1907. 
TIIH RURAL NEW-YORKER 
6i9 
THE OUTWARD PRESSURE IN A SILO. 
I have been greatly interested in reading in many of 
the farm papers and also hearing the subject discussed 
concerning the cause of the hoops bursting on silos, and 
wish to give my views on the subject, gained from a 
large field of experience in building and observation. 
For a number of years, when I was new at the busi¬ 
ness and only knew from reading about them what a 
silo was like, I used to be afraid they would burst, but 
after building a few and hooping them with wire fencing 
and having no trouble from bursting hoops, I began, to 
see that the fault was not in the great outward pressure 
of the contents, but in the swelling of the dry lumber, 
caused by the hot, moist mass in the interior. I am 
positive that I have never built a silo 30 feet or more 
deep that was hooped strong enough to stand the strain 
of outward pressure of 330 pounds per square foot. As 
I have read several articles lately in the papers stating 
that it was “a well-established fact” that silage in a 
silo 30 feet deep would exert an outward pressure of 
330 or more pounds per square foot, I have wondered 
how it was that such a large per cent of them withstand 
the strain. In building a silo I have always warned 
the owner or user against leaving the hoops too tight at 
filling time, as they would be apt to burst from the lum¬ 
ber swelling, and so far I have never heard a complaint, 
and judge that none of them has had any trouble that 
way. I am positive as can be that there is almost no 
outward pressure to silage at any time, as the nature 
of this material is to pack downward instead of 
outward, and if one leaves it alone in a silo when filling 
it will stack up in the middle of the silo to quite a 
height and pack very solid. I saw three silos go through 
a fire four days from the time the filling was finished 
and the silos entirely burned away and left the contents 
standing naked. Not only that, but they stood for 
weeks and months, or till the last of the piles had been 
fed, and they did not burst out and fall down, but stood 
almost as firmly as they would with the silo around them. 
The largest one was 17x36 feet in size, and it stood from 
Oct. 20 till in January before they began feeding from 
it, and lasted till in March. Now, as these silos were 
just filled and settling, they were exerting their greatest 
outward pressure, and if it was as extreme as some try 
to make out they would have burst out and come down 
in a pile, and the feed would have been ruined. As it 
was the silage was good and was fed with a very small 
amount of waste. 
In a concrete or masonry silo the outward pressure 
would be of no consequence at all, as there would be 
nothing to swell, and likewise no pressure to amount to 
anything. The cause of cracking would be the same as 
in any other building; that is, from faulty work or ma¬ 
terial and a poor foundation. Wheat or grain tanks 
have been built of re-enforced concrete as high as 84 
feet and used successively and the re-enforcement was 
a flat band of iron put in every foot in height. The 
walls were only eight inches thick the whole way up. of 
course resting on a wide re-enforced foundation. Now, 
in a grain tank of that height the outward pressure 
would be something immense, as grain would, owing to 
its smoothness', press out about as hard as down, and I 
believe that if a re-enforced wall eight inches thick, 84 
feet deep will stand the* strain of being filled with grain 
one need have uo fear whatever of the outward strain 
in a silo wall and a wall six inches thick above the 
ground line, with a quarter-inch rod in it every foot in 
height, will stand all requirements in silos up to 16 feet 
in diameter and 40 feet deep. If more than 16 feet in 
diameter a wall eight inches thick could be used up for 
eight or 10 feet, and then a six-inch wall above that, and 
a little more iron used in the first 10 or 12 feet. The 
concrete needs to be of a first-class quality made of 
crushed rock and sand or good coarse, sharp sand con¬ 
taining pebbles up to one inch in diameter and about 
one part of cement to six parts sand or crushed rock. 
There are simple tests whereby material can be tested 
and the right proportions of cement found out, and as 
gravel varies so much in different pits it would be sen¬ 
sible to test the material on the ground and go according 
to the test rather than by hearsay. In standard tests 
a proportion of one of cement to seven crushed rock 
and sand is claimed to make solid stone. What is need¬ 
ed is to get all of the voids between the grains of ma¬ 
terial filled and then concrete is at its best. In any 
case of a wall where you want it to stand get down to 
good soil and be sure of drainage in clay soil, and then 
make a wide slab of concrete under your wall, the 
wider the better. This slab should be from six inches 
to a foot thick, and well re-enforced, and it will then 
bridge many of the difficulties,and defects that happen 
with walls. In case of silo foundations if the ground 
should be soft and springy or quicksand dig out the 
whole floor surface down to the foundation and a foot 
outside of the foundation wall and then put down a 
six-inch re-enforced floor over the whole surface, with 
plenty of three-eighths inch iron rods in it and you will 
have a foundation that will hold up in good shape. 
While I do not wish to discredit others who think they 
are right in, regard to the bugaboo of outward pressure 
in a silo, I do think the matter has been greatly over¬ 
done and that the theory of the bursting hoops and 
cracked walls has been wrongly applied. 
Michigan. _ r. c. angevine. 
TROUBLE WITH A STORAGE CELLAR. 
In 1902 I built a building 33x30 feet for storage pur¬ 
poses. The basement was dug partially in rock, and was all 
enclosed with a 20-inch wall laid double. The windows and 
doors were all double or two sets In each opening. The 
ceiling was nine feet high: joists eight inches wide were 
laid on top of the wall, then the basement was ceiled over¬ 
head with matched ceiling painted with three coals of lead 
and oil. On top of the ceiling sawdust was filled in to top 
of joists and then floor laid on top. There is one swing 
ventilator in center of ceiling that is open most of the time. 
The basement is used for storing vegetables in Winter and 
handling fruit in Summer; is always cool in Summer and 
HYBRID ROTUNDIFOLIUM GOOSEBERRIES. FIG. 308. 
See Rurallsms, l’age 622. 
never freezes in Winter, but the trouble is the moisture from 
the vegetables and the rock bottom cause the ceiling to decay 
so much that some of the joists are rotted and in places the 
ceiling is dropping off. I have now sound White oak joists 
to put in, but; what shall I do for the ceiling? I had thought 
of getting galvanized sheet iron, paint on both sides with 
^ore paint and nail on over the ceiling that is on, and 
through into the new joists, and also leave the old ones in. 
Is there a better way for durable ceiling? a. h. 
Ohio. 
It appears probable from the statements of A. H. 
that the decay of the ceiling and joists has resulted 
from insufficient ventilation of the cellar, although an¬ 
other cause may possibly have been instrumental in 
bringing about the decay. It sometimes happens that 
walls are so constructed that capillary action is strong 
enough to carry moisture up through the wall from the 
damp soil outside to the sills and allow it to spread 
laterally into the joists and ceiling, on the same prin¬ 
ciple that oil moves through a wick. If this latter con¬ 
dition has been the cause of the decay the fact will be 
evident from the rotting being most extensive around 
the walls. Cn the other hand, if the decay is the result 
of insufficient ventilation there would be a general de¬ 
cay, tending to be even greater away from the walls. 
I assume, of course, in making these statements, that 
conditions are such as to prevent the sawdust and ceil¬ 
ing from ever becoming wet through water from above, 
caused by leaks or other conditions. 
If the decay has resulted from insufficient ventilation 
the use of galvanized iron is all righr. but it would not 
be of material help to paint it, provided it is a good 
quality of galvanized iron, as it should be. It is very 
important, however, that the old joists, if left in, and 
the sawdust and ceiling should be thoroughly dried out 
before the upper floor is again laid. The rotting is the 
result of fungus growth, and could easily spread to the 
new wood if sufficient moisture were present, develop¬ 
ing a condition that is commonly known as dry rot. If 
there has been much decay in the sawdust it would be 
better to use new and to fill only to within an inch of 
the upper floor, and then, when the upper floor is laid, 
provide a few auger holes letween each pair of joists 
at opposite ends so as to permit a little interchange of 
air above the sawdust. These holes need not be more 
than two 54-inch openings, but should be covered with 
wire netting to prevent mice entering. 
If the decay has resulted from dampness coming 
through the wall, carried to it by the damp soil out¬ 
side, this may 1 i remedied by preventing the roof water 
from falling near the wall and grading so that surface 
water drains quickly away. If, to lessen the liability of 
freezing, the entire wall has been covered with earth up 
to the sills, except where the windows are, this of course 
facilitates' the entrance of capillary moisture which 
would favor the rotting of the sill and joist. In such 
a case it would be well to lay the joists on galvanized 
iron, to cut off the moisture, and if the earth placed 
close to the wall, down for a couple of feet and for a 
foot out from the wall, were coarse gravel and sand or 
cinders, only the very surface being covered with soil, 
this would materially lessen the entrance of capillary 
water. But, whatever the conditions which have resulted 
in the decay, it is important, from the standpoint of 
fruit and vegetables as well as from that of preventing 
decay of the ceiling, that ample ventilation be provided, 
and this means that provision must he made some way 
for air to enter the cellar by some other opening than 
that by which it escapes, otherwise the ventilation is not 
likely to be effective. It is quite important for such a 
storage that a ventilating shaft should be provided, 
which is to all intents and purposes a chimney, and it 
should rise out of the building just as a chimney would. 
For a storage space of the capacity here under consid¬ 
eration not less than an eight or 10-inch galvanized iron 
flue, or something else as effective, should be installed 
and provided with a close fitting damper which permits 
complete regulation. Provision for the entrance of air 
may be any opening where the inflow of the fresh air 
in the coldest weather would not strike immediately on 
products sensitive to frost. Two or three small open¬ 
ings distributed, for the entrance of fresh air, are bet¬ 
ter than a single opening. These should be provided 
with arrangements for closing, if necessary during se¬ 
verest weather. F * KING - 
ALFALFA AS A WEED. 
It is amusing to see so many easterners trying to 
grow Alfalfa, and make a failure of it year after 
year. Here we are having a time to keep the plants 
under subjection. It is one of the worst weeds we 
fruit growers have to contend with. It will get started 
in our orchards in spite of all we can do, and unless 
it is chopped out while young it will be almost im¬ 
possible to keep it down, and not only this, but it will 
increase a thousandfold in one year. I have a large 
peach orchard in which two tons of h'ay can be cut 
to the acre three times, making six tons to the acre, 
all because my place had been leased for three years. 
Whn I left this farm there wasn’t a spear of Alfalfa 
in it; now it cuts all this hay. Every seed came into 
the patch by irrigation water and volunteer. I have 
as yet noticed no bad effects from it, and it may prove 
to be a blessing in disguise to the orchard, unless it 
will injure the trees when it is plowed up, as we have 
to cut it deep in order to kill the immense roots. 
Sweet clover is another pest we have to contend with, 
but as it is a biennial plant, is not so hard to get rid 
of. This latter, under good conditions, grows eight 
feet high on our rich soils. g. w. hoover. 
Garfield Co., Coh_ 
The large stories of success with asparagus' have 
started plenty of get-rich-quick people into action. One 
man who never grew the crop purposes to start with 
1*0 acres—another who has a good garden patch talks 
of 50 acres! Easy, gentlemen! Walk first! It takes 
more brains and harder study to handle 10 acres of 
asparagus than it does to become a fair lawyer or 
doctor. Go easy! Grow into the business and master 
it as you go. 
