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FARM BUILDINGS IN SOUTH AFRICA 



the layer of reeds and tied to the thatching lath below. These thin wires should 

 be attached at every foot distance along the thick outer wire. The wires are 

 covered by the grass thatching on top, which is put on as before described, the 

 tarred string lacing the bundles to the thatching laths being simply passed 

 through the layer of reeds where required. 



Making the Roof Watertight; Fixing the Flashings 



Where the roof-covering meets a vertical wall, special provision must be 

 made to prevent leakage. This is usually done by the provision of " flashings " ; 

 for instance, where a chimney shaft penetrates the roof covering, and at gables. 



The flashings for a chimney shaft are illustrated by Fig. 224, where H.F. is 

 called a horizontal flashing and S.F. a side flashing. 



Fig. 224. 



The upper edge of the flashing is bent over to the extent of about 1 inch, 

 which part is inserted and wedged into the joint between the bricks. The lower 

 edge is turned over for at least 6 inches ; this part rests on top of the thatch 

 and is laced with galvanised wire to the purlins below, just as was explained for 

 the roof capping, the holes being no larger than necessary and soldered up after 

 the wire is in position, and all is complete. 



The side flashing, S.F., consists of an " under-flashing," with one edge bent 

 up against the chimney shaft and overlapped by the upper-flashing or " apron " 

 (see also Fig. 229). The apron consists of short pieces with their upper edges 

 bent over, about 1 inch, and let into (or " raggled " into) the joints between 

 the bricks. Each short piece overlaps the next one further down the roof-slope, 

 and also the under-flashing, by from 2 to 4 inches. Edges such as XX (Fig. 224) 



