Estimating in Building Construction

(Barré) #1
Finishes 203

example, a 10-foot drywall will be used, but the installers will have to
be careful to lift the drywall roughly 3/4 inches off the floor. If there is
a concern about the hangers being able to do this, then a 12-foot dry-
wall should be purchased and cut. However, the latter adds material
and labor costs, and increases the amount of construction waste that
must be hauled away from the job.
If 10-foot sheets are to be ordered and installed vertically, it
would require 183 sheets.


Taping joints is also required. Enough tape must be provided
to cover the vertical joints between the gypsum board sheets. From
the information above, 1,000 sf of surface area will require 380 lf of
tape and 5 gallons of ready-mix joint compound.




EXAMPLE 16-3 RESIDENTIAL BUILDING


Exterior walls: gypsum board, 1/2 4  8 
Ceiling height: 8 feet
148 lf (from Section 13–4, Example 13-10)

Interior walls: 1/2-inch gypsum board each side
Ceiling height: 8 feet
149 lf (from Section 13–4, Example 13-18)

Ceiling area: 24 0  50  0 (5/8-inch gypsum wall board)

1/2–
Metal Trim: corners bead: 3 pieces at 8¿ 

118 sheets — -thick 4¿ 8 ¿ gypsum wallboard

40 sheets 5> 8 – -thick 4¿ 8 – gypsum wallboard

Using a 5 percent waste factor, the following would be ordered:

Drywall (sheets)1,200 sf>32 sf per sheet38 sheets

Ceiling area (sf ) 24  50 1,200 sf

Drywall (sheets)2,384 sf of wall>32 sf per sheet75 sheets

sf of wall149 lf of wall 8 ¿ ceiling height2 sides2,384 sf

Drywall (sheets)1,184 sf>32 sf per sheet37 sheets

sf of wall148 lf 8 ¿ ceiling height1,184 sf

Drywall screws7,000 drywall screws

1,000 screws per thousand sf

Drywall screws7 (thousands of sf )


Gallons of joint compound35 gallons of joint compound

5 gallons per thousand sf

Gallons of joint compound7 (thousands of sf )


Order 59 rolls

Add 10 percent for waste and assume 50-foot rolls

Linear feet of tape2,660 lf of tape

Linear feet of tape7 (thousands of sf )380 lf per thousand

Use 7,000 sf

sf of surface346 lf 10 ¿ ceiling height2 sides6,920 sf

Add 5 percent for waste — Use 183 sheets

Double the quantity for both sides

Drywall (sheets)346 lf> 4 ¿ per sheet87 sheets per side

Labor. Subcontractors who specialize in drywall installa-
tion generally do this type of work and may price it on a unit
basis (per square foot) or as a lump sum. The productivity
rates for hanging drywall are shown in Figure 16.6. The hourly
wage rates need to come from the local market conditions.

EXAMPLE 16-4 RESIDENTIAL BUILDING
Gypsum wallboard, nailed to studs:



16–9 Wetwall Construction


Wetwall construction consists of supporting construction,
lath, and plaster. The exact types and methods of assembly
used for this construction will depend on the requirements
of the particular job regarding appearance, sound control,
fire ratings, strength requirements, and cost.

Total cost$408.00928.00$1,336.00

$408.00 (ceiling)

Labor cost ($)40.8 hours$10.00 per hour

Hang and tape40.8 labor hours

3.4 labor hours per 100 sf

Hang and tape (labor hours)12.00 (hundreds of sf )

Total 3.4 labor hours per 100 sf

Taper (ceiling), 1.6 labor hours per 100 sf

Hanger (ceiling), 1.8 labor hours per 100 sf

Labor cost ($)$928.00 (walls)

Labor cost ($)92.8 hours$10.00 per hour

Hang and tape92.8 labor hours

2.6 labor hours per 100 sf

Hang and tape (labor hours)35.68 (hundreds of sf )

Total 2.6 labor hours per 100 sf

Taper (walls), 1.4 labor hours per 100 sf

Hanger (walls), 1.2 labor hours per 100 sf

Wall area1,184 sf2,384 sf3,568 sf

FIGURE 16.6.Labor Hours Required for Drywall Installation.

Labor Hours
Drywall per 100 s.f.
Gypsum Board
Nailed to Studs:
Walls 1.0 to 2.2
Ceilings 1.5 to 2.8
Jointing 1.1 to 1.8
Glued:
Walls 0.8 to 2.4
Ceilings 1.5 to 3.0
Jointing 0.5 to 1.2
Ceilings over 8 Add 10% to 15%
Screwed to Metal Studs Add 10%
Rigid Insulation, Glued to Walls 1.2 to 3.0
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