CHIMNEYS AND FIRE-PLACES 49 



Joint for Farm Buildings. — Fig. 45 shows how the mortar joints 

 between bricks are commonly finished off in farm buildings. This type 

 of finish is called a struck or weather joint. 



The Attachment of Timber to Brickwork. — For this 

 purpose, one method employed is to build wooden blocks, 

 of a thickness equal to that of a brick plus two mortar 

 joints, into the brickwork wherever required to receive 

 the nails. These blocks, however, are large, and the 

 shrinkage in them is correspondingly great, hence they frequently become 

 loose. 



It is better practice to build thin slips of wood, about £ inch thick, 

 into the joints between the bricks where required, as the wall is being 

 built. These slips should be placed so that the nails are driven into 

 them across the grain, i.e. not into "end-wood." They are often cut 

 from ceiling boards. To these slips, woodwork, such as skirting- boards, 

 linings, architraves, etc., are nailed. 



When timber is to be fixed to a wall already built, wooden plugs 

 about 5 inches long are usually driven into the mortar joints between 

 the bricks or stones, to receive the nails. This, however, on account of 

 the wedging action involved, is apt to shake or displace the bricks or 

 stones, and the structure may be seriously weakened. A better plan, 

 though one involving more labour, is to drive the wooden plugs into 

 holes made in the brick or stone itself. 



It need hardly be mentioned that wooden plugs should never be 

 placed in walls near flues or fire-places. 



Chimneys and Fire-places. — Since, as a rule, fire-places require more 

 depth than can be provided in the thickness of the wall, a projection 

 to contain fire-place and flue is necessary. This projection is called a 

 breast ; it may contain more than one flue. 



In most cases the breast is built on the inner side of the wall, but 

 sometimes on the outside. With the latter arrangement more space is 

 available in the room, and the apartment also has a better shape. In 

 the piggery illustrated in Fig. 155 the breast is shown on the outer 

 side of the wall. 



Fire-places (see Figs. 46, 47 and 214). — A fire-place 3' G" wide is 

 large enough for a range, while for an open grate, such as is used in 

 sitting rooms, 2' 6" is a sufficient width. 



The fire-place should be so formed that the air is caused to pass 



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