=16. Plain concrete work= is usually paid for by the cubic yard. The
contractor furnishes all material, including the lumber, to make the
forms; he also erects the forms and removes them after the concrete has
been placed. There is no fixed practice regarding openings in walls.
Usually, small openings under, say, 100 square feet in superficial area
are considered as solid. All larger openings are deducted from the work
when measuring for payment. In some localities, the actual volume of
the concrete work is taken by the contractor as a basis of the cost.
In either case, it is of prime importance that the architect and the
contractor make some distinct agreement _beforehand_ as to exactly how
the concrete work is to be measured and paid for.
=Reinforced-concrete work= is also often measured by the cubic yard,
although sometimes it is contracted for as a finished building.
The steel reinforcement is sometimes included in the price. Often,
patented steel reinforcement is bought separately and delivered to the
contractor; at other times, the contractor buys the patented steel
or else makes it and pays a royalty to the holder of the patent.
Reinforced-concrete floors are sometimes measured by the cubic yard and
sometimes by the square yard, according to agreement. Pavements are
usually measured by the square foot or by the square yard.
In Table II are given the costs of stone concrete and gravel concrete.
These figures do not include builder’s profit, cost of superintendence,
or cost of forms. They are based on the following costs: Labor, 25
cents per hour; cement, $2 per barrel; sand, $1.50 per cubic yard;
crushed stone, $1.65 per cubic yard; gravel, $1 per cubic yard.
To the values given in the table, the price of the wooden forms,
both for material and erection, must be added. This of course varies
considerably, according to whether the work is straight or has a number
of corners and openings in it.