Estimating in Building Construction

Wood 163

board sheathing must be covered by another material (such
as brick, wood, or aluminum siding), while the plywood
may be covered or left exposed. All of these sheathing
materials are taken off first by determining the square feet
required and then by determining the number of sheets
required. The most accurate takeoff is made by sketching a
layout of the material required (as with the sheathing in
floor framing). The estimator must check the height of
sheathing carefully, as a building with a sloped soffit
(Figure 13.40) may require a 9-foot length, while 8 feet may
be sufficient when a boxed-in soffit is used (Figure 13.41).
Remember that the sheathing must cover the floor framing
(joist and joist headers) as well as the exposed parts of the
wall. When the wall is a shear wall, the sheathing must go to
the top of the wall.
Openings in the exterior wall are neglected unless they
are large, and the sheathing that would be cut out can be
used elsewhere. Otherwise, it is considered waste.

EXAMPLE 13-17 EXTERIOR SHEATHING

Gable0.5 24 ¿ 3 ¿2 gables72 sf

Wall148 lf of exterior wall 8 ¿ average height1,184 sf

Sheets1,256 sf>32 sf per sheet39.25 sheetsUse 40 sheets

Area (sf )1,184 sf72 sf1,256 sf

FIGURE 13.40.Sloped Soffit.

FIGURE 13.41.Boxed Soffit.

FIGURE 13.43.Special Wall Construction.

FIGURE 13.42.Gable End. 

Interior Walls

Interior walls are framed with studs, top and bottom plates,

and a finish on both sides of the wall. When estimating the

material for interior walls, the first step is to determine from

the specifications and drawings what thickness(es) of walls is

(are) required. Most commonly, 2 4 studs are used, but

2 3 studs and metal studs (Section 15-2) can be used. Also,

the stud spacing may be different from the exterior walls.

Next, the linear feet of interior walls must be deter-

mined. This length is taken from the plan by:

1. Using dimensions from the floor plan.


2. Scaling the lengths with a scale.


3. Using a distance measurer over the interior walls.


4. Using a takeoff software package, such as On-Screen
   Ta k e o f f s.
   On large projects, extreme care must be taken when
   using a scale, distance measurer, or software package since
   the drawing may not be drawn to the exact scale shown.
   Any walls of different thicknesses (such as a 6-inch-thick
   wall, sometimes used where plumbing must be installed) and
   of special construction (such as a double or staggered wall)
   (Figure 13.43) may require larger stud or plate sizes.
   Plates. Refer to the discussion under “Exterior Walls” ear-
   lier in this section.
   Studs. Refer to the discussion under “Exterior Walls” ear-
   lier in this section. As in exterior walls, deduct only where
   there are large openings and take into account all corners,
   wall openings, and wall intersections.
   Headers. Refer to the discussion under “Exterior Walls”
   earlier in this section.