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.
Molded, i. e., ornamental, eaves gutters are often attached to buildings in a manner very similar to that shown in Fig. 30, but while the gutter in this figure is laid with a pitch, such molded gutters are laid perfectly horizontal. In this respect they are defective, because all gutters should pitch down to the outlet pipes. In good practice, it is advisable not to run a gutter with a horizontal bottom, not only because the gutter is liable to overflow during heavy rain storms, but because a pool of water will remain in the bed of the gutter after the rain has ceased. To prevent an overflow, it is necessary to make molded eaves gutters quite large; and to properly drain them, it is necessary in some cases to install a false bottom which will grade down to the point of outlet with a suitable pitch.
When the gutters are made of iron, they should always be graded in order to prevent deposits of mud, which hasten corrosion.
44. Fig. 31 shows a copper molded eaves gutter set on the top of a brick wall of a fireproof building, which is provided with a terra-cotta roof. The bed of the gutter rests on a board a which is inclined, to give the proper pitch. The face of the gutter forms a continuous horizontal molding and is made from cold-rolled sheet copper. The front edge of the gutter lining is bent down over the face and is lock seamed to the copper molding as shown.
The back of the gutter is extended up over the terra-cotta slabs d and under the slates e. A series of brass straps c are spaced off along the gutter and secured at distances of not more than 3 feet, being bolted to the plank b in front with brass lagscrews. The rear end of each strap is run up under the slates and bolted through the terra-cotta slabs with brass bolts of proper length, large brass washers or plates being used under the slabs to prevent the nuts from sinking into them. Each strap is twisted one-half of a turn, as shown, to prevent roof water from working over the face of the gutter. The sheet copper is doubled and pinched at i to form a drip. In cold climates it is advisable to slope the back of the gutter, the space behind being thoroughly filled in solid. This will prevent the gutter from bursting with the formation of ice, if the conductor pipe should choke and the gutter fill with water.