EXAMPLES OF ROOFS 261 



cost of this roofing is about $21 .00 per square complete in place on the 

 roof." The Brown Hoisting Machinery Co. has also used Ferroinclave 

 quite extensively for floors and side walls of buildings. 



Examples of Roofs. The Boston Manufacturer's Mutual Fire 

 Insurance Co., recommend the following roof for mill buildings : "Roofs 

 of ordinary type may be only of plank covered with composition or 

 other suitable roofing material. In special cases the roof should consist 

 of a 3-inch plank, I inch of mortar, a i-inch top board and a 5-ply com- 

 position roof. Such a roof is impervious to heat and cold." 



The roof of the machine shop of the Chicago City Railway is com- 

 posed of 2 x 6-in. tongued and grooved sheathing overlaid with 5 layers 

 of "Cincinnati" wool felt, having 100 pounds of cement to loo square 

 feet, and is covered with tar and gravel. 



The roof of the Lehigh Valley R. R. Shops at Sayre, Pa., is a slag 

 roofing on armored concrete. 



The roof of the Great Northern R. R. shops at St. Paul, Minn., 

 has double sheathing with I x 3-in. strips between the layers to provide 

 an air pace and prevent sweating. Monarch roofing is laid on the 

 sheathing. 



The roof of the Philadelphia & Reading shops, at Reading, Pa., 

 is felt on plank sheathing covered with tar and slag. 



The roof of the A. T. & S. F. R. R. machine shops at Topeka, 

 Kas., is Ludowici tile laid on 2 x 2-in. timber strips. 



The roof of the Union Train Shed at Peoria, 111., is Ludowici tile 

 laid on angle sub-purlins as shown in Fig. 87. 



Roof Coverings for Railway Buildings. The following abstract 

 of the report of the committee on roof coverings presented at the an- 

 nual meeting of the Association of Railway Superintendents of Bridges 

 and Buildings, 1902, will give a very good idea of the present practice 

 in covering railroad buildings. 



"Slate is much used for station buildings where there is not much 

 climbing for repair of skylights or telegraph wires. It has a life of 

 from 35 to 40 years, and the roof should have a pitch of not less than 

 6 inches per foot. Vitrified tile is very durable where rightly made 

 and laid on steep roofs, but is not adapted for ordinary railroad build- 

 ings. Shingle roofs last as long as 28 years, and should be laid with 



