On wall centering, be very careful to use boards of 

 the same thickness. Unequal boards give a very dis- 

 agreeable unworkmanlike surface. 



A hand-hole should be left in wall centering at var- 

 ious points to allow an examination of the concrete 

 before pulling the centering. 



In some cases the forms may be braced in against 

 spreaders to keep them lined up, but in place of braces 

 it is much more usual to employ wire ties or bolts 

 passing through the wall to hold the wall forms to- 

 gether. This means that the bolts have to be driven 

 out again or cut off and any wiring has to be cut in 

 order to remove the centerings. Instead of wire, band 

 steel may be used. It is passed throtfgh the cracks in 

 the boards and nailed around a cleat or stud. Use 

 T X-in. x No. 18 gauge, soft steel for ordinary work. 

 This is about equivalent to 2 strands of No. 9 annealed 

 wire. 



Wall ties, either bolts, wire or steel, should be put 

 through at right angles, or square with the wall. The 

 centering will be "skewed" if this is not watched. 



Turning up bolts with a monkey wrench is slow 

 work. Use a ratchet wrench or hand nuts. 



Wires will cut through wood with the weight of the 

 wet concrete on wall forms. Therefore to protect a 

 stud put a piece of scrap lumber under the wire. In 

 twisting up (using No. 9 annealed) do not twist too 

 tightly, or you will burn and kill the wire. 



Bracing for wall forms is poor practice if the walls 

 can be reached from both sides to use wire; straps or 

 bolts. If bracing is used, put no trust in nails, but use 

 positive shoulder action at all points, with nailing 

 blocks or otherwise. Never brace a shore back into 

 the ground without a base block under it. 



STAIRS. 



The centering for reinforced concrete stairs is a 

 simple matter. The soffit or under side of the rake 



