SHINGLES AND SHAKES 367 



Water shipment charges are based upon the number of shingles rather 

 than on weight, so that shingles shipped on vessels are often in the green 

 condition and partially air-seasoned before reaching their destination. 



The following standard shipping weights are recognized in the North- 

 west and delivered prices are customarily figured on this basis (see 

 grading rules for further description of grades) : 



Grades. 



Weight in Pounds per 

 M Shingles. 



Extra Star A Star, 16 in. . 



Standard A-i6 in. 



Extra clear-i6 in 



Choice A-i6 in 



Eureka-i8 in 



Skagit A-i8 in 



Perfections and Puget A-i8 in. 



160 

 160 

 i So 



1 80 



200 

 200 

 200 



The weights of southern white cedar shingles are as follows: 



Length. Inches. Width. Inches. Weight <fe P" M 



Xo artificial method of seasoning is generally applied to these shingles, 

 which accounts for their relatively high weights. They are commonly 

 shipped with little or no air seasoning as the wood contains a low per cent 

 of moisture. 



The competition of substitute materials for roofing purposes has 

 become a serious problem with shingle manufacturers. Those pro- 

 moting the use of substitutes for wood shingles have used the fire hazard 

 as their great argument. The modern movement in favor of better fire 

 protection in our cities has been used to favor the passage of ordinances 

 in many cities prohibiting the use of wooden shingles in congested centers 

 and restricting their use generally. 



The forms of substitutes for wooden shingles include a great variety 

 principal among which are asphalt, asbestos and combination shingles, 

 tar roofing, slate, tile, various metal forms and several patent materials. 

 The widespread demand for fireproof construction as applied to all kinds 



