This section is from the book "A Treatise On Architecture And Building Construction Vol3: Stair Building, Ornamental Ironwork, Roofing, Sheet-Metal Work, Electric-Light Wiring And Bellwork", by The Colliery Engineer Co.. Also available from Amazon: A Treatise On Architecture And Building Construction.
42. The varieties of gutters that will be treated of in this section are: eaves gutters, roof gutters, parapet gutters, and belt-course gutters of various materials and for various classes of buildings. A little has already been said about valleys, flanks, and other sheet-metal roof work in Carpentry, and need not be repeated in this section.
An eaves gutter of the simplest kind, is shown in Fig. 29; it is known as a half-round hanging, or trough, gutter, and is commonly used on ordinary frame buildings. The standard widths are 3, 4, and 5 inches measured across the top of the inside. The bead is about 1/2 inch in diameter and is turned outwards. These gutters are suspended from the eaves with adjustable malleable-iron hangers set at about 3 feet centers. When they are secured to shingle roofs, the hangers may be simply nailed or screwed on to the shingles as shown in Fig. 29. A better method, however, is shown in Fig. 30, where the hangers are firmly nailed to the roof-boarding before the shingles or slates are laid.
The pitch or grade of hanging gutters should not be less than 1 inch in 8 feet and the gutters should be hung low enough to allow the snow to slide over them. Three-inch gutters are useful only for porches, bay windows, and other small roofs. The 4-inch size should be used on the main roof when the horizontal or projected area does not exceed 500 square feet. The 5-inch size is used chiefly on factories, warehouses and at the rear of large city buildings, where the projected area does not exceed 1,500 square feet. Hanging gutters of this class should be used only when the eaves overhang the wall.
When a hanging gutter is attached close to the wall, the back of the gutter is extended up under the shingles or slates at least 6 inches, as shown in Fig. 30, the object being to prevent heavy winds from blowing the rain drops against the siding. The gutter is held up in front by tension straps a, a. The lower ends of the straps are soldered to the bead, and the upper ends are nailed to the roof. Braces b, b are soldered inside, and above the water line, to prevent the gutter from collapsing and sagging. Small clips c, c are soldered on the straps at an angle, to divert any current of water which may flow along the strap and thus escape over the edge of the gutter. This gutter should be graded about the same as that shown in Fig. 29.