Instructions / Assembly

INSPECT ROUGH OPENING (R.O.)
2
A
D
C
E
B
Trimmer
studs
Sheathing
Header
King
stud
Trimmer
studs
Installation Instructions
for Vinyl Bay/Bow Windows with Integral Nailing Fin (JII-90025)
4
The use of a sill pan and other barriers will decrease
the rough opening height clearance. Adjust the
opening dimensions accordingly.
• Verify the width and height of the rough opening is 1/2"-5/8" larger
than the window width and height.
• Verify the rough opening
is square. The (A) and (B)
measurements should be the
same. Suggested deviation
from square is no more
than1/4".
• Verify the rough opening is
level and plumb (C, D and
E). Suggested deviation from
square is no more than 1/8".
• The rough opening sill should
not be crowned or sagged
(D), but rather level or sloped
(positive slope) to the exterior.
• The exterior face of the rough opening should be in a single plane (E)
with less than 1/8" twist from corner to corner.
• Minimum double studs (king and jack/trimmer) should be used to
support the header at all rough openings.
For Retrot Installations
Verify the rough opening framing is structurally sound. Contact your local
waste management entities for proper disposal or recycling of products
being removed.
This installation guide only addresses sheathed wall, open-stud
construction and exterior foam insulation. For exterior foam
insulation construction, please reference FMA/AAMA/WDMA 500 for
additional install and framing details. If installing into an opening
other than what is identied, consult a building professional.
Fully Sheathed Wall Construction
Sheathing is applied to the
exterior of the wall framing.
The window will be
mounted ush against the
sheathing or building wrap
in a weatherproof manner.
Verify Square, Level and Plumb
Exterior Foam Insulation Construction
Exterior Foam insulation
is applied to the exterior
of the wall framing. The
window will be mounted
to a structural support
member on the same
plane as the exterior
foam insulation in a
weatherproof manner
(refer to FMA/AAMA/
WDMA 500 for additional
install and framing details).
Open-Stud Construction
Sheathing is absent and
building wrap is applied
atop of the wall framing.
The window will be
mounted ush against
building wrap and/or
framing members (studs).
Exterior foam
insulation
Structural
support
member