26 



STEEL ROOF TRUSSES AND MILL BUILDINGS. 



CHAP. I. 



Gutters. Eave or valley gutters should always be galvanized. Valley gutters should be 

 No. 20 gage. Eave gutters and conductors should be No. 22 gage. Gutters should be sloped not 

 less than I in. in 15 ft. 



WEIGHTS OF -EAVE GUTTERS AND CONDUCTORS OF GALV. IRON OR STEEL. 



Details of conductors and downspouts are given in Fig. 21. 



Adjusbgble 

 hanger every 

 4 Feet- 



Adjustable hanger 

 every 3 Feet for 



Eave and ]/a/fey Gutbers 

 usual/y N-??0 orsame gsge 



5Jope one inch in Fifteen 



Feel;. 



Order in Feet lengths- 

 Conductors usua/fy N-?? 



or ^a me gage as siding* 



FIG. 21. DETAILS OF CONDUCTORS AND DOWNSPOUTS. AMERICAN BRIDGE COMPANY. 



Purlins. Details of connections for purlins used for a corrugated steel roof are given in Fig. 

 22. 



Cornice. For details of cornice see the author's " The Design of Steel Mill Buildings." 

 ROOF COVERINGS. Mill buildings are covered with corrugated steel supported directly 

 on the purlins; by slate, tile or cement tile supported by sub-purlins; or by corrugated steel, 

 slate, tile, cement tile, shingles, gravel or other composition roof, or some one of the various pat- 

 ented roofings supported on sheathing. The sheathing is commonly made of a single thickness 



