Small buildings can usually be raised high enough to allow working room, whereby the form may be filled right up to the top with concrete. The mixture should be a wet one. (Proportions, 1: 2: 4.)
Where buildings are too cumbersome to be raised by “jacking,” to a sufficient height to give head-room, it will be found necessary to make the foundations 3 inches wider than the sill. Carry the forms to the desired height and utilize this extra 3 inches of width for placing the concrete in the forms. The top board of the forms may also be left off until you are ready to place the last of the concrete. In this case the last batch of the concrete should be very wet. Tamp the concrete until it comes up flush with the bottom of the sill, to the entire width of the wall.
Be sure to leave a space in the concrete wall, under and on the sides of the underpinning support, so that the building may later be lowered back onto the new foundation and the timber removed. This opening must be slightly larger than the underpinning support. After the building has been lowered fill these openings with concrete. Lower the building after the foundation has been in two weeks.
A Concrete Entrance Floor
At a point 3 feet from the building, dig a trench 6 inches wide and 18 inches deep—the length of this trench to be 2 feet greater than the width of the doorway of the building. From the edge of the trench nearest to the building, dig away the earth between trench and building to a depth of 1 foot, and place here, to a depth of 6 inches, a fill of either coarse gravel or crushed rock. Do not, however, place any of this gravel fill in the trench. Mix concrete 1: 2½: 5, and lay same, first in the trench, and then on top of the gravel fill; sloping the surface so that it just meets the floor level at the doorway. Before the concrete has had time to set, provide a runway slot for the sliding doors—or better, build little guides or humps with the concrete, to hold the doors in position. If the doors happen to be swinging ones, place a gas pipe or iron socket in the soft concrete, for a “shove-fastener.”
Note the concrete curb on the right of entrance door. This prevents the gravel that surrounds the building from washing down onto the approach and getting in the way of the doors. To build this curb, use 1-inch planks placed on top of the concrete floor, to serve as forms to hold concrete in place.
| Materials Required |
|---|
| One cubic yard of crushed stone or screened gravel; |
| 2½ cubic yards of sand; |
| 5 bags of Portland cement. |
This entrance floor was constructed in half a day, by one man.