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XI. — On the Comparative Chca]mcss and Advantages of Iron and 

 Wood in the Construction of Roojs for Farm- Buildings. By 

 Philip D. Tuckett, Land Agent and Surveyor. 



The inquiry whether iron roofs are not as applicable to farm 

 buildings as to railway stations, warehouses, tScc,, is so natural in 

 itself, and was so often put before me by friends and clients, that 

 I was induced, for my own satisfaction and guidance, to go into 

 a series of detailed calculations as to cost, scantlings, &c., the 

 results of which are given below. I approached the subject with 

 no prepossessions on either side, and a perfectly unbiassed judg- 

 ment, or, if anything, with some natural feeling of sympathy for 

 the newer and less bulky material. 

 Iron may be applied — 



1. As a roof-covering in place of slate, tiles or other material, 



2. In the framing or main construction of a roof instead of 

 timber, and irrespective of the material of the roof-covering. 



I. As a roof-covering, plain or corrugated iron can be con- 

 structed at a very moderate cost, but the objections to its use are 

 numerous. 



Galvanised sheet-iron, of which these roofs are generally 

 formed, should theoretically be free from rust, but the coating 

 of zinc which the iron receives in this process is scarcely ever so 

 pure and uniform as to secure this result, and unless pretty 

 Irequently painted or otherwise coated (an inconvenient and 

 expensive liability) the iron is very liable to rust through in 

 a {g\y years, producing leaks, which involve constant trouble and 

 cost in repairing. Its expansion and contraction under alterations 

 of temperature is another objection, especially in the case of plane 

 iron, rendering it liable to "buckle up" if not very carefully 

 laid, and also tending to the bulging out of the side walls or 

 other supports on which it is placed ; the difficulty of inserting 

 skylights, when the roof is curved, is a smaller inconvenience. 

 But perhaps the two chief objections to the use of iron for farm.- 

 buildings are: First. That, being a good conductor of heat, it 

 exposes the live stock to needless extremes of heat and cold ; and 

 Secondly, That, treat it how you will, it seems difficult to avoid 

 positive ugliness, and this is hardly excusable in farm-buildings, 

 however plain, especially if they are connected with a country 

 house. 



For these reasons iron must clearly wholly be condemned as a 

 roof-covering for agricultural buildings. 



That a roof either of corrugated or plain sheet-iron can be put 

 up at a moderate price will be seen by reference to the specimen 

 roofs, Nos. 3, 4, 5, 6 and 7, described below ; but Nos. 1 and 2 



