UNIVERSAL PORTLAND CEMENT CO. 
55 
must be thoroughly mixed and enough water added to give a quaky con- 
sistency. The concrete may usually be placed in the excavation without 
any forms whatever, but in some kinds of soil light boards, held in posi- 
tion by stakes, may be necessary. The top of the foundation must be 
levelled off with a straight edged board and spirit level. After 24 hours, 
the foundations will generally have hardened sufficiently so that the walls 
may be built upon them. Where soft ground or quicksand is encount- 
ered, the foundation may be made 3 or 4 feet in width, to provide plenty 
of footing. 
If a monolithic silo is to be built, the vertical reinforcing for the walls, 
consisting of 3^-inch round rods spaced 3 feet apart, should be imbedded 
in the foundation a distance of 8 or 9 inches. If a block silo is to be 
built no vertical reinforcing need be placed. 
Table of Materials for Silo Footing and Floors 
Inside 
Diam. 
ol" Silo 
in Ft. 
1:S:5 
Con- 
crete 
Cu.Yds. 
Footings 
4 in. Base 
1:2:3 
Concrete 
Cu. Yds. 
Floors 
Footings and Floor 
Quantities 
Quantities 
Quantities 
Cement 
Bbls. 
Sand 
Yds. 
Gravel 
Yds. 
Cement 
Bbls. 
Sand 
Yds. 
Gravel 
Yds. 
Cement 
Bbls. 
Sand 
Yds. 
Gravel 
Yds. 
10 
2.44 
2.83 
1.27 
2.10 
.70 
1.22 
.36 
.54 
4.05 
1.63 
2.64 
12 
2.91 
3.38 
1.51 
2.50 
1.07 
1.86 
.56 
.82 
5.24 
2.07 
3.32 
14 
3.37 
3.91 
1.75 
2.90 
1.51 
2.63 
.79 
1.17 
6.55 
2.54 
4.07 
16 
3.84 
4.45 
2.00 
3.30 
2.04 
3.55 
1.06 
1.57 
8.00 
3.06 
4.87 
18 
4.31 
5.00 
2.24 
3.70 
2.64 
4.59 
1.37 
2.03 
9.59 
3.61 
5.73 
20 
4.77 
5.53 
2.48 
4.10 
3.32 
5.78 
1.73 
2.56 
11.31 
4.21 
6.06 
22 
5.24 
6.08 
2.72 
4.51 
4.04 
After the foundation is completed, the earth within should be dug out 
for a depth of about 8 inches, and a concrete floor built as shown below. 
The floor should be given a slight pitch in all directions to- 
ward the center, and, if necessary, an outlet to a line of drain 
tile should be put in. Outlets are not usually provided in silo floors, but 
in one or two instances silos have failed because of the pressure of a large 
The Floor 
I'Z^'/i- Concrete:-^ 
^1 
Floor |; 2 3 (^^omcrelte: 
Pitch of- f-uoor ^ To I 
T7=^ 
^^^^ 
Concrete Silo Foundation or Footing and Concrete Floor, suitable for either monolithic or block silo, 
showing drain with bell trap; an important detail not to be needlessly overlooked. 
