To securely brace the sections of this wall, large posts (called buttresses) are needed. These posts are the full height of the wall and are 12 by 18 inches square. The narrow side is set with the line of fence, and the buttresses are placed 11 feet apart from center to center. The forms for these buttresses are the same as for gate posts, with the exception that a beveled 2 by 4-inch timber is nailed vertically to the inside of each side wall of the form, 3 inches from the back board. This leaves a slot in the finished buttress, into which the slab sections of the wall are later “keyed.” Through these 2 by 4’s, at points 3 and 15 inches below the tops, bore ⅝-inch holes through which ½-inch reinforcement rods will be placed and allowed to project into the wall proper about 18 inches.
Locate the points for the centers of the buttresses, the first buttress at the beginning of the wall. Dig a hole for each buttress 12 by 18 inches and 4 feet deep and erect the buttress forms. Fill the forms with wet concrete, mixed 1: 2: 4. Do not forget to insert at the proper time the 3-foot lengths of ½-inch rods in the ¾-inch holes above mentioned. Brace the forms securely, to keep them in position. After the first two buttresses are in place, dig out the 1 by 4-foot foundation trench and, over it and between the buttresses, erect the box forms for the slab sections, with the sloping side next to the lot. These forms are made of 1-inch siding nailed to 2 by 4-inch studding securely braced at bottom and tied together by cross-pieces at the top. On the working side, add the siding as needed, so as to facilitate the placing of the concrete.
Remove the side forms for buttress just before placing the forms for wall proper. In the center of wall, within 6 inches of the top, embed a 10-foot length of ½-inch iron rod. After the wall is one week old, take down the wall forms, erect them between the next two buttresses, and proceed with the construction in the same manner.
Wind walls are often made with straight sides. While this takes more concrete, the saving in erection of forms probably offsets this additional cost.
The materials required for each 10-foot section of wall and 1 buttress are two cubic yards crushed stone or screened gravel, 1 cubic yard sand, 12 bags of Portland cement. Approximate cost, $15.00.
Concrete and the Silo
A silo is a tank for the preservation of fodder in its green state, for feeding stock at times when there is no natural pasture—that is in winter and in the hot, dry months of summer. By the use of silos fodder is canned very much as a housewife cans fruit or vegetables.
Concrete fulfils every requirement for a first-class silo, providing the added advantages of being absolutely fireproof and everlasting, possessed by silos built of no other material. For instruction in building silos, see Bulletin No. 21 of the Association of American Portland Cement Manufacturers, sent free on application.