Production → Duration → Cost

CSTM 370 -ESTIMATING I

Estimate Durations

• Durations should be estimated based on available resources which include labor, material and equipment.

• These durations should reflect the planned resource productivity and anticipated site conditions.

Resource Availability

The key to estimating durations is the availability of resources. It is imperative that the estimator to realistically address labor resources…

• Labor - the main focus…

• Crew Mix

• Who?

• How Many?

Time Unit Selection

Durations can be expressed in any convenient time unit, however, for estimating purposes the following are commonly used:

• Days

• Hours (used for determining cost)

Calculating Durations

Two elements go into calculating durations...

• Work Quantity

• Production Rate

Activity Duration =

therefore…

OR

= 10 days = 400 hrs

Work Quantity Production Rate

500 cy 50 cy / day

500 cy 1.25 cy / hour

Necessary Information

• Quantity of Work

• Production Rate

• Total Hours

• Based on a Crew

• Productivity

• Crew Mix

• Quantity Takeoff

• Outside Information

• Estimating Guides

• Industry and trade organizations

• Manufacturers, Fabricators and suppliers

• Historical Data

• Past Experience

• Constructive Imagination

Quantity & Productivity Data

?

Crew Mix & Cost

Turn man-hours into Costs…

One crews consisting of:

3 carpenters & 2 laborers per crew

3 Carpenters @ 20.50/hour = $61.50

2 Laborers @ 16.25/hour = $32.50

• $32.50 + $61.50= $94/5 = $18.80 Crew Average Wage Rate

• $18.80 x 300 hours = $5,640.00

Formwork: concrete walls

Formwork: concrete walls shoes/wedges/cleats

Formwork: concrete walls corner details

Formwork: concrete walls bulkheads

Formwork: concrete walls control joints

Work-up Sheet Basics…material A Material for wood forms QUANITITY unit price Material Total

List out parts to panels QUANITITY unit price Material Total

List out parts to panels QUANITITY unit price Material Total

List out parts to panels QUANITITY unit price Material Total

Total Mat. A

Material Total A / SF of panels

SF / uses = SF price of panels

B Material to Erect Forms QUANITITY unit price Material Total

List out parts to erect QUANITITY unit price Material Total

List out parts to erect QUANITITY unit price Material Total

List out parts to erect QUANITITY unit price Material Total

List out parts to erect QUANITITY unit price Material Total

List out parts to erect QUANITITY unit price Material Total

Total Mat. B

Material Total B / SF to erect panels

SF / uses = SF price of erect.of forms

C Material of no re-use Same as above Same as Above

D Material of no re-use Same as above Same as Above

E Material of no re-use Same as above Same as above

Totals of A,B,C,D, etc

Work-up Sheet Basics…labor

A Labor to Build Panels

Crew Composition QUANITITY unit price Total Cost A

and

Production

Labor Cost / SF of panels

(NOTE: sf of panels can = 1 panel or total for project)

Labor cost per SF / uses = A

B Labor to Erect Forms QUANITITY unit price Total Cost B

Labor Cost / SF of forms erected

C Labor to Remove Panels Same as Above

D Labor to Clean & Repair Panels Same as Above

Totals of A,B,C,D, etc

Factors Affecting Durations

You plan it and guess what happens? Poor productivity in relation to:

• Nature of the work

• Labor and Equipment Productivity

• Management skill

• Material and Equipment Availability

• Seasonal Conditions

• Work Restrictions

• Quality of Work

• Concurrent Activities

Variables to Evaluate

• Production Rate

• Quantity or work in place

• Total man-hours

• Crew Size or Mix

Work-up Sheet Basics…material Project : Work-up Sheet Example Estimator: JBP Page 1 of 1

Location: Ply Form - 4'x8' panel system Architect: DCH Architects

Based on 40 LF of form 8'-0" @ high Project Size: 320 SF

Date: 8 / 22 / 20xx Sheet Title: Material Only

Checked By: JBP Extensions Checked by: JBP

Notes Description Quantity unit Labor Extension unit Material Ext.

A Mat'l to Build Panels (4'x8')form plywd - 3/4", 9 ply 3 2 0 sf 1 63 5 2 2

2x4 plates 6 0 bf 0 53 3 2

2x4 studs 2 7 0 bf 0 53 1 4 3

misc. hdwe. 1 0 % 10% 7 0

7 6 7

$767 - ÷ 320 sf = $2 40 /sf$2 40 ÷ 4 uses = $0 60 /sf

Totals of A,B,C,D & E

0 60 + 0 57 + 0 39 + 0 06 + 0 09 = $1 71 /sf

Mat’l to Erect & Material of No Re-Use (no re-use items are separate items)

Work-up Sheet Basics…labor

Labor to Erect, Labor to Remove & Labor to Clean & Repair

Project : Work-up Sheet Example Estimator: JBP Page 1 of 1

Location: Ply Form - 4'x8' panel system Architect: DCH Architects

Based on 40 LF of form 8'-0" @ high Project Size: 320 SF

Date: 8 / 22 / 20xx Sheet Title: Labor Only

Checked By: JBP Extensions Checked by: JBP

Notes Description Quantity unit Labor Extension unit Material Ext.

A Labor to Build Panels (4'x8')1 carpenter @ $25.00 1 0 mhr 25- 2 5 0

2 laborers @ $15.00 1 0 mhr 30- 3 0 0

60 min/panel or 1 hour/panel 5 5 0

$550 - ÷ 320 sf = $1 72 /sf$1 72 ÷ 4 uses = $0 43 /sf

Totals of A,B,C,D, etc

0 43 + 8 98 + 3 28 + 0 70 = $13 39 /sf