70 



FARM BUILDINGS IN SOUTH AFRICA 



iron grids (Figs. 70 and 71) into the wall at intervals (see Fig. 68). The 

 air-bricks commonly used are 9" by 6" in size, i.e. they occupy the space 

 of two bricks. The aperture left in the wall to receive, at its outer end, 



Fig. 70. 



Fig. 71. 



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Fig. 72. 



the air-brick is bridged either by a Welsh arch (Fig. 72) or by a stone or 

 concrete lintel (Fig. 68). These apertures are situated immediately above 



the damp course. Air- 

 bricks should be in- 

 serted in all four outer 

 walls of a building, 

 and apertures should 

 . be left in party walls 

 so as to connect the 

 spaces underneath the 

 floors of the various 

 apartments and give through ventilation. An examination of the plans 

 for a small cottage, shown in Fig. 214, will make clear the arrangement 

 of air-bricks in outer walls, and of apertures in party walls. The latter 

 are indicated in the ground plan, by the dotted lines crossing the party 

 walls. 



Upper Floors. — Fig. 73 illustrates a corner of a specially strong 

 floor designed to bear heavy loads, induced by the storage upon it of 

 materials such as sacks of mealies, etc. Such a floor might, for instance, 

 be put in an apartment above a seed, machine, or other room. If 

 properly constructed the floor illustrated will bear with safety a load 

 of 540 lbs. per square foot of floor surface. 



The flooring boards are laid on a series of 9" by 1£" joists, spaced 

 15 inches apart from centre to centre. They should not be less than 



