Window Fitters Guide to Window Installation 
16                ©2022 AWDI, LLC Do not reproduce without permission
Using Spray Foam
For the best installation, it is necessary for the gap
around the window or door to be sealed to block out
air, water and vapor penetration. ccSPF can do that
well if selected and used properly. Improper use can
create water traps, impede drainage and exert exces-
sive pressure to the window frame during expansion. 
Remember: Vapor barriers need to applied on the
warm side of the opening. Double vapor barriers 
(one on the warm side and another on the cool side)
encourage condensation between and will trap the
resulting condensation. Also, window installation
cavities (the space between the window frame and 
the rough opening, or left-in-place old window frame)
need to “breathe” to the outside, and allow drainage
of collected water to the outside.
AWDI recommends ccSPF’Foam which is a
polyurethane closed cell, low pressure/low expansion
sealant to fill the gaps as protection against moisture
and air. OSI's closed cell foam also achieves a 
thermal performance of R5 per inch.
Application
Foam can be applied using a Foam Applicator Gun,
or a small can with “straw type” nozzle tip.. The flexi-
ble tip from gun or can equally allows for more pre-
cise application. This gun offers a rear valve used to
control the size of bead applied into the openings.
The valve also allows the life of the foam to
be extended by closing the opening of the
barrel for future use.  
For even smaller openings, a detachable
screw on top is included with the gun to
be able to fill gaps as small as ¼1/8”
wide.
Important tips:
• Similar to the sealant gun, it is critical that you 
balance the movement of the foam gun or straw 
barrel and how you dispense the foam so that the
foam makes contact with both the rough or existing
window frame and replacement window frame.
• If the dispensed foam does not make contact with
both the rough frame and the window frame, there
won’t be an adequate bond to seal out water and air.
• Industry Standards suggest application of 1 inch
beads, separated by an equal space. Be careful not 
to create two vapor barriers - one at the exterior and
one at the interior. Make sure there is the ability for
the opening to breathe to the cold side for drying and
drainage. Use backer rod about one inch in the sill as
a stop to make a workable back dam
• When applying foam around the perimeter of the 
window or door, you must maintain a minimum
depth of 1 inch. This depth is required to provide 
the correct thermal performance, to help improve
energy savings, and to protect against condensation
problems.
• When applying foam as a back dam to the gap
between the window frame and the rough sill, do 
not allow the foam to extend to the exterior edge of
the opening. Maintain a minimum of a 1 inch gap
between the foam and the exterior edge of the rough
sill. If foam fills this gap at the sill, any water from
leakage will not be able to drain to the drainage plane
or exterior cladding surface. Place backer rod the
length of the sill, 1” from edge and use it as a back
dam guide.
Backer Rod
1”Set Back
Foam
Bead
Foam
Bead
SAMPLE MANUAL

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