Estimating in Building Construction

3. List each of the concrete items required on the project.


4. Determine the quantities required from the working
   drawings. Footing sizes are checked on the wall sections
   and foundation plans. Watch for different size footings
   under different walls.

Concrete slab information will most commonly be

found on wall sections, floor plans, and structural details.

Exterior walks and driveways will most likely be identified

on the plot (site) plan and in sections and details.

Concrete 93

FIGURE 10.1.Foundation Layout.

FIGURE 10.2.Footing and Foundation Wall Detail.

EXAMPLE 10-1 CONTINUOUS FOOTINGS

The objective of this example is to determine the quantity of con-
crete in the 3 2 -wide continuous footings. From drawings S2.1
and S8.1 of the small commercial building found in Appendix A
and excerpted in Figure 10.1, it can be discerned that there are two
different sizes of continuous footings. The continuous footings on
the perimeter of the building are 3 2 wide, and the ones found on
the interior of the building are 3 0 wide. The following steps
should be taken:

1. Determine the linear feet of footing for each width.


2. Determine the cross-sectional area for each of the differing
   sizes.


3. Determine the volume and convert into cubic foot.

Determining the linear feet of continuous footing typically requires

some minor calculations. The dimensions listed on the drawings

typically reference the exterior face of the building or the centerline

of the structural framing. Neither of these dimensions is appropri-

ate for finding the linear feet of footing. In addition, the overlap that

would occur in the corners by taking the measurement along the

exterior face of the footing needs to be compensated. Therefore, the

best approach is to determine the dimensions along the exterior

edge and dimension so that there is no overlap. Figure 10.1 shows

the exterior dimensions and footing dimensions. The overlap in

the footings for walls A and B and walls B and C is because the

footing in wall B is below the footings in walls A and C. Figure 10.2

is a sketch derived from drawing S8.1 detail 13 (Appendix A).