Estimating in Building Construction

(Barré) #1
Wood 171

shape (design) are possible. Ducts, piping, and conduit
may be easily incorporated into the trusses. The trusses are
only part of the system and must be used in conjunction
with a deck of some type. Typical truss shapes are shown in
Figure 13.57.


Specifications. Check the type of truss required. If any
particular manufacturer is specified, note how the members
are to be attached (to each other and to the building) and
what stress-grade-marked lumber is required. Note also any
requirements regarding the erection of the trusses and any
finish requirements.


Estimating. The estimator needs to determine the
number, type, and size required. If different sizes are


required, they are kept separate. Any special requirements
for special shapes are noted, with a written proposal from
the manufacturer or supplier. If the estimator is not famil-
iar with the project, arrangements should be made to see
the contract documents for the complete price. A check is
made to see how the truss is attached to the wall or column
supporting it.
If the trusses are to be installed by the general contrac-
tor, an allowance for the required equipment (booms,
cranes) and workers must be made. The type of equipment
and the number of workers will depend on the size and
shape of the truss and the height of erection. Trusses 400
feet long may be placed at the rate of 1,000 to 1,500 sf of
coverage per hour, using two mobile cranes mounted on
trucks and seven workers.

FIGURE 13.57.Typical Wood Truss Shapes.
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