Page:Cassells' Carpentry and Joinery.djvu/98

80 other. Fig. 347 is a conventional view showing girder, 12 in. by 10 in.; binders, 8 in. by 6 in.; bridging joists, 8 in. by 2¼ in.; and matchboard ceiling. There









being no ceiling joists, the girders and binders have their under-edges moulded. To intercept sound, the floor may be pugged as shown. The strength of wooden girders often being weakened to the extent of one-eighth by being mortised and housed to receive the binders, various forms of stirrup irons have been introduced to carry the ends of the binders, and thus they are well supported without the girder being weakened. Two different forms of malleable iron stirrups are illustrated by Figs. 348 and 349, and one of wrought iron by Fig. 350. A system of supporting ceiling joists by connecting them to the bridging joists by nailing them to strips of wood is shown at Fig. 351, but it has become obsolete.

In warehouses and factories where there are heavy loads and vibration the girders