Standard Practice For Installation of Windows With
Integral Mounting Flange in Wood Frame Construction
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This practice has been approved as an industry standard by the
California Association of Window Manufacturers (CAWM) Technical Committee and
by general membership ballot as of June 26, 1995.
1. Scope
1.1
This practice covers the installation of windows in residential
buildings of no more than four (4) stories in height.
1.2
This practice applies to metal and non-metal framed windows when
an integral mounting flange is employed for installation.
1.3
This practice covers the installation process from
pre-installation procedures through post-installation procedures. It does not
cover the fabrication or assembly of units whether such fabrication takes place
in a factory or at the intended installation site.
1.4
This practice covers aspects of installation relating to the
effectiveness and durability in service. It does not cover aspects relating to
the safety of the person installing the units.
1.5
This practice provides minimum requirements that will help to
ensure the installation of windows in an effective manner. Actual conditions in
buildings vary greatly, and in some cases substantial additional care and
precaution will have to be taken.
1.6
This practice does not purport to address all of the safety
problems associated with its use. It is the responsibility of whomever uses
this standard to consult and establish appropriate safety and health practices
and determine the applicability of regulatory limitations prior to use.
2. Referenced
Documents
2.1 ASTM:
B 633 “Standard Specification for Electrodeposited
Coatings of Zinc on Iron and
Steel”
B 766 “Standard Specification for Electrodeposited
Coatings of Cadmium on Steel”
B 456 “Standard
Specification for Electrodeposited Coatings of Copper plus Nickel
plus Chromium and Nickel plus
Chromium”
C 755 “Practice for
Selection of Vapor Retarder for Thermal Insulation”
D 779 “Standard Test
Method of Water Resistance of Paper, Paperboard, and Other
Sheet Materials by the Dry Indicator Method”
2.2 AAMA 800
“Voluntary Specifications and Test Methods for Sealants”
3. Definitions
3.1 Galvanic
Corrosion - A form of deterioration of metal resulting from the
electrochemical reaction that occurs when certain dissimilar metals are in
contact in the presence of moisture.
3.2 Residential
Building - Any building used or intended primarily for a single or
multiple family dwelling.
3.3 Mounting
Flange - A fin projecting from the window frame parallel to the plane
of the wall for the purpose of securing the frame to the structure.
4. Significance and
Use
4.1 This practice
recognizes that effectiveness and durability of installed units depend not only
on the choice and quality of materials, design, adequacy of assembly, and
support system, but also on their proper and workmanlike installation.
4.2 Improper
installation of units may reduce their effectiveness, lead to excessive air,
water and sound leakage, condensation, and may promote the deterioration of
wall constructions, windows, doors, and their respective finishes.
Additionally, improper installation of metal units may result in accelerated
corrosion of metal frames, trim, anchors, fasteners, and finishes.
4.3 The application of
this practice also requires a working knowledge of applicable Federal, State,
and local codes and regulations, specifically, but not limited to required
means of egress and requirements for safety glazing. Consult with local
building codes prior to installation.
4.4 The application of
this practice also requires a working knowledge of the tools, equipment, and
methods necessary for the installation of windows. It further assumes
familiarity with caulking and sealing and with glass handling procedures,
painting where applicable, and an understanding of the fundamentals of
residential construction that affect the installation of these units.
5. Procedure
5.1 Framing
Requirements - The rough framed opening to receive the window shall be
sufficiently larger in width and height than the actual frame dimensions of the
window. To assure adequate clearance, the framer shall consult the
manufacturer’s literature for the recommended rough opening dimensions. The
framing shall be plumb, square and level. (See Figure 1)
5.2 Protection
from Dissimilar Materials
5.2.1 Aluminum
products shall be isolated from dissimilar or corrosive materials with a
nonconductive coating or sealant material.
5.2.2 All fasteners
shall be corrosive resistant, in accordance with ASTM B 633, B 766, or B 456.
5.3 Flashing
Requirements - Proper flashing and/or sealing is necessary as a
secondary barrier to prevent water from entering the wall between the window
frame and the adjacent wall materials. Flashing and/or an appropriate method of
sealing shall be designed as a part of an overall weather-resistive barrier
system. It is not the responsibility of the window manufacturer to
design or recommend a flashing system
appropriate to each
job condition.
Note 1 - The responsibility
for protecting any flashing material from damage caused by weather, other
trades, or vandalism, and properly integrating the flashing system into the
weather resistive barrier for the entire building, will be the responsibility
of the general contractor or his designated agent.
5.3.1 Penetration
Flashing Material - Flashing material shall be barrier coated
reinforced and shall provide four (4) hour minimum protection from water
penetration when tested in accordance with ASTM D79. Flashing material shall
carry continuous identification.
5.4 Application
5.4.1 One of the two
following methods shall be selected as the application to be followed. Once a
method is selected, all procedures of that method must be performed in the
described sequence. Substitution of a procedure from one method to the other is
not permitted.
5.4.1.1 Method A
5.4.1.1.1 A strip of
approved flashing material should be at least nine inches wide. Flashing shall
be applied in a weatherboard fashion around the full perimeter of the opening.
5.4.1.1.2 Apply the
first strip horizontally immediately below the sill, cut it sufficiently long
to extend past each side of the window, so that it projects beyond the vertical
flashing to be applied later. (See Figure 2)
5.4.1.1.3 Fasten the
top edge of the sill flashing to the framing, but do not fasten the lower edge,
so the weather resistant building paper applied later may be slipped up and
underneath the flashing in weatherboard fashion. (See Figure 2)
5.4.1.1.4 Apply a
continuous seal to the backside (interior) of the sill mounting flange, (see
Figure 3a). The window shall then be
installed in accordance with Section 5.5 installation procedures.
5.4.1.1.5 Next, apply
a continuous seal to the exposed mounting flange at the top (head) and sides
(jambs) of the installed window. For mechanically joined frames, apply seal at
corners the full length of the seam where mounting flanges meet. (See Figure
4a)
5.4.1.1.6 Starting at
each jamb, embed the jamb flashing into the seal and fasten in place. Run this
flashing beyond the sill flashing and above where the head flashing will
intersect. (See Figure 4a)
5.4.1.1.7 Finally,
embed the flashing into the sealant on the mounting flange at the window
head. Cut this flashing sufficiently
long so that it will extend beyond each jamb flashing. Fasten in place. (See
Figure 5)
5.4.1.2 Method B
5.4.1.2.1 A strip of
approved flashing material should be at least nine inches wide. Flashing shall
be applied in a weatherboard fashion around the full perimeter of the opening.
5.4.1.2.2 Apply the
first strip horizontally immediately below the sill, cut it sufficiently long
to extend past each side of the window, so that it projects beyond the vertical
flashing to be applied later. (See Figure 2)
5.4.1.2.3 Fasten the
top edge of the sill flashing to the framing, but do not fasten the lower edge,
so the weather resistant building paper applied later may be slipped up and
underneath the flashing in weatherboard fashion. (See Figure 2)
5.4.1.2.4 Next, fasten
strips of flashing at each vertical edge (jamb) of the opening. Run this
flashing beyond the sill flashing and above where the head flashing will
intersect. (See Figure 3b)
5.4.1.2.5 Apply a
continuous seal to the backside (interior) of the mounting flange near the
outer edge or a continuous seal to the perimeter of the opening at a point to
assure contact with the backside (interior) of the mounting flange. (See Figure
4b)
NOTE 2 - Caution must
be taken to avoid disrupting the continuous seal.
5.4.1.2.6 The window
shall then be installed in accordance with Section 5.5 installation procedures.
5.4.1.2.7 For
mechanically joined frames, apply seal at corners the full length of the seam
where mounting flanges meet.
5.4.1.2.8 Next, apply
a continuous seal at the top (head) mounting flange and embed the bottom of the
head flashing over the sealant and the mounting flange. Cut this flashing
sufficiently long so that it will extend beyond each jamb flashing. Fasten in
place. (See Figure 5)
5.5 Installation
5.5.1 Depending on the
size and weight of the window, shim blocks may be required under the sill to
maintain straight and level condition and to prevent rotation. Consult
manufacturer’s recommendations.
5.5.2 Shim and adjust
the window as necessary to achieve a plumb, square and level condition, as well
as an even reveal around the frame opening, securing it the full perimeter with
the equivalent of 6d fasteners on a maximum 16-inch centers. Hinged and pivoted
windows may require additional fasteners located near the hinge or pivot
points. For certain windows it may be appropriate to fasten the head in a
manner to allow for possible deflection.
5.5.3 In each
direction from all corners there must be a fastener within 10 inches, but no
closer than 3 inches, to prevent frame distortion or fracture of joint seals.
5.5.4 In all cases
consult manufacturer’s instructions for any special procedures or applications.
NOTE 3 - If any damage
to window frame joint seals is observed during installation, it must be
repaired by the installer.
5.5.5 Where
weather-resistant building paper, insulating board, or other materials by
other trades may constitute the primary weather barrier behind the exterior
wall finish (i.e. stucco, masonry, siding, etc.), Owner/General Contractor is
responsible to ensure that the weather barrier is continuous by effectively
sealing the material to the window frame. (See Figure 6)
5.6 Sealant
Requirements
5.6.1 Sealing/caulking
required between the window and the flashing can be accomplished with caulking
conforming to AAMA 800, or use sealant recommended and approved by the sealant
manufacturer.
5.6.2 Some exterior
wall finishes require additional sealing between the perimeter of the window
frame and adjacent finish wall material. Owner/General Contractor is
responsible for identifying the need for any additional sealant, which will be
applied by others. Such sealant shall be elastomeric material,
compatible with window framing and adjacent wall materials. (See Figure 6)
5.7 Finish And
Sealant Protection
5.7.1 Caution shall be
used to avoid damage to windows during and after installation. Prior to
installation, store windows in a near vertical position in a clean area, free
of circulating dirt or debris and protected from exposure to weather elements.
5.7.2 Field-applied
protective coatings can damage window sealants and gaskets and are not
recommended. Contact the window manufacturer before applying any such coatings.
5.7.3 Masking tapes
shall not be used on window surfaces as they may cause damage when they are
removed.
5.7.4 Stucco or
concrete left to cure on frames and glass will damage these surfaces. Remove
and clean all such materials from surfaces before any curing action takes
place.
5.7.5 Glass and frame
surfaces exposed to leaching water from new concrete or stucco must be rinsed
immediately with clear water to prevent permanent damage.
Fact Sheet Source
The material in this
fact sheet comes from the California Association of Window Manufacturers (CAWM)
“Standard Practice for Installation of Windows with Integral Mounting Flange in
Wood Frame Construction” and is being used with their permission.