No measured share of contract value for wet-day overhead left unclaimed

What it is. None - a worked calculation gives 0.35% to 0.81% of contract value for 20 unclaimed wet days, but no source measures how many wet days a real job leaves unclaimed.

Sample. The calculation, not a measurement: 10% preliminaries x 45.49% time-related / 261 week days a year x 20 days = 0.35% of contract value; 20% x 45.49% / 226 working days x 20 days = 0.81%. 45.49% is O'Leary and Vaz-Serra table 6; 10% to 20% is their introduction, citing Chan and Pasquire 2002; 261, 226 and 20 are Transport for NSW TS 01566 Table E2.1. The time-related share of preliminaries comes from 30 senior Australian estimators; the working days and the 20 wet days are the ones Transport for NSW builds into its own daywork labour rate for major civil contracts.

What it is not. Recorded as `none` on purpose. A share of contract value is the one unit a product multiplies by a contract value, and this one rests on an assumed day count, so it is not held as a figure. See weather_wet_day_overhead for the same arithmetic as a cost per day. The 20 wet days a year that Transport for NSW estimates are priced into the rates, so their overhead is paid for; this is the cost of the same number of days going unclaimed beyond the allowance. How many unclaimed wet days a real job loses is not measured anywhere we found. The 10% to 20% preliminaries figure is a UK 2002 number read second-hand, and the estimators' survey was mostly building work. Use your own preliminaries rate and wet-day count if you have them.

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
• Transport for NSW (2024), QA Specification TS 01566 (G2-C2): General Requirements (Major Contracts)
  Annexure G2-C2/E, Table E2.1, rows c, h and i · source record

History

• 2026-11-02 subtype 'weather' is now the registers' cause 'penalty_days' (schema 3.0.0, SM070)
• 2026-11-02 subtype moved from 'penalty_days' to 'unclaimed_delay_costs' on SM070 P2 review: the figure measures time-related site overhead that keeps running on the days (extended preliminaries and site overheads), which is what the delay-costs cause covers, not liquidated damages running on time never claimed (the penalty_days cause)
• 2026-11-02 exposure_value 0.0035 (range 0.0035 to 0.0081, derivation calculated, unit ratio_of_contract) set to none before any tagged release, SM070: as a ratio of contract the worked example displaced the 10.6% variations figure on New South Wales jobs because its Transport for NSW source made it the nearest evidence, about 30 times lower on an assumed count of 20 unclaimed days. The arithmetic is kept in sample_note.

forfeited_entitlements/weather_unclaimed_days_share_of_contract · AU, AU-NSW · F, F42 ·the record ·link to this figure ·dispute this figure(or email support@demiton.io)