34 



STEEL ROOF TRUSSES AND MILL BUILDINGS. 



CHAP. I. 



skilled workmen with steel trowels and shall be worked to a final surface. Under no condition 

 shall a dryer be used, nor shall water be added to make the material work easily. 



Specifications for Wood Floor on a Tar Concrete Base. Floor Sleepers. Sleepers for 

 carrying the timber floor shall be 3 in. X 3 in. placed 18 in. c. to c. After the subgrade has been 

 thoroughly tamped and rolled to an elevation of 4^ in. below the tops of the sleepers, the sleepers 

 shall be placed in position and supported on stakes driven in the subgrade. Before depositing 

 the tar concrete the sleepers must be brought to a true level. 



Tar Concrete Base. The tar concrete base shall be not less than 4.5 in. thick and shall be 

 laid as follows: First, a layer three (3) in. thick of coarse, screened gravel thoroughly mixed with 

 tar, and tamped to a hard level surface. Second, on this bed spread a top dressing i| in. thick 

 of sand heated and thoroughly mixed with coal tar pitch, in the proportions of one (i) part pitch 

 to three (3) parts tar. The gravel, sand and tar shall be heated to from 200 to 300 degrees F., 

 and shall be thoroughly mixed and carefully tamped into place. 



Plank Sub-Floor. The floor plank shall be of sound hemlock or pine not less than 2 in. 

 thick, planed on one side and one edge to an even thickness and width. The floor plank is to be 

 toe-nailed with 4 in. wire nails. 



Finished Flooring. The finished flooring is to be of maple of clear stock, in. finished thick- 

 ness, thoroughly air and kiln dried and not over 4 in. wide. The flooring is to be planed to an even 

 thickness, the edges jointed, and the underside channeled or ploughed. The finished floor is to 

 be laid at right angles to the sub-floor, and each board neatly fitted at the ends, breaking joints 

 at random. The floor is to be final nailed with 10 d. or 3 in. wire nails, nailed in diagonal rows 

 16 in. apart across the boards, with two (2) nails in each row in every board. The floor to be 

 finished off perfectly smooth on completion. 



The finished flooring is not to be taken into the building or laid until the tar concrete base 

 and sub-plank floor are thoroughly dried. 



, 

 ,--i Tar 





Flooring 



Z"FIoc 



ing 



^~Tie Rott 



(a) BRICK ARCH FLOOR 



Corrugated Jren '"-Tie Rod 

 (b) CORRU6ATED IRON FLOOR 



(c) RE1HFORCED CONCRETE FLOOR 



(</} REINFORCED CONCRETE FLOOR 



(F) 

 PEHCOYD CORRUGATED FLOORING (g) Z BAR FLOOR 



(h) ANGLE & PLATE 

 FLOOR 



d) "BUCKEYE "FIREPROOF FLOORING (/) MULTIPLEX STEEL PLATE FLOOR 



FIG. 26. EXAMPLES OF SHOP FLOORS ABOVE GROUND. 



Shop floors above ground may be made of timber resting on beams, of brick arch construc- 

 tion, (a) Fig. 26, of concrete with corrugated steel arch centers as shown in (6), of reinforced con- 



