218 



071 Concrete as a Building Material for 



Ifedo 



A 



I 



observed, however, that the smaller the rough materials are 

 broken up the stronger will be the concrete. 



Building Walls with Concrete. 



1. Without a Patent Apparatus. — The simplest method of build- 

 ing with concrete is as follows. See Figs. 7, 8, 9, previous page. 

 Firmly fix stout wooden uprights, say 3x9 in., at each angle 

 of the building, and at the junction of cross or division walls. 

 They should be kept at one uniform width apart, either with 

 bolts, or cross-pieces of wood ; they should also be stiffened with 

 stays from the ground, so as to keep them perfectly steady and 

 upright. 



Two 3 X 11 in. planks, one for each face of the wall (or four 

 3 X 7 in. deals, i.e., two for each face, each pair firmly secured 

 with ledges), are required to form a trench the whole length and 

 width of the intended wall. 



A piece of iron, as shown in Fig. 10, A and B (suited to the 

 thickness of the wall), dropped over the planks at intermediate 



distances between the uprights 

 Fig. 10. — Iron Clamp. and wedged up, will prevent 



the planks from being bulged 

 out by the'pressure of the con- 

 crete ; a few such pieces, to 

 suit 6-inch or 9-inch walls, 

 could easily be made by any 

 village blacksmith, of light bar iron. 



When the trench is filled with concrete up to the ground line, 

 and above that to the top of the planks, they should be moved 

 higher up, and secured with counter wedges (see Figs. 9 and 11). 

 The lower edges of the planks should be allowed to cover the 

 concrete about an inch and a half (see Figs. 11 and 12), so as to 

 securely confine the next layer of concrete and prevent any 

 oozing out, see also Figs. 8 and 9. It will be observed that the 

 trench being shallow it may be filled in a day, thus allowing 

 the concrete to set during the night, so that the trench may be 

 ready for moving higher up the next morning for refilling. 

 The sides, too, being only a single plank, will be lighter and 

 more handy to move up and down than if made up of two or 

 three in depth ; the shallowness of the trench (only 9 or 10 

 inches deep) will enable an unskilled labourer to fill it in better 

 with the concrete, and so make better work. It will also be more 

 open to supervision, although the rate of progress will not be 

 quite so fast as if the trench had been 18 inches deep ; but where 

 unskilled workmen (such as farm labourers) are employed, the 

 slower rate of progress will be advantageous because more sure. 

 I should mention that no scaffold-poles will be required, as 



