10 Aug., 1 9 II.] Silo Construction. 571 



Re-ixforcing. — While in the course of construction, the walls must be 

 re-infcrced by laying on the top of e\-ery ring ordinary fencing wire clipped 

 together at the joint and built in with the bricks; for the first 4 ft., three 

 wires to every course, and for the remainder, two wires — one wire only 

 mav be used if thought worth while for the top 6 ft. 



*The following are the quantities and directions for building a 69- ton 

 silo : — 



Walls. — In constructing a silo with cement or concrete bricks^^^ the 

 first operation is to make the bricks after the following manner. Good 

 clean sharp drift sand having been procured, and a good brand of cement, 

 clean up a site on the ground and measure out according to previous 

 mstructions. The whole should then be passed through a ^-in. mesh sieve, 

 and watered until sufficiently damp. This can be tested by taking up a 

 handful of the material and giving it a squeeze ; if it holds firmly together, 

 it is ready to be shovelled into the mould of the machine. 



The height of a 70-ton silo is 21 ft., and requires 1,710 bricks, 90 of 

 which form the footing course; the 100-ton silo requires 720 more bricks. 



Foundation. — Roughly level site for a diameter of 16 ft., making 

 provision if on sloping land for drains to carry off any flow of water. 

 Fix a centre point by placing a 2-in. pipe firmly in the ground, so as to 

 receive a 2-in. pole; from this centre attach a piece of quartering 7 ft. 3 in. 

 long to act as a trammel, which will describe a circle having a diameter 

 of 14 ft. 8 in. This will be the inside diameter of the silo when built. 

 Care should be taken to fix the pole plumb, so as to obtain the accurate 

 circle. 



Cut out a trench 6 in. deep and 12 in. wide, the bottom to be level. 

 The inside line of trench will be 7 ft. from centre pole. Then lay therein 

 two rows of cement bricks side by side with cement mortar, gauged 4 parts 

 sand and i part cement, and grout in solidly. The next course should be 

 laid lengthwise, using the 7 ft. 3 in. trammel to keep the same true to 

 centre. Each course of bricks must be well bedded and jointed in cement 

 mortar as above; and, in every course, lay along the centre of bricks 

 lengths of galvanized fencing wire as specified above, clipped together at 

 joint, first gouging out the brick to bed the wire in (this may be done when 

 making the brick by just running the finger over it). 



Form port holes as shown, two bricks wide by four courses high, the 

 inside face of brickwork to be bagged over smoothly so as to be free oi 

 mortar projection, and the V-joint of outside face struck smoothly with 

 point of trowel. Build in four 7 -in. x |-in. bolts in top of silo wall to bolt 

 down roof wall-plates. When walls are completed, the earth floor of silo 

 is to be levelled off about 3 in. above outside ground with earth filling 

 rammed to an even surface. 



If the silo should be erected on a very exposed situation and it is 

 found that heavy rain penetrates the wall, a weatherproof coating made 

 as follows may be used: — 2 lbs. soft soap, 12 lbs. alum, and 30 gall, 

 water, applied evenly to the outside of the silo bricks with a white-wash 

 brush. 



Roof. — The roof to have 4i-in. x 3-in. oregon wall plates bolted down 

 to brickwork, the ridge plate 9 in. x li in. propped up off wall plate with 

 4-in. X 2-in. stud halved on to same, and stayed with 3-in. x li-in. strut. 



Raftf.r.s. — The rafters to be 4-in. x 2-in. hardwood spaced 3 ft., 

 centres notched on to wall plates and well spiked to same and ridge. Fix 

 six 3-in. X \l-\n. collar ties to each pair of rafters to I»a(tcn rafters with 



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