. are emplo3ed, and the situa-tions in Avhich they are placed. The principal timbers of a roof arethe following, but they are not all used in every roof: the tie-beams, wall-plates, collar-beams, king-posts, queen-posts, struts,principal rafters, common rafters, ridge-piece, collar-beams, purlins,and pole-plates. The Tie-beam (a), fig. 3, is a horizontal piece of timber, which. Fig. 3. extends from wall to wall, and rests upon the Wall-plates (b) ateach end. It is employed for the purpose of connecting tlio feet ofthe principal rafte
. are emplo3ed, and the situa-tions in Avhich they are placed. The principal timbers of a roof arethe following, but they are not all used in every roof: the tie-beams, wall-plates, collar-beams, king-posts, queen-posts, struts,principal rafters, common rafters, ridge-piece, collar-beams, purlins,and pole-plates. The Tie-beam (a), fig. 3, is a horizontal piece of timber, which. Fig. 3. extends from wall to wall, and rests upon the Wall-plates (b) ateach end. It is employed for the purpose of connecting tlio feet ofthe principal rafters (C), which would otherwise have a tendency topush out the walls by their own weight, and the weight of thematerials placed upon them. In roofs of large span, it is necessarythat tlie tie-beam should be well supported in some point orpoints, between the ends on wliich it is supported, for if this be notdone it will sag and draw either one or both of the principal raf-ters towards its centre, and thus destroy the stability of theframing. The King-post (D) is sometimes used for this purpose. It 316 Woodwork, Carpentry, etc. is a piece of timber placed in a vertical position, connecting thepoint where the two principal rafters meet, and the centre of thetie-beam. When the king-post is not thought to be sufficient to support thepressure which may be on the framing. Queen-posts (B), fig. 4, maybe used, which are pieces of timber pla
Size: 1995px × 1252px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1850, booksubjectenginee, bookyear1856
