MILL CONSTRUCTION BUILDINGS 



underfloor. Material is surfaced on all sides and edges of 

 plank beveled to serve as a finish on the ceiling below. 



Where plank floors are laid flat, the boards should be two 

 bays in length if possible and laid to break joints every 4 feet. 

 With laminated floors, it may be difficult to obtain plank two 

 bays in length. A strong and stiff floor will result if the planks 



Fig. 4. Laminated Floor with Joints at Quarter Points. 



are laid with the ends extending between centers of girders 

 with one plank laid across the girder at frequent intervals 

 (every sixth or eighth piece) to act as a tie in the floor. Or, 

 by another method, the ends of planks should join at or near 

 the quarter point of the span between girders, taking care to 

 break joints in such a way that no continuous line across the 

 floor will occur. Fig. 4 shows an instance of this kind in which 

 the span between girders is 16 feet and the planks are 16 feet 

 long. The method of lamination shown in Fig. 4 is as follows : 



Every fourth piece of plank extends from center of girder to center of 

 next girder. Next to this piece of plank, a second piece of the same length 

 is nailed with the end spaced at a quarter point of the span between girders, 

 thus allowing one end of the length to project three-fourths of the way 

 across one span and one-fourth way across the other. The next piece of 

 plank is placed over the opposite girder in the same manner that the previous 

 is placed over the first girder. The lamination is completed by placing a 

 length of plank from center of girder to center of girder as in the first 

 case. Care is taken to see that each plank is nailed firmly in place with a 

 tight joint between each piece of the floor. 



In laying laminated floors, it is advisable to omit the last 

 two planks at walls until after glazing and roofing have been 

 completed. Then these spaces should be filled in close against 

 the walls. It is often recommended that laminated floors be 

 laid without nailing to the girders which support the floor, so 



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