418 Roofs for Farm-Buildings. 



from the double-floored buildings, for which a general width 

 of 24 feet, inside measurement, has been selected. 



In dealing with yards intended for internal subdivision, there 

 is room for much difference of treatment. Where the appro- 

 priation of the space can be definitely pre-arranged, the character 

 of the roof can be determined accordingly, and the evil avoided 

 of placing storey posts or columns in places where they may 

 afterwards be found in the Avay. 



Roofs constructed of wide spans to avoid the inconvenience of 

 internal columns, are open to the serious objection that while 

 they are more expensive, the shelter is less complete, and that 

 where erected in exposed situations they are more subject to 

 injury from wind, as well as to changes of temperature, than 

 roofs of small spans. 



Before bringing into notice the different roofs offered for illus- 

 tration, a few words on some leading principles are necessary to 

 simplify comparison. 



The desiderata governing the materials and construction of 

 the roofs of all farm-buildings are, strength and durability, an 

 equable temperature, and a comfortable and cheerful appearance 

 in conjunction with economy of cost. All embellishment should 

 be avoided ; the best appearance of farm-buildings being that in 

 which symmetry of proportion is combined with propriety of 

 the design with reference to the object of the buildings. 



The attainment of these advantages will depend on the nature 

 of the covering, which will rule the form and strength of the 

 framework, and consequently the cost of the whole structure. 

 This general observation includes the " pitch " of the roof, 

 which essentially depends on the covering material employed. 

 Much has been written and said upon this point, and most 

 elaborate tables have been prepared, to prove that the angle of 

 roofs should vary with climate. Without, however, entering 

 upon, or endorsing such a refinement as this, we may accept 

 the following "pitches" as correct for various descriptions of 

 covering. 



1st. For straw roofs a pitch equal to one-half of the span ; 

 2nd. For tile roofs of all kinds, a pitch equal to one-third ; 3rd. 

 For slate roofs a pitch equal to one-fourth ; and 4th. For iron 

 coverings of all kinds, a pitch equal to about one-fifth of the 

 span. 



The following is a statement of the weight per square of 100 



width will vary according to the materials used ; but the best width, measured 

 from the internal walls, is 24 feet. This is found to admit of alteration with the 

 least disturbance of the external shell, and it is well to anticipate a possible re- 

 division of the buildings consequent upon improvements in macliinery." 



