24 



STEEL ROOF TRUSSES AND MILL BUILDINGS. 

 TABLE OF CLINCH NAILS. 



CHAP. I. 



In cases where flashing, cornice work, and several thicknesses of metal are to be fastened at 

 one point, rivets or bolts, other than standard lengths given will be needed. Closing rivets \ in. 

 long and bolts i| in. long will usually answer in these cases. 



If side laps of corrugated steel are to be riveted, rivets should be ordered, one for each lineal 

 foot of side lap, plus 20 per cent for waste. 



If corrugated steel is to be fastened to wooden purlins or timber sheathing, order 8d barbed 

 nails for roofing and for siding. These nails should be spaced one foot apart, for both end and side 

 laps; add 20 per cent for waste. Ninety-six 8d barbed nails weigh I Ib. 



Corrugated steel for roofing should be laid with two corrugations side lap if standard or 13 

 'corrugations side lap if special, and 6 in. end lap. Corrugated steel for siding should have one 

 corrugation side lap and 4 in. end lap, 



Louvres. Weights of Shiffier louvres of black iron or steel are as follows: 



Gage No. 

 20 

 22 



Weight per Square Feet. 

 2.7 Ib. 

 2.O Ib. 



The weight is obtained from Fig. 20, as follows: 



T ^l 45 



"cj *s r~^^j 

 * |g 



3 ^ H 



.s i O .x\ "O 







* LJ 



FIG. 2Q. LOUVRES. 



Louvres are estimated in square feet = 2h X length. 



To get weight multiply area by (1.7 X weight per sq. ft. of flat of material used). 

 Ridge Roll. Ridge roll is ordinarily of same gage as roofing and black or galvanized to cor- 

 respond with same. Ridge roll is usually made from an 18 in. flat sheet. 



WEIGHT OF RIDGE ROLL. 



