| 50 M. ft. B. M. at $13 per M. | $ 650 |
| 170 M. ft. B. M. at $26 per M. | 4,420 |
| ——— | |
| 220 M. ft. B. M. at $23 | $5,070 |
This is equivalent to 126 ft. B. M. per cu. yd. of concrete. New forms were made for each floor except the sides of the girder molds which were re-used so far as they would fit, but the roof forms were made from lumber used for the floors. In all no more than 20 per cent of the form lumber was used a second time. In round figures new lumber was required for 80,000 sq. ft. of concrete; this gives a cost for lumber of 6.4 cts. per sq. ft. The construction of the column and floor forms is shown by Fig. 238. A force of 15 carpenters at $4.40 per day under a foreman at $35 per week erected and tore down forms; the carrying was done by laborers at $1.70 per day working under a foreman at $35 per week; carpenters worked an 8-hour and laborers a 10-hour day. Forms for one floor were framed and erected in 8 to 10 days. The cost of forms for 1,740 cu. yds. and 80,000 sq. ft. of concrete and per M. ft. B. M. was as follows:
| Item. | Per cu. yd. | Per sq. ft. | Per M. ft. |
| Lumber | $2.90 | $0.064 | $23.00 |
| Framing, erecting and removing. | 2.00} | 0.057 | 15.67 |
| Handling lumber | 1.10} | 8.70 | |
| —— | ——— | ——— | |
| Totals | $6.00 | $0.121 | $47.37 |
Fig. 238.—Column and Floor Forms for Four-Story Garage.
The lumber had a considerable salvage value which is not allowed for in the above figures.
Concrete.—The concrete was a Portland cement, ¾-in. trap rock mixture, mixed wet in two Chicago Improved Cube Mixers equipped with charging buckets. The mixers were located on the ground floor, one at the rear and one at the front of the building, both discharging directly to a hoist. With a gang of 30 men at $1.70 per 10-hour day under a foreman at $35 per week a floor was concreted in 2 days, the columns being concreted the first day and the floor being concreted the second day. The labor cost for mixing and placing concrete and for fabricating and setting reinforcement was as follows:
| Item. | Per cu. yd. |
| Mixing and placing concrete | $1.95 |
| Erecting and setting steel | 2.05 |
| —— | |
| Total | $4.00 |
The cost of concreting includes the cost of granolithic surface for the floor slabs. The girder reinforcement was made up into unit frames and the frames were set as a unit, horses set over the molds being used to suspend and lower them into place. The cost of $2.05 per cu. yd. is equivalent to ¾ ct. per lb. Summarizing, we have the following cost for materials and labor on forms and for labor mixing and placing concrete and reinforcement:
| Per cu. yd. | |
| Lumber for forms | $ 2.90 |
| Labor on forms | 3.10 |
| Labor on concrete | 1.95 |
| Labor on steel | 2.05 |
| —— | |
| Total | $10.00 |