spaced a minimum of 12 inches OC. A nominal 1- by
3-inch or 1- by 4-inch wood member can be used for
roof or ceiling members spaced not more than 24 inches
OC. A nominal 2- by 2-inch or 2- by 3-inch member
should be satisfactory for truss or ceiling joist spacing
of up to 48 inches.
In locating the strips, first measure the width of the
room (the distance parallel to the direction of the ceiling
joists). If, for example, this is 11 feet 6 inches, use ten
12-inch-square tiles and 9-inch-wide tile at each side
edge. The second wood strips from each side are located
so that they center the first row of tiles, that can now be
ripped to a width of 9 inches. The last row will also be
9 inches, but do not rip these tiles until the last row is
reached so that they fit tightly. The tile can be fitted and
arranged the same way for the ends of the room.
Ceiling tiles normally have a tongue on two adjacent
sides and a groove on the opposite adjacent sides. Start
with the leading edge ahead and to the open side so that
it can be stapled to the nailing strips. A small finish nail
or adhesive should be used at the edge of the tiles in the
first row against the wall. Stapling is done at the leading
edge and the side edge of each tile (fig. 5-26, view B).
Use one staple at each wood strip at the leading edge
and two at the open side edge. At the opposite wall, a
small finish nail or adhesive must again be used to hold
the tile in place.
Most ceiling tile of this type has a factory finish;
painting or finishing is not required after it is placed.
Take care not to mar or soil the surface.
INSULATION
LEARNING OBJECTIVE: Upon completing
this section, you should be able to identify the
types of insulation and describe the methods of
installation.
The inflow of heat through outside walls and roofs
in hot weather or its outflow during cold weather is a
major source of occupant discomfort. Providing heating
or cooling to maintain temperatures at acceptable limits
for occupancy is expensive. During hot or cold weather,
insulation with high resistance to heat flow helps save
energy. Also, you can use smaller capacity units to
achieve the same heating or cooling result, an additional
savings.
Most materials used in construction have some
insulating value. Even air spaces between studs resist
the passage of heat. However, when these stud spaces
are filled or partially filled with material having a high
insulating value, the stud space has many times the
insulating ability of the air alone.
TYPES
Commercial insulation is manufactured in a variety
of forms and types, each with advantages for specific
uses. Materials commonly used for insulation can be
grouped in the following general classes: (1) flexible
insulation (blanket and batt); (2) loose-fill insulation;
(3) reflective insulation; (4) rigid insulation (structural
and nonstructural); and (5) miscellaneous types.
The insulating value of a wall varies with different
types of construction, kinds of materials used in
construction, and types and thicknesses of insulation. As
we just mentioned, air spaces add to the total resistance
of a wall section to heat transmission, but an air space
is not as effective as the same space filled with an
insulating material.
Flexible
Flexible insulation is manufactured in two types:
blanket and batt. Blanket insulation (fig. 5-27, view A)
is furnished in rolls or packages in widths to fit between
studs and joists spaced 16 and 24 inches OC. It comes
in thicknesses of 3/4 inch to 12 inches. The body of the
blanket is made of felted mats of mineral or vegetable
fibers, such as rock or glass wool, wood fiber, and
cotton. Organic insulations are treated to make them
resistant to fire, decay, insects, and vermin. Most blanket
insulation is covered with paper or other sheet material
with tabs on the sides for fastening to studs or joists. One
covering sheet serves as a vapor barrier to resist
movement of water vapor and should always face the
warm side of the wall. Aluminum foil, asphalt, or plastic
laminated paper is commonly used as barrier materials.
Batt insulation (fig. 5-27, view B) is also made of
fibrous material preformed to thicknesses of 3 1/2 to
12 inches for 16-and 24-inch joist spacing. It is supplied
with or without a vapor barrier. One friction type of
fibrous glass batt is supplied without a covering and is
designed to remain in place without the normal fastening
methods.
Loose Fill
Loose-fill insulation (fig. 5-27, view C) is usually
composed of materials used in bulk form, supplied in
bags or bales, and placed by pouring, blowing, or
packing by hand. These materials include rock or glass
5-20
