=11.= Besides the actual cost of excavation, the contractor, in
estimating, must include such items as office expenses, builder’s
profits, etc. The following method of figuring, which is employed by
the estimator of a large contracting firm in the eastern part of the
United States, will therefore be found useful. As in the preceding
case, the prices will be found to vary in different localities;
therefore, the figures given should only be used as a guide in
estimating.
The prices are based on labor at $2 per day of 8 hours and a two-horse
team and driver at $5 per day of 8 hours. The excavation is assumed
to be made in ground varying from made ground to a moderately stiff
clay. The prices do not include the cost of shoring or pumping, and
are based on the assumption that there is no frost of any account
while operations are being carried out. Four classes of excavation are
recognized:
1. Excavation in trenches up to 5 feet deep, excavated material spread
on site about trenches, including back filling around walls, costs from
40 to 50 cents per cubic yard.
2. Trenches from 5 to 10 feet deep, excavated material spread on site
adjacent to trenches, including back filling around walls, costs from
65 to 75 cents per cubic yard.
3. For cellars, or similar digging, up to 6 feet deep and having an
area large enough to use a plow for loosening the earth (say areas
50 ft. × 20 ft. and over), excavated material being spread on site
adjacent to work, costs from 33 to 38 cents per cubic yard if a scoop
can be used, and from 40 to 45 cents per cubic yard if the material
must be loaded on a wagon to haul it out of the excavation.
4. When the conditions are the same as those just given, except that
the excavation is from 6 to 10 feet deep, the price is about 45 cents
per cubic yard.
The prices just given do not include hauling, except short hauls
immediately in the vicinity of the operations. The cost of hauling will
depend on the distance to the place where the material is to be dumped.
=12.= To obtain the cost of any of the classes of excavation just
given, including hauling, divide the hire of the team per day by the
number of cubic yards that can be removed to the dumping place per day,
and increase the preceding prices by that amount.
To figure the cost of sheet piling, measure the area to be sheet-piled
and allow for such stringers and braces as judgment may suggest. Since
the lumber may be used for other purposes after serving as piling,
its value should be estimated at 75 per cent. of the market price. It
usually costs about $7 per thousand feet to put the piling in place. As
a rule, 3" × 10" planks are used for this purpose.
The foregoing prices cover the general run of building work. For large
office buildings and other structures of a similar nature, where it is
necessary to excavate to a depth of about 25 feet and where several
varieties of ground are likely to be encountered, an average price for
digging (exclusive of pumping or shoring, but including a haul not
exceeding 1 mile) is $1.25 per cubic yard. If large boulders are likely
to be encountered in excavating, the price should be at least $1.50 per
cubic yard.