Roofs for Farm-Buildings. 123 



Per foot 

 Cube. 



Baltic fir : — s. d. 



When framed 3 4 



Unframed for Plates 2 10 



Cost price in builder's yard 2 7 



Wood, however, it should be understood, only deserves the 

 preference, to the exclusion of iron, for spans limited to 30 feet. 

 It is true that wrought-iron rods, with cast-iron rafters, shoes, and 

 junctions, are introduced into the trusses of the smallest spans ; 

 but this is simply a fashion opposed to economy. They insure 

 an apj^earance of lightness by the reduced size of the tie and 

 suspending-rods, when compared with the wood they displace ; 

 though they are so heavy when all the metal is weighed as to 

 directly defeat the object professedly aimed at. If this is found 

 to be the case when the materials are compared in the scales, the 

 preference for wood is still more decided with respect to cost of 

 labour, as will be seen by a comparison of the cheapest examples 

 of each character of roofing. The examples given of timber 

 roofs for 20 feet span (outside measurement) are shown on 

 Sheet 1, and are four in number. The cheapest is Fig. 1, 

 adapted for slate, and is that most generally adopted by those 

 architects who are more influenced by a regard for economy than 

 appearance. The cost of this roof will be found to be 8/. per 

 bay of 10 feet, including one truss, or 4/. ?>s. 6d. per square 

 (10 feet X 10 feet) of roof, or 4/. lis. 8d. for each square of 

 ground (10 feet X 10 feet) covered. 



The examples of roofs of 20 feet span, outside measurement, 

 will be found to cost as below : — 



Cost of Roofing complete per square of 100 feet (10 X 10). 



The examples of timber roofs of 24 feet span, inside measure- 

 ment, are shown on the same sheet, and are four in number. 

 The cheapest of these is Fig. 5, which is often used in spans 

 from 20 to 30 feet, adapted for slate, and is of the ordinary king- 

 post construction ; the cost is 4/. as. 4c?. per square, or 4/. 15s. lOd. 

 per square of ground (10 x 10) covered. Fig. 6 is somewhat 



