Window Fitters Guide to Window Installation 
50                ©2022 AWDI, LLC Do not reproduce without permission
Replacing Old PVC
Pocket Window
Pocket Replacement Windows have been popular for
more than 50 years and as good as many of today’s
popular brands are, there are also many that have
not weathered very well - especially earlier ones made
with inferior uPVC and thin wall extrusions.
Early Vinyl Replacement Windows were mechanically
fastened which warped and leaked air, These early
vinyl windows followed the design and fabrication
methods of the aluminum replacement windows that
preceeded the rise of PVC frames. Some were 
side-load with even less weatherstripping
Early glazing systems did not stand the test of time
with an average life before seal failures fogged the
glass. Finally, early window systems have been 
abandoned in favor of more robust and energy 
efficient designs making spare parts hard if not
impossible to find.
Today there is a growing need to replace the old
replacement windows. The good news is that it is
possible to remove windows installed in the left-in-
place sash pockets of the old wood double hung 
windows that were replaced.
Replacing old Pocket Vinyl Windows is an excellent
opportunity to upgrade the install by redoing old
inside-out installs with better outside-in installs
eliminating the need for a head expander and 
applying new and more weather-tight exterior trim.
Detailed in this section is a simple methods to
remove the old pocket windows and place a modern
energy efficient model in its place with minimum dis-
turbance damage to the old wood frame.
Caution: It is very important after removing the old
pocket window to check the old window frame where
the new window will go. Probably only the old
replacement window failed, but if water penetrated
around the old replacement window it might have
started rot, mildew or other damage that should be
carefully assessed to mitigate the problem and treat
the receiving wood frame to avoid further damage. In
extreme cases, the old wood window may need to be
completely removed down to the rough framing
(Frame-Out Replacement) as detailed elsewhere in
this book. 
Bottom Line: Care is necessary to make sure the
complete weather barrier of the window/opening
joint is complete.
Glass Failure
Condensation
Warped Frame
Old Mechanically Fastened Frames
SAMPLE MANUAL

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