Figure 4-13.-Gutters and downspouts: A. Half-round gutter;
B. K style gutter C. Round downspout; D. Rectangular
foundation. On flat roofs, water is often drained from
one or more locations and carried through an inside wall
to an underground drain. All downspouts connected to
an underground drain should be fitted with basket
strainers (fig. 4-1 2) at the junctions of the gutter.
Perhaps the most commonly used gutter is the type
hung from the edge of the roof or fastened to the edge
of the cornice fascia. Metal gutters may be the
half-round (fig. 4-13, view A) or K style (view B) and
may be made of galvanized metal, copper, or aluminum.
Some have a factory-applied enamel finish.
Downspouts are round or rectangular (fig. 4-13,
views C and D). The round type is used for the
half-round gutters. They are usually corrugated to
provide extra stiffness and strength. Corrugated patterns
are less likely to burst when plugged with ice.
On long runs of gutters, such as required around a
hip-roof structure, at least four downspouts are
desirable. Gutters should be installed with a pitch of 1
inch per 16 feet toward the downspouts. Formed or
half-round gutters are suspended with flat metal hangers
(fig. 4-14, views A and B). Spike and ferrule hangers are
also used with formed gutters (view C). Gutter hangers
should be spaced 3 feet OC.
Gutter splices, corner joints, and downspout
connections should be watertight. Downspouts should
be fastened to the wall by leaderstraps (fig. 4-12) or
hooks. One strap should be installed at the top, one at
the bottom, and one at each intermediate joint. An elbow
is used at the bottom to guide the water to a splash block
Figure 4-14.-Gutter hangers: A. Flat metal hanger with
half-round gutter; B. Flat metal hanger with K style
metal gutter; C. Spike and ferrule with formed gutter.