Figure 4-25.-Out-swinging casement sash.
Sash may be divided into a number of lights (glass
panes or panels) by small wood members called
muntins. Some manufacturers provide preassembled
dividers, which snap in place over a single light,
dividing it into six or eight lights. This simplifies
painting and other maintenance.
Assembled frames are placed in the rough opening
over strips of building paper put around the perimeter to
minimize air infiltration. The frame is plumbed and
nailed to side studs and header through the casings or
the blind stops at the sides. Where nails are exposed,
such as on the casing, use the corrosion-resistant type.
Hardware for double-hung windows includes the
sash lifts that are fastened to the bottom rail. These are
sometimes eliminated by providing a finger groove in
the rail. Other hardware consists of sash lockss or
fasteners located at the meeting rail. They lock the
window and draw the sash together to provide a
Double-hung windows can be arranged in a number
of waysas a single unit, doubled (or mullion), or in
groups or three or more. One or two double-hung
windows on each side of a large stationary insulated
window are often used to create a window wall. Such
large openings must be framed with headers large
enough to carry roof loads.
Casement windows consist of side-hinged sash,
usually designed to swing outward (fig. 4-25). This type
can be made more weathertight than the in-swinging
style. Screens are located inside these out-swinging
windows, and winter protection is obtained with a storm
sash or by using insulated glass in the sash. One advan-
tage of the casement window over the double-hung type
is that the entire window area can be opened for
Weather stripping is also provided for this type of
window, and units are usually received from the factory
entirely assembled with hardware in place. Closing
hardware consists of a rotary operator and sash lock. As
in the double-hung units, casement sash can be used in
a number of waysas a pair or in combinations of two
or more pairs. Style variations are achieved by divided
lights. Snap-in muntins provide a small, multiple-pane
appearance for traditional styling.
Metal sash is sometimes used but, because of low-
insulating value, should be installed carefully to prevent
condensation and frosting on the interior surfaces during
cold weather. A full storm-window unit is sometimes
necessary to eliminate this problem in cold climates.