COST IN CENTS PER SQUARE FOOT OF REINFORCED- CONCRETE FLOOR SLABS SUPPORTED ON STEEL BEAMS =========+=========+========+=========+========+======== Thickness|⁵/₁₆-Inch| ⅜-Inch |⁷/₁₆-Inch | ½-Inch |⅝-Inch of Slab |Diameter |Diameter|Diameter |Diameter|Diameter Inches | Rods at |Rods at | Rods at |Rods at |Rods at | 6-Inch | 6-Inch | 6-Inch | 6-Inch | 6-Inch | Centers |Centers | Centers |Centers |Centers ---------+---------+--------+---------+--------+-------- 3½ | 14.87 | 15.58 | | | 4 | 15.75 | 16.46 | 17.24 | | 4½ | 16.62 | 17.33 | 18.11 | 18.87 | 5 | 17.50 | 18.21 | 19.00 | 19.75 | 20.87 5½ | 18.37 | 19.08 | 19.87 | 20.62 | 22.62 6 | 19.25 | 19.96 | 20.75 | 21.50 | 23.50 =========+=========+========+=========+========+======== CEMENT CELLAR FLOORS =20.= In determining the cost of =cement cellar floors=, the concrete proper and the top coat should be considered separately. The concrete proper is usually reckoned by the cubic yard. About 1 hour more is required to lay a cubic yard of floor than is necessary for plain concrete work. Therefore, in estimating, 25 cents per cubic yard, or the wages of a laborer for 1 hour, must be added to the figures given in Table II. A 1-3-6 mixture is generally used. For stone concrete, then, the cost of the concrete proper for a cement cellar floor would be $5.17 per cubic yard, exclusive of the cost of supervision and the builder’s profit. An analysis of the cost per square yard of top coat 1 inch thick for a cement cellar floor is as follows: Cost Cents ¼ hour, plasterer’s time, at 45 cents per hour 11¼ ¼ hour, laborer’s time, at 25 cents per hour 6¼ ¹/₁₅ barrel of cement, at $2 per barrel 13⅓ ⅛ barrel of white sand, at 75 cents per barrel 9⅜ ------ Approximate cost per square yard 40 To the foregoing should be added the cost of supervision and builder’s profit. CONCRETE BUILDING BLOCKS