Horizontal silos provide the cheapest way to store and use silage. At one time such silos were merely earth trenches cut into hillsides, but today farmers, ranchers, and feedlot operators have a choice of well-designed long-lasting concrete structures to meet expanding needs. Using the tilt-up method to construct horizontal silos with ready mixed concrete is an economical on-farm procedure. Tilt-up construction can be built either above grade or below the ground. Above-ground horizontal silos are used in flat, poorly drained areas and require less site preparation, although buttresses are needed to support the wall panels. They are frequently left open at both ends.
A preferred location would be high and well drained, with surface water diverted away from the silo. The silo should be located away from any residence. Provisions must be made to protect it from blowing snow. All site grading and excavating must be done before starting concrete work. It is important to provide access for ready mix trucks and for equipment that will be used to lift panels. A site where panels would be partially supported by soil and partially by buttresses should not be selected.
For ease of construction, builders should prepare the site as recommended by the Midwest Plan Service. Remove all sod, debris, and soft spongy material to firm subgrade. Slope subgrade for drainage and fill with compacted soil as necessary to bring to proper elevation. The subgrade should slope 1 inch in 8 feet. Form the floor with lumber held firmly in place with stakes. The floor should be 5 to 6 inches thick. At the open end where heavy wheels cross the edge of the slab, thicken it to 8 inches by gradually sloping the subgrade at the rate of 1 inch per foot. The floor should be cast in strips of a width that can be quickly placed, struck off, and finished. By using alternate strips the farm builder can have several strips available for placing on the same day.