1 88 



FRAMEWORK 



placed on small platforms resting on the lower chords of the roof 

 trusses. 



Copper Copmg- 



FIG. 840. SAW TOOTH ROOF FOR ROCK DRILL BUILDING.* 



Erecting and Machine Shop of P. & L. E. R. R. The locomotive- 

 erecting and machine shop of the P. & L. E. R. R., at McKees Rocks 

 is 533' X 168' i", and is designed with a self-supporting frame with 

 brick curtain walls. 



The details of the roof are shown in the cross-section in Fig. 84d, 

 the machine shop being well lighted by three saw tooth windows. The 

 roofing is asphalt and felt laid on i^" tongued and grooved boards. 

 The gutters are heavily flashed with asphalt and felt. The roof water 

 in the saw tooth part is carried by 4" conductors to 5" vertical discharge 

 pipes, attached to alternate columns (40 ft. apart) as shown. The de- 

 tails of the saw tooth windows are given in Fig. I57a. The floors have 

 a 1-3-5 Portland cement concrete base 4" thick, on this are placed 

 five layers of felt saturated with asphalt for waterproofing. This is 

 covered with a layer of dry sand about 5" thick and the 4" X 3%" 

 floor stringers are well bedded in the sand. The wearing floor con- 

 sists of a sub-floor of 2^4" yellow pine and a top floor of \ l /" tongued 

 and grooved maple. Wire boxes are put in as shown in Fig. 84d to 

 carry power and light wires. 



* Engineering News, June 20, 1905. 



