142 FAEM BUILDINGS IN SOUTH AFRICA 



decay, but withstand the effects of water, frost, and fire, and hence are 

 practically everlasting. 



Concrete fence posts may be made in any of the usual types, and, 

 as their strength does not diminish, but rather increases with age, it is 

 not usually necessary for them to be of the same dimensions as new 

 wooden posts, for the latter are, as a rule, much stronger than is really 

 necessary in order to allow for decay below ground. 



Moulding Concrete Fence Posts. — About 1£ inches of concrete, composed 

 of 1 part cement, 2 parts sand, 3 parts coarse material broken to pass a 

 f-inch sieve and retained on a ^-inch sieve, should be spread evenly over 

 the bottom of the mould and carefully tamped so as to produce a 

 thickness of about 1 inch. On top of this layer two reinforcing rods 

 are placed about f inch from the sides of the mould, and pressed in 

 until about f inch off the bottom. Concrete is then filled and tamped 

 in thin layers to the level of the other reinforcements. These rein- 

 forcements having been deposited, the remaining f inch of concrete 

 is tamped and levelled off. 



There is a tendency for the rods to get out of place, and it is therefore 

 preferable to make some small links to hold them together in their 

 proper position. These, in turn, can be strung from the top of the 

 mould, which may be removed after most of the concrete has been put 

 in position. 



The concrete should be most carefully tamped into the moulds by 

 poking it with a small bar or paddle-shaped piece of timber, so as to 

 make it quite dense and to force into every corner and interstice of the 

 mould and between the steel rods. If care be given to this part of the 

 work the posts will have a good surface, free from any cavities — often 

 referred to as honey-combing — and the posts will be much more 

 efficient. 



Fig. 120 also shows the construction of a post and rail fence (Type 

 "E"), the finished form being shown in Fig. 121, while the mould 

 for making such posts is shown in Fig. 122. In this type of fencing, 

 rails or bars are inserted in holes left in the posts. The rails are kept 

 in place by concrete wedges fixed by cement mortar. The posts shown 

 in the illustration measure 6" by 4" by 7' long, while the rails measure 

 4" by 2" by 6' long. The reinforcement in both cases consists of £-inch 

 diameter round rods of steel. Such posts may also be employed to hold 

 the shift rails, which are in many places used in place of gates. Where 



