Building Design and Construction Handbook - Merritt - Ventech!

1.14 SECTION ONE
1.4g). Figure 1.4h illustrates a variation of a monitored roof that is called a sawtooth
roof.
The basic element in a roof is a thin, waterproof covering, called roofing (Sec.
12). Because it is thin, it is usually supported on sheathing, a thin layer, or roof
deck, a thick layer, which in turn, is carried on structural members, such as beams
or trusses. The roof or space below should contain thermal insulation (Fig. 1.6c
and d).
Exterior walls enclose a building below the roof. The basis element in the walls
is a strong, durable, water-resistant facing. For added strength or lateral stability,
this facing may be supplemented on the inner side by a backing or sheathing (Fig.
1.5b). For esthetic purposes, an interior facing usually is placed on the inner side
of the backing. A layer of insulation should be incorporated in walls to resist
passage of heat.
Generally, walls may be built of unit masonry, panels, framing, or a combination
of these materials.
Unit masonry consists of small units, such as clay brick, concrete block, glass
block, or clay tile, held together by a cement such as mortar. Figure 1.5a shows a
wall built of concrete blocks.
Panel walls consist of units much larger than unit masonry. Made of metal,
concrete, glass, plastics, or preassembled bricks, a panel may extend from foun-
FIGURE 1.5 Types of exterior wall construction: (a) concrete-block wall; (b) wood-framed
wall; (c) precast-concrete curtain wall.