Braces are used to stiffen framed construction and help buildings resist the twisting or straining effects of wind or storm. Good bracing keeps corners square and plumb and prevents warping, sagging, and shifts resulting from lateral and external forces that would otherwise tend to distort the frame. Figure 6-22 shows three common methods of bracing frame structures: (A) let-in bracing, (B) cut-in bracing, and (C) diagonal bracing.

Roofs must be sloped so that they will shed water. The most common types of roof construction include the intersecting, the shed, the gable, and the hip (fig. 6-23). An INTERSECTING ROOF consists of a gable and valley or hip and valley intersecting each other at right angles. A SHED ROOF has a single surface that slopes downward from a ridge on one side of the structure. A GABLE ROOF has two surfaces sloping downward from a ridge located between the sides of the structureusually midway between them. A HIP ROOF is pitched on the sides like a gable roof and also is pitched on one or both ends.

The PITCH (amount of slope) of a roof is expressed as a FRACTION in which the

numerator is the UNIT RISE and the denominator is the UNIT SPAN. By common practice, unit run is always given as 12. See the roof pitch diagram in figure 6-24. Expressed in equation form,

Suppose that a roof rises 8 units for every 12 units of runmeaning that unit rise is 8 and unit run is 12. Since the unit span is 24, the pitch of the roof is 8/24, or 1/3. This value is also indicated in the center view of the roof pitch diagram in figure 6-24.

On construction drawings, the pitch of a roof is indicated by a small ROOF TRIANGLE like the one in the upper view of figure 6-24. The triangle is drawn to scale so that the length of the horizontal side equals the unit run (which is always 12), and the length of the vertical side equals the unit rise.