How to Finish the Installation
It is important to seal the new window in the opening
to direct any water away from the interior and into
the drainage system of the wall. That is usually
behind the stucco, and down to the bottom weep
within the wall.
Two goals must be met. First, no water that enters
the installed window cavity should get behind the
window and into the interior. Second, no moisture
shall enter the cavity where it can condense and
become trapped.
All gaps over 1/8” that are sealed with caulk, must
use backer rod. All gaps over must be covered with
trim, or any means to block water penetration into
the opening.
The preferred method for trim/sealing the interior
and exterior is Snap Trim.  Pvc windows are fitted
with an accessory groove into which trim can snap
that will bridge any gap, and maintain drainage out 
of the cavity and away from the window as shown.
Aluminum windows can utilize two piece aluminum
snap trim, where one piece is screw anchored to the
frame, and the finish piece is snapped in place to
effect a complete trim cover of the perimeter joint.
All snap trim is cut to where the header portion 
passes over the top edge of side pieces, and where 
the bottom piece fits between the 2 side pieces. 
This effects the proper “shingle-style” overlap
drainage.
Exterior joints can be caulked, interior joints are best
left un-caulked to maintain vapor barrier continuity
in warm/humid coastal areas.
If the stucco is damaged, the new installation will require a lot
of repair as shown. Be careful, put in new bucks, and you can
minimize the problem, and comply with code.
Window Fitters Guide to Window Installation 
137              ©2022 AWDI, LLC Do not reproduce without permission
Alterative
Using 
snap-in 
trim
new 
windows 
can be 
mounted
easily - 
especially 
with 
pre-formed
cast sills.
SAMPLE MANUAL

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