Chap. XXIL

TIMBER ROOFS.

1343

Fig. 2161.

RtDING-lUH'SlB, LIDOtJRNE.

Sheds for Ship Building are of various kinds : those constructed at Rosiercs in France are very simple, resting upon posts placed upon a solid mass of masonry: a series of suchspans must be rendered secure at their commencement, and the two outer need someadditional security at the feet of the rafters to prevent their spreading. At the ship-yards of L’Oricnt, the roof,composed of iron and benttimbers, is supported by archesand columns of masonry ; lightbeing admitted to the ship-wrights bydormers constructedalongthe sides at the springingof the roof: occasional ties arehere requisite, which areabove the vessel when it is letoft’the blocks to be launched.

Fig. 2162.

SHEDS FOR SIUP-BCILU1.no.

Fig. 2163. LONGITUDINAL SECTION.

The walls of masonry and post above are well adapted for the struts and braces intro-duced to receive the middle gutters placed between the several roofs in succession ; andthe water is ingeniously led from them by pipes into a drain formed within the wall below,and conducted into the ocean without injuring the inclosure: when the timber is wellseasoned properly framed together, and all injurious effects from the rain prevented, roofsformed in that manner will endure for a length of time : it is always necessary to provideagainst the action of strong winds by bracing the sides in every possible position.