ROOF TRUSSES FOR DIFFERENT SPANS 



57 



,^r>> 



roof trusses suitable for spans varying from 9 to 38 feet, 

 spans, together with the scantlings, or dimensions of the various 

 are clearly marked on the 

 figures. 



The roofs shown by Figs. 

 51 and 52 are called collar 

 roofs. 



Fig. 53 illustrates a cross- 

 braced roof which is useful 

 when head-room is required along the mid- width of a building. 



These 

 timbers, 



SfW 3 ro /2 rcrr. 



Fig. 51. 



Sp/7// /2 ro /G reer. 

 Fig. 52. 



6'*/i"#">c£ P^-'i 



Sf>/t/v /3 roSOreer. 



Fig. 54. 



Fi». 54 shows a roof with tie-beam, collar and braces, while Figs. 



