Roofs for Fa rm-Bu ildings. 



129 



and suspending-rods ; timber is used for the rafters and struts, 

 and cast iron for the shoes and junctions, but in each case the 

 quantity of materials is reduced to a mininmm. 



Fig 22, is a roof of 35 feet span ; it is useful as providing 

 head-room, and has a light appearance. A roof constructed in 

 this form may be seen at Uphampton Home Farm, belonging 

 to Lord Bateman. The cost of this roofing will be 6/. 8^. per 

 square, or GZ. 19^. ()d. per square of ground (10 X 10) covered. 

 Fig. 23, is a roof for a like span ; it has been constructed by the 

 General Land Drainage and Improvement Company at Burleigh, 

 Hertfordshire. The cost is 5Z. 125. 6fZ. per square of roofing, 

 or 6Z. 17^. 6fZ. per square of ground (10 x 10) covered. Fig. 24 

 is an example of a light and cheap double tie-rod roof, on 

 thi; plan recommended by Colonel Emy, the French engineer. 

 Sheet 6 illustrates the covering of yards and large spaces. The 

 prices of the several examples will be as follow : — 



Iron Roofs. — The words " Iron Roofs " are generally under- 

 stood to mean those roofs in which both covering and frame- 

 work are wholly of iron, although when speaking of timber 

 roofs, the designation applies to the framework only, since no 

 one concludes that the covering is made of wood. 



In treating this branch of the subject it may be better, without 

 discussing terms, to repeat that iron covering, for reasons already 

 given, is deemed inapplicable to agricultural buildings, except 

 in the case of corrugated iron, in which the circular form it 

 generally assumes, renders support by framework unnecessary. 



The reason why iron frameicork for the support of the covering 

 is not resorted to will be manifest on an examination of the 

 following examples with the relative cost. 



They are six in number, as shown on Sheet 7. Fig. 28 is 

 constructed altogether of rolled flat iron. The principals are 

 placed 6 feet apart, and the boards which carry the slates are 

 laid from principal to principal. 



The remaining examples of roofs of this span are constructed 

 of rolled "y-iron rafters, purlins, and struts. 



VOL. II. — S. S. K 



