EXAMPLE IN ESTIMATING
1. Following the rules and suggestions already given in Estimating and Calculating Quantities, Part 1, the estimate for a house will be made as a practical example, the drawings on which it is based being shown in the accompanying plates. In making the estimate, the various portions of the work are taken in the order in which they naturally occur in the erection of the building, following, as closely as possible, the estimating schedule heretofore given.
As far as possible, the figures given in the example should be checked up by taking off quantities and performing all the indicated work. It is only by actually making the calculations that any practical benefit from the work will be derived. No two estimators, working separately, will arrive at exactly the same results; therefore, in following the calculations in this example, some discrepancies between the figures of the person performing the estimating and the ones given will no doubt be found. These discrepancies should not be important ones, however, and by carefully studying the methods followed, results substantially the same as those computed here should be obtained.
EXCAVATION
2. In calculating the cubic yards of earth excavated for the cellar, all measurements are taken from the foundation plan and the sections. The plan is blocked out as shown in the accompanying Cellar Plan, and the area of each block found; then, by multiplying the sum of these partial areas by the depth of the cellar, the cubic contents is determined. The trenches for the foundation walls of porches and for the footings of cellar walls are calculated separately, as also are the excavations for piers, drains, cesspools, area, etc.
Cellar Excavation
| Square Feet | Cubic Feet | ||
|---|---|---|---|
| Quantities | |||
| Block A, 23' 4" × 16' 4" | 381.0 | ||
| Block B, 14' 6" × 20' 10" | 302.0 | ||
| Deduct 4" × 3' 0" | 1.0 | ||
| Add for projection of wall, (13' 6" + 7') ÷ 2 × 3' = | 30.8 | 331.8 | |
| Block C, 27' 6" × 17' 5" | 479.0 | ||
| Deduct for breaks in wall, 1' 7" × 6' 8" and 2' 6" × 3' | 18.0 | 461.0 | |
| Block D, 26' 6" × 10' 5½" | 277.2 | ||
| Block E, 16' 8" × 11' 6½" | 192.4 | ||
| Deduct for breaks in wall, 6' 6" × 1' 11" and 3' × 5" | 13.7 | 178.7 | |
| [2] Block F, 9' 10" × 9' 7½" ÷ 2 | 47.3 | ||
| [3] Block G, 14' × 14' × .7854 ÷ 2 | 77.0 | ||
| Deduct for portion of semicircular part, | |||
| included in F, 12" × 14' approximately | 14.0 | 63.0 | |
| Total area of excavation | 1,740.0 | ||
| Contents, 1,740 sq. ft. × 6.5 ft. (depth) | 11,311.0 | ||
Excavation for Wall Footings [4]
| Square Feet | Cubic Feet | ||
|---|---|---|---|
| Quantities | |||
| a b, 26' × 2' 6" | 65.0 | ||
| b c, 5' 6" × 3' | 16.5 | ||
| c d, 9' 9" × 2' 6" | 24.4 | ||
| d e, 17' 6" × 2' 6" | 43.7 | ||
| e f, 27' 4" × 2' 6" | 68.3 | ||
| f g, 9' 2" × 3' 8" | 33.6 | ||
| g h, 21' × 2' 6" | 52.5 | ||
| i j, 27' 7" × 2' 6" | 69.0 | ||
| j a, 31' × 2' 6" | 77.5 | ||
| k l, 20' 2" × 2' 6" | 50.4 | ||
| Chimney, 12' 6" × 4' (approximately) | 50 | ||
| Deductions | 10.4 | 39.6 | |
| q r, 16' 4" × 1' 10" | 29.9 | ||
| r s, 9' 2" × 1' 10" | 16.8 | ||
| m n (less openings), 7' 9" × 2' 6" | 19.4 | ||
| o p, 20' × 1' 10" | 36.7 | ||
| Total area of excavation for footings | 643.3 | ||
| Contents, 643.3 sq. ft. × 10 in. (.833 ft.) depth | 535.9 | ||