Time-related site overhead per working day, Australian estimators

What it is. AUD per working day at the high end (AU$870 at the low end), 20 wet days is AU$17,400 to AU$40,300.

Range A$870 to A$2,010 (scenario)

Sample. 30 senior Australian estimators put about 45.49% of preliminaries as time-related for the whole job; preliminaries are 10-20% of the contract sum. On a $5M job that is AU$870 to AU$2,010 per working day, depending on the overhead rate and the working days in the year.

What it is not. A WORKED EXAMPLE, NOT A MEASUREMENT. Both inputs are weaker than we would like: the 10-20% preliminaries figure is a UK 2002 number cited second-hand, and the estimators' survey was mostly building work. No open Australian civil source gives either number. Use your own rates if you have them. The unit is per wet day, so this figure is never multiplied by a contract value. Price year taken from the source's data year; not yet confirmed against the source's tables.

Our arithmetic. Worked on a $5M contract. High end: 5,000,000 x 20% preliminaries x 45.49% time-related = 454,900 a year, / 226 working days = 2,013, shown as 2,010. Low end: 5,000,000 x 10% x 45.49% = 227,450 a year, / 261 working days = 871, shown as 870. The 45.49% is table 6; the 10% to 20% is the introduction, citing Chan & Pasquire 2002.

Where it came from

• O'Leary & Vaz-Serra (2025), Challenges in pricing preliminaries costs for contractors: An Australian case study
  introduction citing Chan & Pasquire 2002; table 6 (30 Australian estimators) · source record

claim_window/weather_wet_day_overhead · AU · F ·the record ·link to this figure ·dispute this figure(or email support@demiton.io)