: causes
    • Role of installation, weather, color, climate in vinyl or PVC window warping
    • How to control warping in vinyl windows
    • Expansion and contraction problems with vinyl PVC windows
    • Proper location of shims and screws to avoid warped vinyl or PVC windows
  • Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices
  • POST a QUESTION or READ FAQs about PVC windows

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Solid PVC or Vinyl Windows: this article discusses the cause and cure of warping in vinyl or PVC (polyvinyl chloride) windows.

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Warping PVC Vinyl Windows, Cause & Prevention

Readers should also see VINYL WINDOWS for details about PVC windows and their proper selection and installation , and see WINDOWS & DOORS our home page for window and door information, and also see WINDOW TYPES - Photo Guide for a photographic guide to window and door types and architectural styles.

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article, (see links at the end of this article) from Solar Age Magazine and written by Steven Bliss.

PVC Vinyl Window Warping Q&A

Question: What are the facts about the occurrence of shrinkage and warping in PVC or Solid Vinyl Windows?

I have heard some horror stories about shrinkage and warpage in extruded PVC (polyvinyl chloride) windows.

Can you get some factual information on solid vinyl window shrinking or warping problems? - Roy Berger, Architect Roy Berger and Sun, Des Moines IA


Problems in PVC or vinyl windows can be due to manufacturing or installation procedures, window color, or climate.

According to veteran plastic window maker Dan McCleary (Rehau Plastics, Leesburg VA in 1985), problems in solid vinyl or extruded PVC vinyl windows in the mid 1980's and how vinyl window shrinkage or warping problems were avoided were described:

PVC window units with welded corners can resist the stresses of thermal expansion better than vinyl windows whose components are screwed together with a metal bracket.

Holes punched out of the vinyl window frame for hardware or mounting screws were also a weak point - if the holes were badly punched or were too small, cracks could occur.

PVC (Vinyl) window warpage can be controlled by embedding a steel or aluminum bar inside the window frame, but this approach was considered limited by the size of the window frame. Many of the modern windows in the 1980's had a very narrow sight line - the amount of window frame that extends into the rough opening - which limits the size of metal bar that could be installed.

Window sash and frame color are another factor in PVC Window expansion problems. White or beige vinyl expands less than dark colored PVC because it absorbs less solar radiation.

According to McCleary, vinyl window color is not a problem north of the 50th Parallel in Canada and through most of Europe.

Some solid vinyl window manufacturers use white vinyl for the window core and add a thin overlay of pigmented vinyl that can move around (in response to thermal changes) without damaging the window.

Expansion and contraction problems in windows will be worse if the windows do not have room in their rough opening to expand or contract. Shims and setting screws used to install windows should be placed at least 8 inches back from the window corners to avoid these problems.

This article is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

Original aritcle

  • Q&A: Warped PVC Windows? - PDF version; use your browser's back button to return to this page. Original article, Solar Age Magazine, October 1985, adapted and updated for InspectAPedia.com December 2010.
  • FAQs below discusses field reports of problems & solutions for this topic


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