Some interesting cost data are given by Mr. Reygondeau de Gratresse, Assoc. M. Am. Soc. C. E. (Engineering-Contracting, October 30, 1907), on the cost of forms used in erecting a reinforced-concrete garage in Philadelphia during the summer of 1907. The building was 53 feet wide, 200 feet long, and four stories high; also there was a mezzanine floor. Tongued-and-grooved lumber 7/8 inch thick was used for the slab forms, and 1 3/4-inch plank for the beams and girders.

The area of the 1,740 cubic yards of concrete covered by forms was:

Sq. Ft.

Footings

4,000

Columns

20,000

Floors and Girders

70,000

Total

94,000

For this work, 170,000 feet, board measure, or new lumber was bought; and 50,000 feet board measure of old lumber was used, the cost being:

50,000 ft. B. M. at $13

$ 650

170,000 ft. B. M. at $26

4,420

220,000 ft. B. M. at $23

$5,070

Since 220,000 feet, board measure, were used tor the 1,740 cubic yards, there were 126 feet, board measure, per cubic yard of concrete.

New forms were made for each floor, except the sides of the girders, which were used over for each floor, where the sizes would admit of this being done. The props under the girders were allowed to remain in place throughout the building until the entire job was completed. The forms for the roof were made entirely of the material used on the floors below. The area of concrete covered by the new lumber was approximately 80,000 square feet. This gives a cost for lumber of 6.4 cents per square foot.

A force of fifteen carpenters working under one foreman, framed, erected, and tore down all forms. Laborers handled all the lumber for the carpenters, except when they were at work mixing and placing concrete. The foreman was paid $35 per week, while the carpenters were paid an average of $4.40 for an 8-hour day. Laborers were paid 17 cents per hour, and worked a 10-hour day. Over the laborers was a foreman who received the same wages as the boss carpenter. The forms for a floor were erected in from 8 to 10 days. For the framing, erecting, and tearing down of the forms, the labor cost was about $3,480, which gives a cost of $2 per cubic yard. For the carrying and handling of the lumber, the cost was about $1,914, which gives a cost of $1.10 per cubic yard. This gives a total cost per cubic yard of forms as follows:

Per Cu. Yd.

Lumber, 126 ft. B. M.

$2.90

Framing, erecting, and tearing down

2.00

Handling lumber

1.10

Total

$6.00

This cost is high, owing to the fact that so little of the lumber was used a second time, there being only from 16 to 20 per cent so used. For the 220,000 feet, board measure, of lumber used on the job, the average cost per thousand for the forms was:

Per M.

Lumber

$23.00

Framing, erecting, and tearing down

15.67

Handling lumber

8.70

Total

$47.37

The cost per square foot of concrete for the area covered by forms was:

Lumber

$0.064

Labor

0.057

Total

$0.121

The cost per cubic yard for lumber and labor was:

Lumber

$2.90

Labor on forms

3.10

$6.00

It should be remembered that the lumber used in the forms had a salvage value, for which no allowance is made in the above $2.90.