Window Fitters Guide to Window Installation 
56               ©2022 AWDI, LLC Do not reproduce without permission
NOTE: Projections over 8” require
Bracing, and a roof where soffits
do not sufficiently cover the win-
dow. Seat Depth roughly equals
Projection since the thickness of
the window & frame is approxi-
mately the same as the standard
wall depth of 4 1/2”.
Projection & Seat Depth
It is helpful to recognize the distance a Bay or Bow
Window will extend from the house and how deep the
seat board will be. Depending on the seat projection
and the thickness of the wall, installation will require
support — either corbel support, or cable support
illustrated elsewhere in this book. 
The installation procedure and support, as well as the
“roof” construction as needed, will be designed prior to
jobsite delivery. 
These illustration approximate the distances of projec-
tion and seat board depth. They may vary by a small
amount and are meant as an estimate only.
Bay Window Projections
Bay Windows usually are three windows only. The con-
figuration can consist of a picture window flanked by
two operable double-hungs or casements, or the center
unit can also be operable. Bay Windows come in two
standard angles of 30 degrees° and 
45 degrees.
The diagrams and chart 
show relative values of 
the dimensions for the 
assembled Bay Window 
assuming a standard 
Side Board Depth of 6"  
NOTE: Center Window Factor: 
Deduct Factor from total Bay 
Width to determine Center Window Size.
Garden Window 
Projections
Garden Windows are 
ordered from the 
factory to standards 
determined by the 
manufacturer. 
Check with the dealer for the projection and side
dimensions for a given height and width.
Bow Window Projections
A Standard Bow consists of 3, 4 or 5 lites, connected
by 10 degree angle mullions. The opening widths are
shown with approximate projections.
SIDE BOARD
SEAT BOARD
SAMPLE MANUAL

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