U8 



IM)USTi:lAL rsES OF WOOD. 



1. SliiiKjlfH for liOoJiiKj or to rorcr Walls. 



Shingles are either used for roofs, or to cover niasonrv or 

 cement walls, Avhich do not otherwise sufficiently exclude 

 atmospheric moisture. The most durable shingles are made 

 of oak- or larch-wood, but owing to the abundance of spruce 

 and Scotch pine, wood of these species is chiefl}' used, and 

 less frequently silver-lir wood ; beech- and aspen-wood are also 



sometimes employed. 

 Fi«- 46. The butts to be split 



must contain sound, 

 light, and straight- 

 grained wood without 

 knots, and therefore 

 the lower part of stems 

 is chiefly employed. 

 "Wood of inferior grain, 

 and less fissile may, 

 however, be split by 

 means of machines. 

 Shingles are pre- 

 pared of very diflercnt sizes, according to the manner in which 

 they are to be used. Roofs are usually covered with shingles 

 three deep, i. c, only a third part of each shingle being exposed 

 (fig. 4G), and such roofs are very durable and watertight. 

 Shingles used in this way are 16 — 24 inches long, 3 — 10 inches 

 broad, and from 2 inches down to half an inch thick. In many 

 countries they are so thin at one end as to be semi-transparent, 

 especially in the case of larch-shingles. Another kind of roofing 

 (Legdacher) is frequently employed in Alpine districts, the 

 shingles being 30 — 40 inches long, and 8 — 12 inches broad. 

 They overlap one another, and are fastened-down by nailing split 

 laths over them. In the case of tiled roofs, thin laths, 12 — 14 

 inches long and 2 — 3 inches broad, are placed wherever one tile 

 is superposed over another. 



Shingles are split radially from the butts, and the sectors 

 thus obtained are continually split until pieces of the right 

 dimensions have been secured ; they are then made smooth. 

 As the central portion of the butts cannot be used for shingles, 



